emo/ndhc
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Initial commit.

Browse Source
This commit is contained in:
Nicholas J. Kain 2010-11-12 04:02:18 -05:00
commit 7a09ba2cf7
50 changed files with 5249 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
ChangeLog Normal file
View File

@ -0,0 +1,64 @@
20040906
accept_conns() trivial correctness fix: EINTR return from accept should
force continue rather than break in handling loop.
fail_on_fdne() is now file_exists() with a slightly different API.
20040818
Use inet_aton rather than custom function; daemon.[ch] removed.
20040817
ifchd no longer logs a "FATAL - select returned an error!" when it
is -KILL'ed.
20040626
pending_exit is now static volatile sig_atomic_t rather than
static volatile int for pedantic correctness issues.
20040614
Added --interface (-i) option that allows one to restrict the
interfaces that ifchd clients are allowed to modify. I
reccomend that this flag be used to further mitigate the possible
effects of a compromised client. By default, all interfaces
may be modified by clients.
Minor cleanups.
Clear corresponding namesvrs and domains on socket disconnection.
20040613
Factor out Linux-specific code into linux.c.
Nameservers and search domains now tracked per-connection to
prevent races where a client could force a writeout of data
provided by another client.
Interface name now cleared on connection close.
Make all headers idempotent.
Minor improvements to error messages.
20040612
Removed iffd[] array; this change makes the state machine action
functions (perform_*) depend on less external state.
HOSTNAME command now supported; it is not enabled by default.
If you wish for remote daemons to be able to change the hostname
of the local machine, use the --hostname (-o) option.
20040610
Added MTU support.
20040609
Robustify so that suicide() isn't called at every possible failure.
Harmless failures will now simply print an error to the log. Risky
or severe errors still suicide().
20040608
Added support for resolv.conf, namely "nameserver" and "search" entries.
Make strlist more robust and paranoid.
20040607
Improved accept() code to be much more robust; it can now properly error
recover. I hope this will fix the elusive random-exit problem that
plagues machines running the 2.6 kernel.
Refactored dispatch_work() to be cleaner.

104
DESIGN Normal file
View File

@ -0,0 +1,104 @@
Goals:
1. Security
a. Divide into seperate processes that each have the minimal
system access necessary to complete their task.
b. Use a well defined IPC mechanism to facilitate cooperation
between processes. In this case, UNIX domain sockets are
used, since they allow for UNIX DAC (on Linux, at least).
c. Write each program to be secure; don't rely on the
privilege seperations for security.
d. Simple error handling is favored rather than complex error
handling that may possibly be caused to "recover" in an
exploitable way.
e. Don't make stupid assumptions. Implement only the minimal
functionality necessary to perform a task. Expect brain
damaged or malicious inputs.
f. Run inside a chroot, with minimal privileges via
capabilities or MAC.
2. Reliability
a. Don't try to handle severe errors.
b. Log errors if program state is still sane.
c. Recover from predictable problems if necessary. Make sure
that recovery behavior is well understood and defined.
d. Complicated or unsafe recoveries should not be performed;
instead the program should promptly exit. Dead programs
don't cause exploits.
5. Portability
a. Portability is good, but portability may not be as wide as
a less secure program. Capabilities or MAC are not well
standardized, but remain necessary features.
b. Aside from the previous caveat, try to be as portable as
possible. At the very least, the dhcp client daemon
should be easily portable (only broadcast and perhaps RAW
packets are necessary).
98. Speed
a. If we aren't required to sacrifice anything more
important, it's always good to be fast.
99. Size
a. If we aren't required to sacrifice anything more
important, it's always good to be frugal.
Specifics:
Implementation language will be C. C is universally available, very
predictable, and well accepted. dhcp clients don't have to deal with
complicated data structures or extensively with strings, so C's
largest weaknesses should not be highly apparent. On the other hand,
dhcp clients must extensively deal with the OS in a low-level fashion.
C's strongest points will therefore be used.
More practically, a program written in a compiled language other than
C will be poorly accepted by the average user. Since widespread use
is an eventual goal of ndhc, this point is very eloquent.
For now, I'm taking advantage of the existing udhcpc. With minor
modifications, it will serve quite well as the dhcp client daemon. It
is then only necessary for me to write a client request translator
and a interface change daemon. The result should be a highly modular
solution.
I'm developing on a Linux-based platform. ndhc will first be designed
to work properly on a Linux-based system. I will then make certain
that ndhc works well on a RSBAC-enabled Linux system. Afterwards, I
_may_ spend some effort porting ndhc to FreeBSD (but don't count on it). I
have no personal interest in other platforms.
Layout:
ndhc daemon (root -> chroot -> drop all !(CAP_NET_BROADCAST|CAP_NET_RAW)
-> nopriv)
* handles dhcp protocol issues
* keeps track of leases
* talks to ndhif to perform tasks that require
higher privileges than CAP_NET_BROADCAST or CAP_NET_RAW
ifchd daemon (root -> openfd -> chroot -> drop all !CAP_NET_ADMIN -> nopriv)
* listens for interface change requests via UNIX domain socket
* restricts valid IP ranges that will be accepted
* performs interface changes
* keeps rw fds for system files (such as /etc/resolv.conf) that must
be modified outside the chroot

339
LICENSE Normal file
View File

@ -0,0 +1,339 @@
GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.) You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get the
source code. And you must show them these terms so they know their
rights.
We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software. If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.
Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary. To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and
modification follow.
GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. The "Program", below,
refers to any such program or work, and a "work based on the Program"
means either the Program or any derivative work under copyright law:
that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another
language. (Hereinafter, translation is included without limitation in
the term "modification".) Each licensee is addressed as "you".
Activities other than copying, distribution and modification are not
covered by this License; they are outside its scope. The act of
running the Program is not restricted, and the output from the Program
is covered only if its contents constitute a work based on the
Program (independent of having been made by running the Program).
Whether that is true depends on what the Program does.
1. You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty;
and give any other recipients of the Program a copy of this License
along with the Program.
You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.
2. You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:
a) You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.
b) You must cause any work that you distribute or publish, that in
whole or in part contains or is derived from the Program or any
part thereof, to be licensed as a whole at no charge to all third
parties under the terms of this License.
c) If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display an
announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
these conditions, and telling the user how to view a copy of this
License. (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works. But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
exercise the right to control the distribution of derivative or
collective works based on the Program.
In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
the scope of this License.
3. You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:
a) Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections
1 and 2 above on a medium customarily used for software interchange; or,
b) Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; or,
c) Accompany it with the information you received as to the offer
to distribute corresponding source code. (This alternative is
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with such
an offer, in accord with Subsection b above.)
The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable. However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.
If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.
4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.
5. You are not required to accept this License, since you have not
signed it. However, nothing else grants you permission to modify or
distribute the Program or its derivative works. These actions are
prohibited by law if you do not accept this License. Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.
6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions. You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.
7. If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent issues),
conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License. If you cannot
distribute so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you
may not distribute the Program at all. For example, if a patent
license would not permit royalty-free redistribution of the Program by
all those who receive copies directly or indirectly through you, then
the only way you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.
If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.
It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices. Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.
This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License incorporates
the limitation as if written in the body of this License.
9. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time. Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.
Each version is given a distinguishing version number. If the Program
specifies a version number of this License which applies to it and "any
later version", you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation. If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.
10. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission. For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this. Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.
NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS
Appendix: How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) 19yy <name of author>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 19yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.
You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library. If this is what you want to do, use the GNU Library General
Public License instead of this License.

28
Makefile Normal file
View File

@ -0,0 +1,28 @@
CC = gcc -Wall -Wpointer-arith -Wstrict-prototypes
AR = ar
objects = log.o nstrl.o chroot.o pidfile.o signals.o strlist.o linux.o ifchd.o
ifchd : $(objects)
$(CC) -lcap -o ifchd $(objects)
ifchd.o : log.h nstrl.h chroot.h pidfile.h signals.h strlist.h linux.h
$(CC) $(CFLAGS) $(archflags) $(LDFLAGS) -c -o $@ ifchd.c
linux.o: log.h strlist.h
chroot.o: log.h
pidfile.o: log.h
signals.o: log.h
strlist.o:
nstrl.o:
log.o :
install: ifchd
-install -s -m 755 ifchd /usr/sbin/ifchd
tags:
-ctags -f tags *.[ch]
-cscope -b
clean:
-rm -f *.o ifchd
distclean:
-rm -f *.o ifchd tags cscope.out

191
README.ifchd Normal file
View File

@ -0,0 +1,191 @@
ifchd, copyright (c) 2004 Nicholas Kain. Licensed under GNU GPL.
Requirements:
Linux kernel (tested: 2.4, 2.6)
* libcap is required (available via ftp.kernel.org)
C99-compliant C compiler (for C99 struct subobject init)
* any modern GCC should be sufficient
Tested with glibc 2.2.x and 2.3.x. dietlibc is not compatible. I have not yet
tested uclibc.
I may bother to port to other operating systems, but don't count on it. Other
OSes lack the functionality of a [RSBAC|SELinux]+PaX enabled kernel, so I find
them to be less useful for a highly secured system.
INTRODUCTION
------------
ndhc consists of a set of daemons that cooperate in order to provide
privilege-seperated dhcp client services. Each daemon runs with the minimal
necessary privileges in order to perform its task. Currently, ndhc consists of
two daemons: the eponymous ndhc and ifchd.
ndhc communicates with dhcp servers and handles the vagaries of the dhcp
client protocol. It runs as a non-root user inside a chroot. ndhc retains
only the minimum necessary set of privileges required to perform its duties.
These powers include the ability to bind to a low port, the ability to open a
raw socket, and the ability to communicate on broadcast channels. ndhc holds
no other powers and is restricted to a chroot that contains nothing more than a
domain socket filesystem object and (at least on Linux) a urandom device node.
ifchd handles interface change requests. It listens on a UNIX domain socket
for such requests, and denies any client that does not match an authorized gid,
uid, or pid. ifchd runs as a non-root user inside a chroot, and retains only
the power to configure network interfaces. ifchd is designed so that it has
the ability to service multiple client requests simultaneously; a single ifchd
is sufficient for multiple ndhc clients. Only exotic setups should require
this functionality, but it does exist.
Note that ndhc does not support the entire DHCP client protocol. Only the
minimum necessary featureset is implemented. This behavior should be familiar
to anyone who has used software that purports to be be secure.
Many of the features that ndhc depends upon are not entirely standard and vary
between UNIX systems. It is likely that some effort will be required in order
to port ndhc to new systems. The ndhc daemon should be entirely portable aside
from its use of Linux-style POSIX capabilities.
ifchd is necessarily less portable, since it must use system-specific ioctls in
order to configure network interfaces. Additionally, ifchd uses extensions to
the UNIX domain socket family to limit connections to user defined subsets of
possible uids, gids, and pids. These extensions are present in Linux and BSD,
although both Linux and BSD have different interfaces for the functionality.
Patches that provide support for new systems are welcome.
USAGE
-----
1) Compile and install ifchd and ndhc.
a) Build ifchd with "make"
b) Enter ndhc directory and build ndhc with "make"
c) Install the ifchd and ndhc executables in a normal place. I would
suggest /usr/sbin or /usr/local/sbin.
2) Time to create the jail in which ifchd and ndhc will run.
a) Become root and create new group "ifchd".
$ su -
# umask 077
# groupadd ifchd
b) Create new users "ifchd" and "dhcp". The primary group of these
users should be "ifchd".
# useradd -d /var/lib/ndhc -g ifchd ifchd
# useradd -d /var/lib/ndhc -g ifchd dhcp
b) Create the jail directory and set its ownership properly.
# mkdir /var/lib/ndhc
# chown ifchd.ifchd /var/lib/ndhc
# chmod a+rx /var/lib/ndhc
c) Create a urandom device for ndhc to use within the jail.
# cd /var/lib/ndhc
# mkdir dev
# mknod dev/urandom c 1 9
# chown -R root.root dev
# chmod a+rx dev
# chmod a+r dev/urandom
d) (optional) If you wish for logging to properly work, you
will need to properly configure your logging daemon so that it
opens a domain socket in the proper location within the jail.
Since this varies per-daemon, I cannot provide a general
configuration.
3) At this point the jail is usable; ifchd and ndhc are ready to
be used. As an example of a sample configuration, here is my
rc.dhcp:
--START--
#!/bin/sh
case "$1" in
start)
ifchd -i eth0 -p /var/run/ifchd.pid -u ifchd -g ifchd -U dhcp -G ifchd \
-c /var/lib/ndhc &> /dev/null
ndhc -b -i eth0 -u dhcp -C /var/lib/ndhc &> /dev/null
;;
stop)
killall ndhc ifchd
;;
esac
--END--
This script works fine with my personal machines, which are set up
exactly as I have outlined above. If you have not entirely followed my
directions, the script will of course require modifications.
4o) If you encounter problems, I suggest running both ifchd and ndhc in the
foreground, and perhaps compiling ndhc with extra debugging output
(uncomment DEBUG=1 in the Makefile).
BEHAVIOR NOTES
--------------
ifchd does not enable updates of the local hostname and resolv.conf by default.
If you wish to enable these functions, use the --resolve (-r) and --hostname
(-o) flags. See ifchd --help.
ifchd can be set such that it only allows clients to configure particular
network interfaces. The --interface (-i) argument does the trick, and may
be used multiple times to allow multiple interfaces.
RSBAC NOTES
-----------
I was personally unable to get ifchd to properly function with RSBAC_NET_DEV
enabled. Browsing the rsbac source, I was unable to figure out what I was
doing incorrectly -- my RC definitions were as far as I could tell, correct.
Therefore, my directions assume that you have disabled RSBAC_NET_DEV in your
kernel configuration.
The normal usage directions may be followed, but an additional step for rsbac
is necessary. Change to your secoff account and invoke rsbac_fd_menu on the
ifchd and ndhc executables. The AUTH capability for your ifchd and dhcp groups
must be allowed on the corresponding executables, otherwise ifchd and ndhc will
be unable to change to a non-root user and will refuse to run.
GRSECURITY NOTES
----------------
Make sure that CONFIG_GRKERNSEC_CHROOT_CAPS is disabled. Otherwise, ifchd will
lose its capabilities (in particular, the ability to reconfigure interfaces)
when it chroots.
PORTING NOTES
-------------
Unportable functions are isolated to linux.c. Any attempts to port ifchd to
other platforms should isolate platform-dependent code to similarly named
compilation units (eg: for FreeBSD, freebsd.[ch]).
There are four major functions that ifchd depends upon that are not generally
portable. First, it uses the SO_PEERCRED flag of getsockopt() to discriminate
authorized connections by uid, gid, and pid. Similar functionality exists in
at least the BSDs; however, it has a different API. Second, ifchd takes
advantage of Linux capabilities so that it does not need full root privileges.
Capabilities are supposedly a POSIX feature, but in practice, they vary greatly
from system to system. Third and fourth, ifchd configures network interfaces
and routes. Interface and route configuration is entirely non-portable,
usually requiring calls to the catch-all ioctl(), and will almost certainly
require platform-dependent code.
Some standard C libraries include a native implementation of strlcpy() and
strlcat(). Such defines may conflict with my implementations in
nstrl.c/nstrl.h. It is up to the user whether the standard C library
implementations should be used. Note that some machines implement strlcpy()
and strlcat() with nonstandard semantics (notably Solaris). On these systems,
using the system-provided implementations may lead to security problems. Such
problems are the fault of the vendor. If you are unsure whether your system is
correct or not, I suggest using the implementation that I provide.

3
TODO Normal file
View File

@ -0,0 +1,3 @@
write documentation...
support BSD

42
chroot.c Normal file
View File

@ -0,0 +1,42 @@
/* chroot.c - chroots ncron jobs
(C) 2003 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <unistd.h>
#include <stdlib.h>
#include "log.h"
void imprison(char *path)
{
int ret;
if (path == NULL)
return;
ret = chdir(path);
if (ret) {
log_line("Failed to chdir(%s). Not invoking job.", path);
exit(EXIT_FAILURE);
}
ret = chroot(path);
if (ret) {
log_line("Failed to chroot(%s). Not invoking job.", path);
exit(EXIT_FAILURE);
}
}

21
chroot.h Normal file
View File

@ -0,0 +1,21 @@
/* chroot.h - include file for chroot.c
(C) 2003 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef NJK_CHROOT_H_
#define NJK_CHROOT_H_ 1
void imprison(char *path);
#endif

12
defines.h Normal file
View File

@ -0,0 +1,12 @@
#define MAX_PATH_LENGTH 1024
#define PID_FILE_DEFAULT "/var/run/ifchd.pid"
#define IFCHD_VERSION "0.8"
#define COMM_SOCKET_PATH "ifchange"
#define MAX_BUF 1024
#define MAXLINE 1024
#define SOCK_QUEUE 2
#define CONN_TIMEOUT 60
#define LINUX 1

916
ifchd.c Normal file
View File

@ -0,0 +1,916 @@
/* ifchd.c - interface change daemon
* Time-stamp: <2004-06-14 njk>
*
* (C) 2004 Nicholas J. Kain <njk@aerifal.cx>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <signal.h>
#include <errno.h>
#define _GNU_SOURCE
#include <getopt.h>
#include "defines.h"
#include "log.h"
#include "chroot.h"
#include "pidfile.h"
#include "signals.h"
#include "strlist.h"
#include "ifproto.h"
#include "nstrl.h"
#include "linux.h"
enum states {
STATE_NOTHING,
STATE_INTERFACE,
STATE_IP,
STATE_SUBNET,
STATE_TIMEZONE,
STATE_ROUTER,
STATE_TIMESVR,
STATE_DNS,
STATE_LPRSVR,
STATE_HOSTNAME,
STATE_DOMAIN,
STATE_IPTTL,
STATE_MTU,
STATE_BROADCAST,
STATE_NTPSRV,
STATE_WINS
};
static volatile sig_atomic_t pending_exit;
/* Socket fd, current state, and idle time for connections. */
static int sks[SOCK_QUEUE], state[SOCK_QUEUE], idle_time[SOCK_QUEUE];
/* Per-connection buffers. */
static char ibuf[SOCK_QUEUE][MAX_BUF];
/*
* Per-connection pointers into the command lists. Respectively, the
* topmost item on the list, the current item, and the last item on the list.
*/
static strlist_t *head[SOCK_QUEUE], *curl[SOCK_QUEUE], *last[SOCK_QUEUE];
int resolv_conf_fd = -1;
/* int ntp_conf_fd = -1; */
/* If true, allow HOSTNAME changes from dhcp server. */
int allow_hostname = 0;
static uid_t peer_uid;
static gid_t peer_gid;
static pid_t peer_pid;
/* Lists of nameservers and search domains. Unfortunately they must be
* per-connection, since otherwise seperate clients could race against
* one another to write out unpredictable data.
*/
static strlist_t *namesvrs[SOCK_QUEUE];
static strlist_t *domains[SOCK_QUEUE];
static void sighandler(int sig) {
pending_exit = 1;
}
static void fix_signals(void) {
disable_signal(SIGPIPE);
disable_signal(SIGUSR1);
disable_signal(SIGUSR2);
disable_signal(SIGTSTP);
disable_signal(SIGTTIN);
disable_signal(SIGCHLD);
disable_signal(SIGHUP);
hook_signal(SIGINT, sighandler, 0);
hook_signal(SIGTERM, sighandler, 0);
}
static void suicide(char *errmsg, const char *perrmsg, int status)
{
if (errmsg)
log_line(errmsg);
if (!gflags_detach && perrmsg)
perror(perrmsg);
exit(status);
}
static void die_nulstr(strlist_t *p)
{
if (!p)
suicide("FATAL - NULL passed to die_nulstr\n", NULL, EXIT_FAILURE);
if (!p->str)
suicide("FATAL - NULL string in strlist\n", NULL, EXIT_FAILURE);
}
/* Writes out each element in a strlist as an argument to a keyword in
* a file. */
static void write_resolve_list(const char *keyword, strlist_t *list)
{
char *buf;
strlist_t *p = list;
unsigned int len;
if (!keyword || resolv_conf_fd == -1)
return;
while (p) {
buf = p->str;
len = strlen(buf);
if (len) {
write(resolv_conf_fd, keyword, strlen(keyword));
write(resolv_conf_fd, buf, strlen(buf));
write(resolv_conf_fd, "\n", 1);
}
p = p->next;
}
}
/* Writes a new resolv.conf based on the information we have received. */
static void write_resolve_conf(int idx)
{
off_t off;
if (resolv_conf_fd == -1)
return;
if (lseek(resolv_conf_fd, 0, SEEK_SET) == -1)
return;
write_resolve_list("nameserver ", namesvrs[idx]);
write_resolve_list("search ", domains[idx]);
off = lseek(resolv_conf_fd, 0, SEEK_CUR);
if (off == -1) {
log_line("write_resolve_conf: lseek returned error: %s\n",
strerror(errno));
return;
}
ftruncate(resolv_conf_fd, off);
fsync(resolv_conf_fd);
}
/* Decomposes a ' '-delimited flat character array onto a strlist, then
* calls the given function to perform work on the generated strlist. */
static void parse_list(int idx, char *str, strlist_t **toplist,
void (*fn)(int))
{
char *p, n[256];
unsigned int i;
strlist_t *newn = 0;
if (!str || !toplist || !fn)
return;
p = str;
while (p != '\0') {
memset(n, '\0', sizeof n);
for (i = 0; i < sizeof n - 1 && *p != '\0' && *p != ' '; ++p, ++i)
n[i] = *p;
if (*p == ' ')
++p;
add_to_strlist(n, &newn);
}
if (newn) {
free_strlist(*toplist);
*toplist = newn;
} else
return;
(*fn)(idx);
}
/* XXX: addme */
static void perform_timezone(int idx, char *str)
{}
/* Does anyone use this command? */
static void perform_timesvr(int idx, char *str)
{}
/* Add a dns server to the /etc/resolv.conf -- we already have a fd. */
static void perform_dns(int idx, char *str)
{
if (!str || resolv_conf_fd == -1)
return;
parse_list(idx, str, &(namesvrs[idx]), &write_resolve_conf);
}
/* Updates for print daemons are too non-standard to be useful. */
static void perform_lprsvr(int idx, char *str)
{}
/* Sets machine hostname. */
static void perform_hostname(int idx, char *str)
{
if (!allow_hostname || !str)
return;
if (sethostname(str, strlen(str) + 1) == -1)
log_line("sethostname returned %s\n", strerror(errno));
}
/* update "search" in /etc/resolv.conf */
static void perform_domain(int idx, char *str)
{
if (!str || resolv_conf_fd == -1)
return;
parse_list(idx, str, &(domains[idx]), &write_resolve_conf);
}
/* I don't think this can be done without a netfilter extension
* that isn't in the mainline kernels. */
static void perform_ipttl(int idx, char *str)
{}
/* XXX: addme */
static void perform_ntpsrv(int idx, char *str)
{}
/* Maybe Samba cares about this feature? I don't know. */
static void perform_wins(int idx, char *str)
{}
/* Wipes all state associated with a given connection. */
static void new_sk(int idx, int val)
{
sks[idx] = val;
memset(ibuf[idx], '\0', sizeof(ibuf[idx]));
free_strlist(head[idx]);
free_strlist(namesvrs[idx]);
free_strlist(domains[idx]);
head[idx] = NULL;
curl[idx] = NULL;
last[idx] = NULL;
namesvrs[idx] = NULL;
domains[idx] = NULL;
idle_time[idx] = time(NULL);
state[idx] = STATE_NOTHING;
clear_if_data(idx);
}
/* Conditionally accepts a new connection and initializes data structures. */
static void add_sk(int sk)
{
int i;
if (authorized_peer(sk, peer_pid, peer_uid, peer_gid)) {
for (i=0; i<SOCK_QUEUE; i++)
if (sks[i] == -1) {
new_sk(i, sk);
return;
}
}
close(sk);
}
/* Closes idle connections. */
static void close_idle_sk(void)
{
int i;
for (i=0; i<SOCK_QUEUE; i++) {
if (sks[i] == -1)
continue;
if (time(NULL) - idle_time[i] > CONN_TIMEOUT) {
close(sks[i]);
new_sk(i, -1);
}
}
}
/* Decomposes a ':'-delimited flat character array onto a strlist. */
static int stream_onto_list(int i)
{
int e, s;
for (e = 0, s = 0; ibuf[i][e] != '\0'; e++) {
if (ibuf[i][e] == ':') {
/* Zero-length command: skip. */
if (s == e) {
s = e + 1;
continue;
}
curl[i] = malloc(sizeof(strlist_t));
if (curl[i] == NULL)
suicide("FATAL - malloc failed\n", "malloc",
EXIT_FAILURE);
if (head[i] == NULL) {
head[i] = curl[i];
last[i] = NULL;
}
curl[i]->next = NULL;
if (last[i] != NULL)
last[i]->next = curl[i];
curl[i]->str = malloc(e - s + 1);
if (curl[i]->str == NULL)
suicide("FATAL - malloc failed\n", "malloc",
EXIT_FAILURE);
strlcpy(curl[i]->str, ibuf[i] + s, e - s);
last[i] = curl[i];
s = e + 1;
}
}
return s;
}
/* State machine that runs over the command and argument list,
* executing commands. */
static void execute_list(int i)
{
char *p;
for (;;) {
if (!curl[i])
break;
die_nulstr(curl[i]);
p = curl[i]->str;
switch (state[i]) {
case STATE_NOTHING:
if (strncmp(p, CMD_INTERFACE, sizeof(CMD_INTERFACE)) == 0)
state[i] = STATE_INTERFACE;
if (strncmp(p, CMD_IP, sizeof(CMD_IP)) == 0)
state[i] = STATE_IP;
if (strncmp(p, CMD_SUBNET, sizeof(CMD_SUBNET)) == 0)
state[i] = STATE_SUBNET;
if (strncmp(p, CMD_TIMEZONE, sizeof(CMD_TIMEZONE)) == 0)
state[i] = STATE_TIMEZONE;
if (strncmp(p, CMD_ROUTER, sizeof(CMD_ROUTER)) == 0)
state[i] = STATE_ROUTER;
if (strncmp(p, CMD_TIMESVR, sizeof(CMD_TIMESVR)) == 0)
state[i] = STATE_TIMESVR;
if (strncmp(p, CMD_DNS, sizeof(CMD_DNS)) == 0)
state[i] = STATE_DNS;
if (strncmp(p, CMD_LPRSVR, sizeof(CMD_LPRSVR)) == 0)
state[i] = STATE_LPRSVR;
if (strncmp(p, CMD_HOSTNAME, sizeof(CMD_HOSTNAME)) == 0)
state[i] = STATE_HOSTNAME;
if (strncmp(p, CMD_DOMAIN, sizeof(CMD_DOMAIN)) == 0)
state[i] = STATE_DOMAIN;
if (strncmp(p, CMD_IPTTL, sizeof(CMD_IPTTL)) == 0)
state[i] = STATE_IPTTL;
if (strncmp(p, CMD_MTU, sizeof(CMD_MTU)) == 0)
state[i] = STATE_MTU;
if (strncmp(p, CMD_BROADCAST, sizeof(CMD_BROADCAST)) == 0)
state[i] = STATE_BROADCAST;
if (strncmp(p, CMD_NTPSRV, sizeof(CMD_NTPSRV)) == 0)
state[i] = STATE_NTPSRV;
if (strncmp(p, CMD_WINS, sizeof(CMD_WINS)) == 0)
state[i] = STATE_WINS;
free_stritem(&(curl[i]));
break;
case STATE_INTERFACE:
perform_interface(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_IP:
perform_ip(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_SUBNET:
perform_subnet(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_TIMEZONE:
perform_timezone(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_ROUTER:
perform_router(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_TIMESVR:
perform_timesvr(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_DNS:
perform_dns(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_LPRSVR:
perform_lprsvr(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_HOSTNAME:
perform_hostname(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_DOMAIN:
perform_domain(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_IPTTL:
perform_ipttl(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_MTU:
perform_mtu(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_BROADCAST:
perform_broadcast(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_NTPSRV:
perform_ntpsrv(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
case STATE_WINS:
perform_wins(i, p);
free_stritem(&(curl[i]));
state[i] = STATE_NOTHING;
break;
default:
log_line("warning: invalid state in dispatch_work\n");
break;
}
}
head[i] = curl[i];
}
/* Opens a non-blocking listening socket with the appropriate properties. */
static int get_listen(void)
{
int lsock, ret;
struct sockaddr_un lsock_addr =
{
.sun_family = AF_UNIX,
.sun_path = COMM_SOCKET_PATH
};
lsock = socket(PF_UNIX, SOCK_STREAM, 0);
if (lsock == -1)
suicide("FATAL - failed to create socket\n",
"dispatch_work - socket", EXIT_FAILURE);
fcntl(lsock, F_SETFL, O_NONBLOCK);
(void) unlink(COMM_SOCKET_PATH);
ret = bind(lsock, (struct sockaddr *) &lsock_addr, sizeof(lsock_addr));
if (ret)
suicide("FATAL - failed to bind socket\n",
"dispatch_work - bind", EXIT_FAILURE);
ret = chmod(COMM_SOCKET_PATH, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
if (ret)
suicide("FATAL - failed to chmod socket\n",
"dispatch_work - chmod", EXIT_FAILURE);
ret = listen(lsock, SOCK_QUEUE);
if (ret)
suicide("FATAL - failed to listen on socket\n",
"dispatch_work - listen", EXIT_FAILURE);
return lsock;
}
/* Abstracts away the details of accept()ing a socket connection. */
static void accept_conns(int *lsock)
{
int ret;
struct sockaddr_un sock_addr;
socklen_t sock_len = sizeof(sock_addr);
for(;;)
{
ret = accept(*lsock, (struct sockaddr *) &sock_addr, &sock_len);
if (ret != -1) {
add_sk(ret);
return;
}
switch (errno) {
case EAGAIN:
#ifdef LINUX
case ENETDOWN:
case EPROTO:
case ENOPROTOOPT:
case EHOSTDOWN:
case ENONET:
case EHOSTUNREACH:
case EOPNOTSUPP:
case ENETUNREACH:
#endif
return;
case EINTR:
continue;
case EBADF:
case ENOTSOCK:
case EINVAL:
log_line("warning: accept returned %s!\n", strerror(errno));
close(*lsock);
*lsock = get_listen();
return;
case ECONNABORTED:
case EMFILE:
case ENFILE:
log_line("warning: accept returned %s!\n", strerror(errno));
return;
default:
log_line("warning: accept returned a mysterious error: %s\n",
strerror(errno));
return;
}
}
}
/* Core function that handles connections, gathers input, and calls
* the state machine to do actual work. */
static void dispatch_work(void)
{
int lsock, ret, highfd, i, index;
fd_set rfds;
char buf[MAX_BUF];
/* Initialize all structures to blank state. */
for (i=0; i<SOCK_QUEUE; i++)
sks[i] = -1;
initialize_if_data();
lsock = get_listen();
for (;;) {
FD_ZERO(&rfds);
FD_SET(lsock, &rfds);
/* find highest fd */
for (i=0, highfd=0; i<SOCK_QUEUE; i++) {
if (sks[i] != -1) {
FD_SET(sks[i], &rfds);
if (sks[i] > highfd)
highfd = sks[i];
}
}
if (lsock > highfd)
highfd = lsock;
ret = select(highfd + 1, &rfds, NULL, NULL, NULL);
switch (ret) {
case 0:
close_idle_sk();
break;
case -1:
if (pending_exit == 1)
return;
suicide("FATAL - select returned an error!\n",
"dispatch_work - select", EXIT_FAILURE);
break;
}
if (pending_exit == 1)
return;
/* handle pending connections */
if (FD_ISSET(lsock, &rfds))
accept_conns(&lsock);
/* Read in and process data on waiting connections */
for (i=0; i<SOCK_QUEUE; i++) {
if (sks[i] == -1)
continue;
if (!FD_ISSET(sks[i], &rfds))
continue;
idle_time[i] = time(NULL);
memset(buf, '\0', sizeof(buf));
dispatch_work_read_again:
ret = (int) read(sks[i], buf, MAX_BUF / 2 - 1);
/* Check to see if peer closed socket */
if (ret == 0) {
close(sks[i]);
new_sk(i, -1);
continue;
}
if (ret == -1) {
if (errno == EINTR)
goto dispatch_work_read_again;
log_line("dispatch_work: read returned %s.\n", strerror(errno));
close(sks[i]);
new_sk(i, -1);
continue;
}
/* Discard everything and close connection if we risk overflow.
* This approach is maximally conservative... worst case is that
* some client requests will get dropped. */
index = strlen(ibuf[i]);
if (index + strlen(buf) > MAX_BUF - 2) {
close(sks[i]);
new_sk(i, -1);
continue;
}
/* Append new stream input avoiding overflow. */
strlcpy(ibuf[i] + index, buf, sizeof(ibuf[i]) - index - 1);
/* Decompose ibuf contents onto strlist. */
index = stream_onto_list(i);
/* Remove everything that we've parsed into the list. */
strlcpy(buf, ibuf[i] + index, sizeof(buf));
strlcpy(ibuf[i], buf, sizeof(ibuf[i]));
/* Now we have a strlist of commands and arguments.
* Decompose and execute it. */
if (!head[i])
continue;
curl[i] = head[i];
execute_list(i);
}
close_idle_sk();
}
}
int main(int argc, char** argv) {
int c, t, uid = 0, gid = 0;
char pidfile[MAX_PATH_LENGTH] = PID_FILE_DEFAULT;
char chrootd[MAX_PATH_LENGTH] = "";
char resolv_conf_d[MAX_PATH_LENGTH] = "";
char *p;
struct passwd *pws;
struct group *grp;
while (1) {
int option_index = 0;
static struct option long_options[] = {
{"detach", 0, 0, 'd'},
{"nodetach", 0, 0, 'n'},
{"pidfile", 1, 0, 'p'},
{"quiet", 0, 0, 'q'},
{"chroot", 1, 0, 'c'},
{"resolve", 1, 0, 'r'},
{"hostname", 0, 0, 'o'},
{"user", 1, 0, 'u'},
{"group", 1, 0, 'g'},
{"cuser", 1, 0, 'U'},
{"cgroup", 1, 0, 'G'},
{"cpid", 1, 0, 'P'},
{"interface", 1, 0, 'i'},
{"help", 0, 0, 'h'},
{"version", 0, 0, 'v'},
{0, 0, 0, 0}
};
c = getopt_long(argc, argv, "dnp:qc:r:ou:g:U:G:P:i:hv", long_options,
&option_index);
if (c == -1)
break;
switch (c) {
case 'h':
printf(
"ifchd %s, if change daemon. Licensed under GNU GPL.\n", IFCHD_VERSION);
printf(
"Copyright (C) 2004 Nicholas J. Kain\n"
"Usage: ifchd [OPTIONS]\n"
" -d, --detach detach from TTY and daemonize\n"
" -n, --nodetach stay attached to TTY\n"
" -q, --quiet don't print to std(out|err) or log\n"
" -c, --chroot path where ifchd should chroot\n"
" -r, --resolve path to resolv.conf or equiv\n"
" -o, --hostname allow dhcp to set machine hostname\n"
" -p, --pidfile pidfile path\n");
printf(
" -u, --user user name that ifchd should run as\n"
" -g, --group group name that ifchd should run as\n"
" -U, --cuser user name of clients\n"
" -G, --cgroup group name of clients\n"
" -P, --cpid process id of client\n"
" -i, --interface ifchd clients may modify this interface\n"
" -h, --help print this help and exit\n"
" -v, --version print version information and exit\n");
exit(EXIT_FAILURE);
break;
case 'v':
printf(
"ifchd %s, if change daemon. Licensed under GNU GPL.\n", IFCHD_VERSION);
printf(
"Copyright (C) 2004 Nicholas J. Kain\n"
"This is free software; see the source for copying conditions. There is NO\n"
"WARRANTY; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n");
exit(EXIT_FAILURE);
break;
case 'd':
gflags_detach = 1;
break;
case 'n':
gflags_detach = 0;
break;
case 'q':
gflags_quiet = 1;
break;
case 'c':
strlcpy(chrootd, optarg, MAX_PATH_LENGTH);
break;
case 'p':
strlcpy(pidfile, optarg, MAX_PATH_LENGTH);
break;
case 'r':
strlcpy(resolv_conf_d, optarg, MAX_PATH_LENGTH);
break;
case 'o':
allow_hostname = 1;
break;
case 'u':
t = (unsigned int) strtol(optarg, &p, 10);
if (*p != '\0') {
pws = getpwnam(optarg);
if (pws) {
uid = (int)pws->pw_uid;
if (!gid)
gid = (int)pws->pw_gid;
} else suicide("FATAL - Invalid uid specified.\n", NULL,
EXIT_FAILURE);
} else
uid = t;
break;
case 'g':
t = (unsigned int) strtol(optarg, &p, 10);
if (*p != '\0') {
grp = getgrnam(optarg);
if (grp) {
gid = (int)grp->gr_gid;
} else suicide("FATAL - Invalid gid specified.\n", NULL,
EXIT_FAILURE);
} else
gid = t;
break;
case 'U':
t = (unsigned int) strtol(optarg, &p, 10);
if (*p != '\0') {
pws = getpwnam(optarg);
if (pws) {
peer_uid = (int)pws->pw_uid;
if (!peer_gid)
peer_gid = (int)pws->pw_gid;
} else suicide("FATAL - Invalid uid specified.\n", NULL,
EXIT_FAILURE);
} else
peer_uid = t;
break;
case 'G':
t = (unsigned int) strtol(optarg, &p, 10);
if (*p != '\0') {
grp = getgrnam(optarg);
if (grp) {
peer_gid = (int)grp->gr_gid;
} else suicide("FATAL - Invalid gid specified.\n", NULL,
EXIT_FAILURE);
} else
peer_gid = t;
break;
case 'P':
t = (unsigned int) strtol(optarg, &p, 10);
if (*p == '\0')
peer_pid = t;
break;
case 'i':
add_permitted_if(optarg);
break;
}
}
if (getuid())
suicide("FATAL - I need root for CAP_NET_ADMIN and chroot!\n",
NULL, EXIT_FAILURE);
if (gflags_detach)
if (daemon(0,0)) {
log_line("FATAL - detaching fork failed\n");
exit(EXIT_FAILURE);
}
if (!file_exists(pidfile, "w")) {
log_line("FATAL - cannot open pidfile for write!");
exit(EXIT_FAILURE);
}
write_pid(pidfile);
umask(077);
fix_signals();
/* If we are requested to update resolv.conf, preopen the fd before
* we drop root privileges, making sure that if we create
* resolv.conf, it will be world-readable.
*/
if (strncmp(resolv_conf_d, "", MAX_PATH_LENGTH)) {
umask(022);
resolv_conf_fd = open(resolv_conf_d, O_RDWR | O_CREAT);
umask(077);
if (resolv_conf_fd == -1) {
suicide("FATAL - unable to open resolv.conf\n",
"main - open", EXIT_FAILURE);
}
}
if (!strncmp(chrootd, "", MAX_PATH_LENGTH))
suicide("FATAL - No chroot path specified. Refusing to run.\n",
NULL, EXIT_FAILURE);
/* Note that failure cases are handled by called fns. */
imprison(chrootd);
drop_root(uid, gid, "cap_net_admin=ep");
/* Cover our tracks... */
memset(chrootd, '\0', sizeof(chrootd));
memset(resolv_conf_d, '\0', sizeof(resolv_conf_d));
memset(pidfile, '\0', sizeof(pidfile));
dispatch_work();
/* Explicitly freed so memory debugger output has less static. */
for (c=0; c<SOCK_QUEUE; ++c) {
free_strlist(head[c]);
free_strlist(namesvrs[c]);
free_strlist(domains[c]);
}
exit(EXIT_SUCCESS);
}

20
ifproto.h Normal file
View File

@ -0,0 +1,20 @@
#ifndef NJK_IFPROTO_H__
#define NJK_IFPROTO_H__ 1
#define CMD_INTERFACE "interface"
#define CMD_IP "ip"
#define CMD_SUBNET "subnet"
#define CMD_TIMEZONE "timezone"
#define CMD_ROUTER "router"
#define CMD_TIMESVR "timesvr"
#define CMD_DNS "dns"
#define CMD_LPRSVR "lprsvr"
#define CMD_HOSTNAME "hostname"
#define CMD_DOMAIN "domain"
#define CMD_IPTTL "ipttl"
#define CMD_MTU "mtu"
#define CMD_BROADCAST "broadcast"
#define CMD_NTPSRV "ntpsrv"
#define CMD_WINS "wins"
#endif

394
linux.c Normal file
View File

@ -0,0 +1,394 @@
/* linux.c - ifchd Linux-specific functions
* Time-stamp: <2004-06-14 njk>
*
* (C) 2004 Nicholas J. Kain <njk@aerifal.cx>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define __USE_GNU 1
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/route.h>
#include <net/if.h>
#include <netpacket/packet.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#include "defines.h"
#include "log.h"
#include "strlist.h"
#include "ifproto.h"
#include "nstrl.h"
/* Symbolic name of the interface associated with a connection. */
static char ifnam[SOCK_QUEUE][IFNAMSIZ];
static strlist_t *okif;
/* Clear a specified ifnam structure. */
void clear_if_data(int idx)
{
memset(ifnam[idx], '\0', IFNAMSIZ);
}
/* Clear all ifnam structures. */
void initialize_if_data(void)
{
int i;
for (i = 0; i < SOCK_QUEUE; i++) {
clear_if_data(i);
}
}
/* Adds to the list of interface names ifchd clients are allowed to change. */
void add_permitted_if(char *s)
{
if (!s)
return;
add_to_strlist(s, &okif);
}
/* Checks if changes are permitted to a given interface. 1 == allowed */
static int is_permitted(char *name)
{
strlist_t *p;
/* If empty, permit all. */
if (!okif)
return 1;
if (!name || strlen(name) == 0)
return 0;
p = okif;
while (p) {
if (strcmp(name, p->str) == 0)
return 1;
p = p->next;
}
log_line("attempt to modify interface %s denied\n", name);
return 0;
}
/* Verify that peer is authorized to connect (return 1 on success). */
int authorized_peer(int sk, pid_t pid, uid_t uid, gid_t gid)
{
int ret = 0;
unsigned int cl;
struct ucred cr;
/* No credentials to verify. */
if ( !(pid || uid || gid) )
return 1;
/* Verify that peer has authorized uid/gid/pid. */
cl = sizeof(struct ucred);
if (getsockopt(sk, SOL_SOCKET, SO_PEERCRED, &cr, &cl) != -1) {
if ((pid == 0 || cr.pid == pid) ||
(uid == 0 || cr.uid == uid) ||
(gid == 0 || cr.gid == gid))
ret = 1;
} else
log_line("getsockopt returned an error: %s\n", strerror(errno));
return ret;
}
void perform_interface(int idx, char *str)
{
if (!str)
return;
/* Update interface name. */
memset(ifnam[idx], '\0', IFNAMSIZ);
strlcpy(ifnam[idx], str, IFNAMSIZ);
}
static int set_if_flag(int idx, short flag)
{
int fd, ret = -1;
struct ifreq ifrt;
if (!is_permitted(ifnam[idx]))
goto out0;
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (set_if_flag) failed to open interface socket: %s\n",
ifnam[idx], strerror(errno));
goto out0;
}
strlcpy(ifrt.ifr_name, ifnam[idx], IFNAMSIZ);
if (ioctl(fd, SIOCGIFFLAGS, &ifrt) < 0) {
log_line("%s: unknown interface: %s\n", ifnam[idx], strerror(errno));
goto out1;
}
strlcpy(ifrt.ifr_name, ifnam[idx], IFNAMSIZ);
ifrt.ifr_flags |= flag;
if (ioctl(fd, SIOCSIFFLAGS, &ifrt) < 0) {
log_line("%s: failed to set interface flags: %s\n",
ifnam[idx], strerror(errno));
goto out1;
}
ret = 0;
out1:
close(fd);
out0:
return ret;
}
/* Sets IP address on an interface and brings it up. */
void perform_ip(int idx, char *str)
{
int fd;
struct in_addr ipaddr;
struct ifreq ifrt;
struct sockaddr_in sin;
if (!str)
return;
if (!is_permitted(ifnam[idx]))
return;
if (!inet_aton(str, &ipaddr))
return;
if (set_if_flag(idx, (IFF_UP | IFF_RUNNING)))
return;
strlcpy(ifrt.ifr_name, ifnam[idx], IFNAMSIZ);
memset(&sin, 0, sizeof(struct sockaddr));
sin.sin_family = AF_INET;
sin.sin_addr = ipaddr;
memcpy(&ifrt.ifr_addr, &sin, sizeof(struct sockaddr));
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (perform_ip) failed to open interface socket: %s\n",
ifnam[idx], strerror(errno));
return;
}
if (ioctl(fd, SIOCSIFADDR, &ifrt) < 0)
log_line("%s: failed to configure IP: %s\n",
ifnam[idx], strerror(errno));
close(fd);
}
/* Sets the subnet mask on an interface. */
void perform_subnet(int idx, char *str)
{
int fd;
struct in_addr subnet;
struct ifreq ifrt;
struct sockaddr_in sin;
if (!str)
return;
if (!is_permitted(ifnam[idx]))
return;
if (!inet_aton(str, &subnet))
return;
strlcpy(ifrt.ifr_name, ifnam[idx], IFNAMSIZ);
memset(&sin, 0, sizeof(struct sockaddr));
sin.sin_family = AF_INET;
sin.sin_addr = subnet;
memcpy(&ifrt.ifr_addr, &sin, sizeof(struct sockaddr));
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (perform_ip) failed to open interface socket: %s\n",
ifnam[idx], strerror(errno));
return;
}
if (ioctl(fd, SIOCSIFNETMASK, &ifrt) < 0) {
sin.sin_addr.s_addr = 0xffffffff;
if (ioctl(fd, SIOCSIFNETMASK, &ifrt) < 0)
log_line("%s: failed to configure subnet: %s\n",
ifnam[idx], strerror(errno));
}
close(fd);
}
void perform_router(int idx, char *str)
{
struct rtentry rt;
struct sockaddr_in *dest;
struct sockaddr_in *gateway;
struct sockaddr_in *mask;
struct in_addr router;
int fd;
if (!str)
return;
if (!is_permitted(ifnam[idx]))
return;
if (!inet_aton(str, &router))
return;
memset(&rt, 0, sizeof(struct rtentry));
dest = (struct sockaddr_in *) &rt.rt_dst;
dest->sin_family = AF_INET;
dest->sin_addr.s_addr = 0x00000000;
gateway = (struct sockaddr_in *) &rt.rt_gateway;
gateway->sin_family = AF_INET;
gateway->sin_addr = router;
mask = (struct sockaddr_in *) &rt.rt_genmask;
mask->sin_family = AF_INET;
mask->sin_addr.s_addr = 0x00000000;
rt.rt_flags = RTF_UP | RTF_GATEWAY;
if (mask->sin_addr.s_addr == 0xffffffff) rt.rt_flags |= RTF_HOST;
rt.rt_dev = ifnam[idx];
rt.rt_metric = 1;
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (perform_router) failed to open interface socket: %s\n",
ifnam[idx], strerror(errno));
return;
}
if (ioctl(fd, SIOCADDRT, &rt))
log_line("%s: failed to set route: %s\n", ifnam[idx], strerror(errno));
close(fd);
}
void perform_mtu(int idx, char *str)
{
int fd;
unsigned int mtu;
struct ifreq ifrt;
if (!str)
return;
if (!is_permitted(ifnam[idx]))
return;
mtu = strtol(str, NULL, 10);
ifrt.ifr_mtu = mtu;
strlcpy(ifrt.ifr_name, ifnam[idx], IFNAMSIZ);
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (perform_mtu) failed to open interface socket: %s\n",
ifnam[idx], strerror(errno));
return;
}
if (ioctl(fd, SIOCSIFMTU, &ifrt) < 0)
log_line("%s: failed to set MTU (%d): %s\n", ifnam[idx], mtu,
strerror(errno));
close(fd);
}
void perform_broadcast(int idx, char *str)
{
int fd;
struct in_addr broadcast;
struct ifreq ifrt;
struct sockaddr_in sin;
if (!str)
return;
if (!is_permitted(ifnam[idx]))
return;
if (!inet_aton(str, &broadcast))
return;
strlcpy(ifrt.ifr_name, ifnam[idx], IFNAMSIZ);
memset(&sin, 0, sizeof(struct sockaddr));
sin.sin_family = AF_INET;
sin.sin_addr = broadcast;
memcpy(&ifrt.ifr_addr, &sin, sizeof(struct sockaddr));
fd = socket(PF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (perform_broadcast) failed to open interface socket: %s\n", ifnam[idx], strerror(errno));
return;
}
if (ioctl(fd, SIOCSIFBRDADDR, &ifrt) < 0)
log_line("%s: failed to set broadcast: %s\n",
ifnam[idx], strerror(errno));
close(fd);
}
static void set_cap(uid_t uid, gid_t gid, char *captxt)
{
cap_t caps;
if (!captxt) {
log_line("FATAL - set_cap: captxt == NULL\n");
exit(EXIT_FAILURE);
}
if (prctl(PR_SET_KEEPCAPS, 1)) {
log_line("FATAL - set_cap: prctl() failed\n");
exit(EXIT_FAILURE);
}
if (setgroups(0, NULL) == -1) {
log_line("FATAL - set_cap: setgroups() failed\n");
exit(EXIT_FAILURE);
}
if (setegid(gid) == -1 || seteuid(uid) == -1) {
log_line("FATAL - set_cap: seteuid() failed\n");
exit(EXIT_FAILURE);
}
caps = cap_from_text(captxt);
if (!caps) {
log_line("FATAL - set_cap: cap_from_text() failed\n");
exit(EXIT_FAILURE);
}
if (cap_set_proc(caps) == -1) {
log_line("FATAL - set_cap: cap_set_proc() failed\n");
exit(EXIT_FAILURE);
}
cap_free(caps);
}
void drop_root(uid_t uid, gid_t gid, char *captxt)
{
if (!captxt) {
log_line("FATAL - drop_root: captxt == NULL\n");
exit(EXIT_FAILURE);
}
if (uid == 0 || gid == 0) {
log_line("FATAL - drop_root: attempt to drop root to root?\n");
exit(EXIT_FAILURE);
}
set_cap(uid, gid, captxt);
if (setregid(gid, gid) == -1 || setreuid(uid, uid) == -1) {
log_line("FATAL - drop_root: failed to drop root!\n");
exit(EXIT_FAILURE);
}
}

36
linux.h Normal file
View File

@ -0,0 +1,36 @@
/* linux.h - ifchd Linux-specific functions include
* Time-stamp: <2004-06-13 njk>
*
* (C) 2004 Nicholas J. Kain <njk@aerifal.cx>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#ifndef NJK_IFCHD_LINUX_H_
#define NJK_IFCHD_LINUX_H_ 1
void clear_if_data(int idx);
void initialize_if_data(void);
void add_permitted_if(char *s);
int authorized_peer(int sk, pid_t pid, uid_t uid, gid_t gid);
void perform_interface(int idx, char *str);
void perform_ip(int idx, char *str);
void perform_subnet(int idx, char *str);
void perform_router(int idx, char *str);
void perform_mtu(int idx, char *str);
void perform_broadcast(int idx, char *str);
void drop_root(uid_t uid, gid_t gid, char *captxt);
#endif

46
log.c Normal file
View File

@ -0,0 +1,46 @@
/* log.c - simple logging support for ncron
(C) 2003 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <stdio.h>
#include <strings.h>
#include <syslog.h>
#include <stdarg.h>
#include "defines.h"
/* global logging flags */
int gflags_quiet = 0;
int gflags_detach = 1;
void log_line(char *format, ...) {
va_list argp;
if (format == NULL || gflags_quiet)
return;
if (gflags_detach) {
openlog("ifchd", LOG_PID, LOG_DAEMON);
va_start(argp, format);
vsyslog(LOG_ERR | LOG_DAEMON, format, argp);
va_end(argp);
closelog();
} else {
va_start(argp, format);
vfprintf(stderr, format, argp);
va_end(argp);
}
closelog();
}

26
log.h Normal file
View File

@ -0,0 +1,26 @@
/* log.h - simple logging support for ncron
(C) 2003 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef NJK_LOG_H_
#define NJK_LOG_H_ 1
extern int gflags_quiet;
extern int gflags_detach;
void log_line(char* format, ...);
#endif

13
ndhc/AUTHORS.udhcp Normal file
View File

@ -0,0 +1,13 @@
udhcp server/client package
-----------------------
Russ Dill <Russ.Dill@asu.edu>
Matthew Ramsay <matthewr@moreton.com.au>
Chris Trew <christ@moreton.com.au>
Other Credits:
--------------
Moreton Bay (http://www.moretonbay.com/)
Lineo (http://opensource.lineo.com)

339
ndhc/COPYING Normal file
View File

@ -0,0 +1,339 @@
GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.) You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get the
source code. And you must show them these terms so they know their
rights.
We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software. If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.
Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary. To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and
modification follow.
GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. The "Program", below,
refers to any such program or work, and a "work based on the Program"
means either the Program or any derivative work under copyright law:
that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another
language. (Hereinafter, translation is included without limitation in
the term "modification".) Each licensee is addressed as "you".
Activities other than copying, distribution and modification are not
covered by this License; they are outside its scope. The act of
running the Program is not restricted, and the output from the Program
is covered only if its contents constitute a work based on the
Program (independent of having been made by running the Program).
Whether that is true depends on what the Program does.
1. You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty;
and give any other recipients of the Program a copy of this License
along with the Program.
You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.
2. You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:
a) You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.
b) You must cause any work that you distribute or publish, that in
whole or in part contains or is derived from the Program or any
part thereof, to be licensed as a whole at no charge to all third
parties under the terms of this License.
c) If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display an
announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
these conditions, and telling the user how to view a copy of this
License. (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works. But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
exercise the right to control the distribution of derivative or
collective works based on the Program.
In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
the scope of this License.
3. You may copy and distribute the Program (or a work based on it,
under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:
a) Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections
1 and 2 above on a medium customarily used for software interchange; or,
b) Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; or,
c) Accompany it with the information you received as to the offer
to distribute corresponding source code. (This alternative is
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with such
an offer, in accord with Subsection b above.)
The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable. However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.
If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.
4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.
5. You are not required to accept this License, since you have not
signed it. However, nothing else grants you permission to modify or
distribute the Program or its derivative works. These actions are
prohibited by law if you do not accept this License. Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.
6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions. You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.
7. If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent issues),
conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License. If you cannot
distribute so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you
may not distribute the Program at all. For example, if a patent
license would not permit royalty-free redistribution of the Program by
all those who receive copies directly or indirectly through you, then
the only way you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.
If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.
It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices. Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.
This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the
original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License incorporates
the limitation as if written in the body of this License.
9. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time. Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.
Each version is given a distinguishing version number. If the Program
specifies a version number of this License which applies to it and "any
later version", you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation. If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.
10. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission. For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this. Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.
NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.
END OF TERMS AND CONDITIONS
Appendix: How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
convey the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) 19yy <name of author>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 19yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.
You should also get your employer (if you work as a programmer) or your
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library. If this is what you want to do, use the GNU Library General
Public License instead of this License.

43
ndhc/MODIFICATIONS Normal file
View File

@ -0,0 +1,43 @@
All modifications are to udhcp 0.9.8
All bugs should be blamed on Nicholas Kain, not the udhcp folks!
Great thanks go to the authors of udhcp (primarily Russ Dill), from which
ndhc is adapted.
CHANGES
-------
C99 compiler required
removed dhcp server support (use mainline udhcp)
removed sample scripts
added chroot support
added capability support
added setuid/setgid support
run_script now takes int argument (from enum)
script.c heavily modified to call ifchd
stripped command line option for custom script
bounds check all string functions
removed pidfile support: backgrounding model + chroot preclude it
manpage updated
removed busybox compat wrapper
convert all strncpy -> strlcpy
u_int*_t -> uint*_t (C99)
add_simple_option no longer does unspeakable things to the C language
character signedness issues fixed
casting bug [dhcpc.c:549 sizeof(signal) should be sizeof sig]
- won't bite except on an architecture where sizeof fnptr != sizeof int
LOG and DEBUG are abolished - functions are used instead, see log.c/log.h
C99 structure initializers used exclusively (C99)
Linux kernel headers no longer used under any circumstances.
- this is likely to break prehistoric systems running <glibc 2.1
exit() return codes now use EXIT_(SUCCESS|FAILURE) #defines and make more sense
close fd leak on failure in read_interface()
close fd leak on failure in kernel_packet()
char buffer[16] in perform_release() should not be static
don't bother to use a signal pipe - instead use static sig_atomic_t bools
convert lots of #defines to enums
break apart main client loop into maintainable functions
more discerning error handling
boundary check end_option()

69
ndhc/Makefile Normal file
View File

@ -0,0 +1,69 @@
# ndhc makefile
prefix=/usr
SBINDIR=/sbin
USRSBINDIR=${prefix}/sbin
USRBINDIR=${prefix}/bin
USRSHAREDIR=${prefix}/share
# Uncomment this for extra output and to compile with debugging symbols
#DEBUG=1
#CROSS_COMPILE=arm-uclibc-
CC = $(CROSS_COMPILE)gcc
LD = $(CROSS_COMPILE)gcc
INSTALL = install
VER := 0.9.8
OBJS_SHARED = nstrl.o log.o options.o socket.o packet.o rootcap.o
DHCPC_OBJS = dhcpc.o clientpacket.o script.o
EXEC2 = ndhc
OBJS2 = -lcap $(DHCPC_OBJS) $(OBJS_SHARED)
BOOT_PROGRAMS = ndhc
ifdef SYSLOG
CFLAGS += -DSYSLOG
endif
CFLAGS += -W -Wall -Wstrict-prototypes -DVERSION='"$(VER)"'
ifdef DEBUG
CFLAGS += -g -DDEBUG
STRIP=true
else
CFLAGS += -Os -fomit-frame-pointer
STRIP=$(CROSS_COMPILE)strip
endif
all: $(EXEC2)
$(STRIP) --remove-section=.note --remove-section=.comment $(EXEC2)
$(OBJS2) $(OBJS3): *.h Makefile
$(EXEC2): Makefile
.c.o:
$(CC) -c $(CFLAGS) $<
$(EXEC2): $(OBJS2)
$(LD) $(LDFLAGS) $(OBJS2) -o $(EXEC2)
tags:
-ctags -f tags *.[ch]
-cscope -b
install: all
$(INSTALL) $(BOOT_PROGRAMS) $(USRSBINDIR)
mkdir -p $(USRSHAREDIR)/man/man8
$(INSTALL) ndhc.8 ndhc.8 $(USRSHAREDIR)/man/man8
clean:
-rm -f ndhc *.o core
distclean:
-rm -f ndhc *.o tags cscope.out

54
ndhc/README Normal file
View File

@ -0,0 +1,54 @@
ndhc client
--------------------
The ndhc client negotiates a lease with the DHCP server and notifies
ifchd when a leases is obtained or lost.
command line options
-------------------
The command line options for the ndhc client are:
-c, --clientid=CLIENTID Client identifier
-H, --hostname=HOSTNAME Client hostname
-h, Alias for -H
-f, --foreground Do not fork after getting lease
-b, --background Fork to background if lease cannot be
immediately negotiated.
-i, --interface=INTERFACE Interface to use (default: eth0)
-n, --now Exit with failure if lease cannot be
immediately negotiated.
-q, --quit Quit after obtaining lease
-r, --request=IP IP address to request (default: none)
-v, --version Display version
If the requested IP address cannot be obtained, the client accepts the
address that the server offers.
note on ndhc's random seed
---------------------------
ndhc will seed its random number generator (used for generating xid's)
by reading /dev/urandom. If you have a lot of embedded systems on the same
network, with no entropy, you can either seed /dev/urandom by a method of
your own, or doing the following on startup:
ifconfig eth0 > /dev/urandom
in order to seed /dev/urandom with some data (mac address) unique to your
system. If reading /dev/urandom fails, ndhc will fall back to its old
behavior of seeding with time(0).
signals accepted by ndhc
-------------------------
ndhc also responds to SIGUSR1 and SIGUSR2. SIGUSR1 will force a renew state,
and SIGUSR2 will force a release of the current lease, and cause ndhc to
go into an inactive state (until it is killed, or receives a SIGUSR1). You do
not need to sleep between sending signals, as signals received are processed
sequencially in the order they are received.

7
ndhc/TODO Normal file
View File

@ -0,0 +1,7 @@
TODO
----
+ using time(0) breaks if the system clock changes, find a portable solution
+ make failure of reading functions revert to previous value, not the default
+ sanity code for option[OPT_LEN]
+ fix aliasing (ie: eth0:0)

256
ndhc/clientpacket.c Normal file
View File

@ -0,0 +1,256 @@
/* clientpacket.c
*
* Packet generation and dispatching functions for the DHCP client.
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <string.h>
#include <sys/socket.h>
#include <features.h>
#include <netpacket/packet.h>
#include <net/ethernet.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "dhcpd.h"
#include "packet.h"
#include "options.h"
#include "dhcpc.h"
#include "log.h"
/* Create a random xid */
unsigned long random_xid(void)
{
static int initialized;
if (!initialized) {
int fd;
unsigned long seed;
fd = open("/dev/urandom", O_RDONLY);
if (fd == -1 || read(fd, &seed, sizeof(seed)) < 0) {
log_line(LOG_WARNING, "Could not load seed from /dev/urandom: %s\n",
strerror(errno));
seed = time(0);
}
if (fd != -1)
close(fd);
srand(seed);
initialized++;
}
return rand();
}
/* initialize a packet with the proper defaults */
static void init_packet(struct dhcpMessage *packet, char type)
{
struct vendor {
char vendor;
char length;
char str[sizeof("ndhc "VERSION)];
} vendor_id = { DHCP_VENDOR, sizeof("ndhc "VERSION) - 1, "ndhc "VERSION};
init_header(packet, type);
memcpy(packet->chaddr, client_config.arp, 6);
add_option_string(packet->options, client_config.clientid);
if (client_config.hostname)
add_option_string(packet->options, client_config.hostname);
add_option_string(packet->options, (unsigned char *)&vendor_id);
}
/* Add a paramater request list for stubborn DHCP servers. Pull the data
* from the struct in options.c. Don't do bounds checking here because it
* goes towards the head of the packet. */
static void add_requests(struct dhcpMessage *packet)
{
int end = end_option(packet->options);
int i, len = 0;
packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
for (i = 0; options[i].code; i++)
if (options[i].flags & OPTION_REQ)
packet->options[end + OPT_DATA + len++] = options[i].code;
packet->options[end + OPT_LEN] = len;
packet->options[end + OPT_DATA + len] = DHCP_END;
}
/* Broadcast a DHCP discover packet to the network, with an optionally
* requested IP */
int send_discover(unsigned long xid, unsigned long requested)
{
struct dhcpMessage packet;
init_packet(&packet, DHCPDISCOVER);
packet.xid = xid;
if (requested)
add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
add_requests(&packet);
log_line(LOG_DEBUG, "Sending discover...\n");
return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
}
/* Broadcasts a DHCP request message */
int send_selecting(unsigned long xid, unsigned long server,
unsigned long requested)
{
struct dhcpMessage packet;
struct in_addr addr;
init_packet(&packet, DHCPREQUEST);
packet.xid = xid;
add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
add_simple_option(packet.options, DHCP_SERVER_ID, server);
add_requests(&packet);
addr.s_addr = requested;
log_line(LOG_DEBUG, "Sending select for %s...\n", inet_ntoa(addr));
return raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
}
/* Unicasts or broadcasts a DHCP renew message */
int send_renew(unsigned long xid, unsigned long server, unsigned long ciaddr)
{
struct dhcpMessage packet;
int ret = 0;
init_packet(&packet, DHCPREQUEST);
packet.xid = xid;
packet.ciaddr = ciaddr;
add_requests(&packet);
log_line(LOG_DEBUG, "Sending renew...\n");
if (server)
ret = kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
else
ret = raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
return ret;
}
/* Unicasts a DHCP release message */
int send_release(unsigned long server, unsigned long ciaddr)
{
struct dhcpMessage packet;
init_packet(&packet, DHCPRELEASE);
packet.xid = random_xid();
packet.ciaddr = ciaddr;
add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr);
add_simple_option(packet.options, DHCP_SERVER_ID, server);
log_line(LOG_DEBUG, "Sending release...\n");
return kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
}
/* return -1 on errors that are fatal for the socket,
* -2 for those that aren't */
int get_raw_packet(struct dhcpMessage *payload, int fd)
{
int bytes;
struct udp_dhcp_packet packet;
uint32_t source, dest;
uint16_t check;
memset(&packet, 0, sizeof(struct udp_dhcp_packet));
bytes = read(fd, &packet, sizeof(struct udp_dhcp_packet));
if (bytes < 0) {
debug(LOG_INFO, "couldn't read on raw listening socket -- ignoring\n");
usleep(500000); /* possible down interface, looping condition */
return -1;
}
if (bytes < (int) (sizeof(struct iphdr) + sizeof(struct udphdr))) {
debug(LOG_INFO, "message too short, ignoring\n");
return -2;
}
if (bytes < ntohs(packet.ip.tot_len)) {
debug(LOG_INFO, "Truncated packet\n");
return -2;
}
/* ignore any extra garbage bytes */
bytes = ntohs(packet.ip.tot_len);
/* Make sure its the right packet for us, and that it passes
* sanity checks */
if (packet.ip.protocol != IPPROTO_UDP
|| packet.ip.version != IPVERSION
|| packet.ip.ihl != sizeof(packet.ip) >> 2
|| packet.udp.dest != htons(CLIENT_PORT)
|| bytes > (int)sizeof(struct udp_dhcp_packet)
|| ntohs(packet.udp.len) != (short)(bytes - sizeof(packet.ip))) {
debug(LOG_INFO, "unrelated/bogus packet\n");
return -2;
}
/* check IP checksum */
check = packet.ip.check;
packet.ip.check = 0;
if (check != checksum(&(packet.ip), sizeof(packet.ip))) {
debug(LOG_INFO, "bad IP header checksum, ignoring\n");
return -1;
}
/* verify the UDP checksum by replacing the header with a psuedo header */
source = packet.ip.saddr;
dest = packet.ip.daddr;
check = packet.udp.check;
packet.udp.check = 0;
memset(&packet.ip, 0, sizeof(packet.ip));
packet.ip.protocol = IPPROTO_UDP;
packet.ip.saddr = source;
packet.ip.daddr = dest;
packet.ip.tot_len = packet.udp.len; /* cheat on the psuedo-header */
if (check && check != checksum(&packet, bytes)) {
debug(LOG_ERR, "packet with bad UDP checksum received, ignoring\n");
return -2;
}
memcpy(payload, &(packet.data),
bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
if (ntohl(payload->cookie) != DHCP_MAGIC) {
log_line(LOG_ERR, "received bogus message (bad magic) -- ignoring\n");
return -2;
}
debug(LOG_INFO, "oooooh!!! got some!\n");
return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
}

12
ndhc/clientpacket.h Normal file
View File

@ -0,0 +1,12 @@
#ifndef _CLIENTPACKET_H
#define _CLIENTPACKET_H
unsigned long random_xid(void);
int send_discover(unsigned long xid, unsigned long requested);
int send_selecting(unsigned long xid, unsigned long server, unsigned long requested);
int send_renew(unsigned long xid, unsigned long server, unsigned long ciaddr);
int send_renew(unsigned long xid, unsigned long server, unsigned long ciaddr);
int send_release(unsigned long server, unsigned long ciaddr);
int get_raw_packet(struct dhcpMessage *payload, int fd);
#endif

594
ndhc/dhcpc.c Normal file
View File

@ -0,0 +1,594 @@
/* dhcpc.c
*
* ndhc DHCP client
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
* Nicholas Kain <njk@-N0SPaM-.kain.us> 2004
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/file.h>
#include <unistd.h>
#include <getopt.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <time.h>
#include <string.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <errno.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <pwd.h>
#include <grp.h>
#include "dhcpd.h"
#include "dhcpc.h"
#include "options.h"
#include "clientpacket.h"
#include "packet.h"
#include "script.h"
#include "socket.h"
#include "log.h"
#include "rootcap.h"
#include "nstrl.h"
static unsigned long requested_ip, server_addr, timeout;
static unsigned long lease, t1, t2, xid, start;
static int state, packet_num, fd, listen_mode;
static sig_atomic_t pending_exit, pending_renew, pending_release;
enum {
LISTEN_NONE,
LISTEN_KERNEL,
LISTEN_RAW
};
struct client_config_t client_config = {
/* Default options. */
.abort_if_no_lease = 0,
.foreground = 0,
.quit_after_lease = 0,
.background_if_no_lease = 0,
.interface = "eth0",
.script = "none",
.clientid = NULL,
.hostname = NULL,
.ifindex = 0,
.arp = "\0",
};
static void show_usage(void)
{
printf(
"Usage: ndhc [OPTIONS]\n\n"
" -c, --clientid=CLIENTID Client identifier\n"
" -H, --hostname=HOSTNAME Client hostname\n"
" -h Alias for -H\n"
" -f, --foreground Do not fork after getting lease\n"
" -b, --background Fork to background if lease cannot be\n"
" immediately negotiated.\n"
" -i, --interface=INTERFACE Interface to use (default: eth0)\n"
" -n, --now Exit with failure if lease cannot be\n"
" immediately negotiated.\n"
" -q, --quit Quit after obtaining lease\n"
" -r, --request=IP IP address to request (default: none)\n"
" -u, --user Change privileges to this user\n"
" -C, --chroot Directory to which udhcp should chroot\n"
" -v, --version Display version\n"
);
exit(EXIT_SUCCESS);
}
/* just a little helper */
static void change_mode(int new_mode)
{
debug(LOG_INFO, "entering %s listen mode",
new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
close(fd);
fd = -1;
listen_mode = new_mode;
}
/* perform a renew */
static void perform_renew(void)
{
log_line(LOG_INFO, "Performing a DHCP renew...\n");
switch (state) {
case BOUND:
change_mode(LISTEN_KERNEL);
case RENEWING:
case REBINDING:
state = RENEW_REQUESTED;
break;
case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
run_script(NULL, SCRIPT_DECONFIG);
case REQUESTING:
case RELEASED:
change_mode(LISTEN_RAW);
state = INIT_SELECTING;
break;
case INIT_SELECTING:
break;
}
/* start things over */
packet_num = 0;
/* Kill any timeouts because the user wants this to hurry along */
timeout = 0;
}
/* perform a release */
static void perform_release(void)
{
char buf[16];
struct in_addr temp_addr;
buf[16] = '\0';
/* send release packet */
if (state == BOUND || state == RENEWING || state == REBINDING) {
temp_addr.s_addr = server_addr;
snprintf(buf, sizeof buf, "%s", inet_ntoa(temp_addr));
temp_addr.s_addr = requested_ip;
log_line(LOG_INFO, "Unicasting a release of %s to %s.\n",
inet_ntoa(temp_addr), buf);
send_release(server_addr, requested_ip); /* unicast */
run_script(NULL, SCRIPT_DECONFIG);
}
log_line(LOG_INFO, "Entering released state.\n");
change_mode(LISTEN_NONE);
state = RELEASED;
timeout = 0x7fffffff;
}
static void signal_handler(int sig)
{
switch (sig) {
case SIGUSR1:
pending_renew = 1;
break;
case SIGUSR2:
pending_release = 1;
break;
case SIGTERM:
pending_exit = 1;
break;
}
}
static void background(void)
{
if (daemon(0, 0) == -1) {
perror("fork");
exit(EXIT_SUCCESS);
}
client_config.foreground = 1; /* Do not fork again. */
}
static void handle_timeout(void)
{
time_t now = time(0);
/* timeout dropped to zero */
switch (state) {
case INIT_SELECTING:
if (packet_num < 3) {
if (packet_num == 0)
xid = random_xid();
/* send discover packet */
send_discover(xid, requested_ip); /* broadcast */
timeout = now + ((packet_num == 2) ? 4 : 2);
packet_num++;
} else {
if (client_config.background_if_no_lease) {
log_line(LOG_INFO, "No lease, going to background.\n");
background();
} else if (client_config.abort_if_no_lease) {
log_line(LOG_INFO, "No lease, failing.\n");
exit(EXIT_FAILURE);
}
/* wait to try again */
packet_num = 0;
timeout = now + 60;
}
break;
case RENEW_REQUESTED:
case REQUESTING:
if (packet_num < 3) {
/* send request packet */
if (state == RENEW_REQUESTED)
/* unicast */
send_renew(xid, server_addr, requested_ip);
else
/* broadcast */
send_selecting(xid, server_addr, requested_ip);
timeout = now + ((packet_num == 2) ? 10 : 2);
packet_num++;
} else {
/* timed out, go back to init state */
if (state == RENEW_REQUESTED)
run_script(NULL, SCRIPT_DECONFIG);
state = INIT_SELECTING;
timeout = now;
packet_num = 0;
change_mode(LISTEN_RAW);
}
break;
case BOUND:
/* Lease is starting to run out, time to enter renewing state */
state = RENEWING;
change_mode(LISTEN_KERNEL);
debug(LOG_INFO, "Entering renew state.\n");
/* fall right through */
case RENEWING:
/* Either set a new T1, or enter REBINDING state */
if ((t2 - t1) <= (lease / 14400 + 1)) {
/* timed out, enter rebinding state */
state = REBINDING;
timeout = now + (t2 - t1);
debug(LOG_INFO, "Entering rebinding state.\n");
} else {
/* send a request packet */
send_renew(xid, server_addr, requested_ip); /* unicast */
t1 = ((t2 - t1) >> 1) + t1;
timeout = t1 + start;
}
break;
case REBINDING:
/* Either set a new T2, or enter INIT state */
if ((lease - t2) <= (lease / 14400 + 1)) {
/* timed out, enter init state */
state = INIT_SELECTING;
log_line(LOG_INFO, "Lease lost, entering init state.\n");
run_script(NULL, SCRIPT_DECONFIG);
timeout = now;
packet_num = 0;
change_mode(LISTEN_RAW);
} else {
/* send a request packet */
send_renew(xid, 0, requested_ip); /* broadcast */
t2 = ((lease - t2) >> 1) + t2;
timeout = t2 + start;
}
break;
case RELEASED:
/* yah, I know, *you* say it would never happen */
timeout = 0x7fffffff;
break;
}
}
static void handle_packet(void)
{
unsigned char *temp = NULL, *message = NULL;
int len;
time_t now = time(0);
struct in_addr temp_addr;
struct dhcpMessage packet;
debug(LOG_INFO, "got a packet\n");
if (listen_mode == LISTEN_KERNEL)
len = get_packet(&packet, fd);
else
len = get_raw_packet(&packet, fd);
if (len == -1 && errno != EINTR) {
debug(LOG_INFO, "error on read, %s, reopening socket.\n",
strerror(errno));
change_mode(listen_mode); /* just close and reopen */
}
if (len < 0)
return;
if (packet.xid != xid) {
debug(LOG_INFO, "Ignoring XID %lx (our xid is %lx).\n",
(unsigned long) packet.xid, xid);
return;
}
if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
debug(LOG_ERR, "couldnt get option from packet -- ignoring\n");
return;
}
switch (state) {
case INIT_SELECTING:
/* Must be a DHCPOFFER to one of our xid's */
if (*message == DHCPOFFER) {
if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
memcpy(&server_addr, temp, 4);
xid = packet.xid;
requested_ip = packet.yiaddr;
/* enter requesting state */
state = REQUESTING;
timeout = now;
packet_num = 0;
} else {
debug(LOG_ERR, "No server ID in message\n");
}
}
break;
case RENEW_REQUESTED:
case REQUESTING:
case RENEWING:
case REBINDING:
if (*message == DHCPACK) {
if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
log_line(LOG_ERR,
"No lease time received, assuming 1h.\n");
lease = 60 * 60;
} else {
memcpy(&lease, temp, 4);
lease = ntohl(lease);
}
/* enter bound state */
t1 = lease >> 1;
/* little fixed point for n * .875 */
t2 = (lease * 0x7) >> 3;
temp_addr.s_addr = packet.yiaddr;
log_line(LOG_INFO,
"Lease of %s obtained, lease time %ld.\n",
inet_ntoa(temp_addr), lease);
start = now;
timeout = t1 + start;
requested_ip = packet.yiaddr;
run_script(&packet,
((state == RENEWING || state == REBINDING)
? SCRIPT_RENEW : SCRIPT_BOUND));
state = BOUND;
change_mode(LISTEN_NONE);
if (client_config.quit_after_lease)
exit(EXIT_SUCCESS);
if (!client_config.foreground)
background();
} else if (*message == DHCPNAK) {
/* return to init state */
log_line(LOG_INFO, "Received DHCP NAK.\n");
run_script(&packet, SCRIPT_NAK);
if (state != REQUESTING)
run_script(NULL, SCRIPT_DECONFIG);
state = INIT_SELECTING;
timeout = now;
requested_ip = 0;
packet_num = 0;
change_mode(LISTEN_RAW);
sleep(3); /* avoid excessive network traffic */
}
break;
case BOUND:
case RELEASED:
default:
break;
}
}
static int do_work(void)
{
struct timeval tv;
fd_set rfds;
for (;;) {
/* Handle signals asynchronously. */
if (pending_renew)
perform_renew();
if (pending_release)
perform_release();
if (pending_exit) {
log_line(LOG_INFO, "Received SIGTERM. Exiting gracefully.\n");
exit(EXIT_SUCCESS);
}
tv.tv_sec = timeout - time(0);
tv.tv_usec = 0;
if (listen_mode != LISTEN_NONE && fd < 0) {
if (listen_mode == LISTEN_KERNEL)
fd = listen_socket(INADDR_ANY, CLIENT_PORT,
client_config.interface);
else
fd = raw_socket(client_config.ifindex);
if (fd < 0) {
log_line(LOG_ERR, "FATAL: couldn't listen on socket: %s.\n",
strerror(errno));
exit(EXIT_FAILURE);
}
}
if (tv.tv_sec <= 0) {
handle_timeout();
continue;
}
FD_ZERO(&rfds);
if (fd >= 0)
FD_SET(fd, &rfds);
debug(LOG_INFO, "Waiting on select...\n");
if (select(fd + 1, &rfds, NULL, NULL, &tv) == -1) {
switch (errno) {
case EBADF:
fd = -1;
default:
debug(LOG_ERR, "Error: \"%s\" on select!\n",
strerror(errno));
case EINTR: /* Signal received, go back to top. */
continue;
}
}
debug(LOG_INFO, "select suceeded\n");
if (listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds))
handle_packet();
}
}
int main(int argc, char **argv)
{
char *chroot_dir = NULL;
int c, len;
struct passwd *pwd;
uid_t uid = 0;
gid_t gid = 0;
static struct option arg_options[] = {
{"clientid", required_argument, 0, 'c'},
{"foreground", no_argument, 0, 'f'},
{"background", no_argument, 0, 'b'},
{"hostname", required_argument, 0, 'H'},
{"hostname", required_argument, 0, 'h'},
{"interface", required_argument, 0, 'i'},
{"now", no_argument, 0, 'n'},
{"quit", no_argument, 0, 'q'},
{"request", required_argument, 0, 'r'},
{"version", no_argument, 0, 'v'},
{"user", required_argument, 0, 'u'},
{"chroot", required_argument, 0, 'C'},
{"help", no_argument, 0, '?'},
{0, 0, 0, 0}
};
/* get options */
while (1) {
int option_index = 0;
c = getopt_long(argc, argv, "c:fbH:h:i:np:qr:u:C:v", arg_options,
&option_index);
if (c == -1) break;
switch (c) {
case 'c':
len = strlen(optarg) > 255 ? 255 : strlen(optarg);
if (client_config.clientid)
free(client_config.clientid);
client_config.clientid = malloc(len + 2);
client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
client_config.clientid[OPT_LEN] = len;
client_config.clientid[OPT_DATA] = '\0';
strlcpy((char *)client_config.clientid + OPT_DATA, optarg, len);
break;
case 'f':
client_config.foreground = 1;
break;
case 'b':
client_config.background_if_no_lease = 1;
break;
case 'h':
case 'H':
len = strlen(optarg) > 255 ? 255 : strlen(optarg);
if (client_config.hostname)
free(client_config.hostname);
client_config.hostname = malloc(len + 2);
client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
client_config.hostname[OPT_LEN] = len;
strlcpy((char*)client_config.hostname + 2, optarg, len);
break;
case 'i':
client_config.interface = optarg;
break;
case 'n':
client_config.abort_if_no_lease = 1;
break;
case 'q':
client_config.quit_after_lease = 1;
break;
case 'r':
requested_ip = inet_addr(optarg);
break;
case 'u':
pwd = getpwnam(optarg);
if (pwd) {
uid = (int)pwd->pw_uid;
gid = (int)pwd->pw_gid;
} else {
printf("Bad username provided.\n");
exit(EXIT_FAILURE);
}
break;
case 'C':
len = strlen(optarg) > 255 ? 255 : strlen(optarg);
chroot_dir = malloc(len + 2);
memset(chroot_dir, '\0', len + 2);
strlcpy(chroot_dir, optarg, len);
break;
case 'v':
printf("ndhc, version %s\n\n", VERSION);
exit(EXIT_SUCCESS);
break;
default:
show_usage();
}
}
log_line(LOG_INFO, "ndhc client (v%s) started.\n", VERSION);
if (read_interface(client_config.interface, &client_config.ifindex,
NULL, client_config.arp) < 0)
exit(EXIT_FAILURE);
if (!client_config.clientid) {
client_config.clientid = malloc(6 + 3);
client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
client_config.clientid[OPT_LEN] = 7;
client_config.clientid[OPT_DATA] = 1;
memcpy(client_config.clientid + 3, client_config.arp, 6);
}
/* setup signal handlers */
signal(SIGUSR1, signal_handler);
signal(SIGUSR2, signal_handler);
signal(SIGTERM, signal_handler);
if (chdir(chroot_dir)) {
printf("Failed to chdir(%s)!\n", chroot_dir);
exit(EXIT_FAILURE);
}
if (chroot(chroot_dir)) {
printf("Failed to chroot(%s)!\n", chroot_dir);
exit(EXIT_FAILURE);
}
drop_root(uid, gid,
"cap_net_bind_service,cap_net_broadcast,cap_net_raw=ep");
state = INIT_SELECTING;
run_script(NULL, SCRIPT_DECONFIG);
change_mode(LISTEN_RAW);
do_work();
return EXIT_SUCCESS;
}

31
ndhc/dhcpc.h Normal file
View File

@ -0,0 +1,31 @@
#ifndef _DHCPC_H
#define _DHCPC_H
enum {
INIT_SELECTING,
REQUESTING,
BOUND,
RENEWING,
REBINDING,
INIT_REBOOT,
RENEW_REQUESTED,
RELEASED
};
struct client_config_t {
char foreground; /* Do not fork */
char quit_after_lease; /* Quit after obtaining lease */
char abort_if_no_lease; /* Abort if no lease */
char background_if_no_lease; /* Fork to background if no lease */
char *interface; /* The name of the interface to use */
char *script; /* User script to run at dhcp events */
unsigned char *clientid; /* Optional client id to use */
unsigned char *hostname; /* Optional hostname to use */
int ifindex; /* Index number of the interface to use */
unsigned char arp[6]; /* Our arp address */
};
extern struct client_config_t client_config;
#endif

132
ndhc/dhcpd.h Normal file
View File

@ -0,0 +1,132 @@
/* dhcpd.h */
#ifndef _DHCPD_H
#define _DHCPD_H
#include <netinet/ip.h>
#include <netinet/udp.h>
#include "leases.h"
/************************************/
/* Defaults _you_ may want to tweak */
/************************************/
/* the period of time the client is allowed to use that address */
#define LEASE_TIME (60*60*24*10) /* 10 days of seconds */
/*****************************************************************/
/* Do not modify below here unless you know what you are doing!! */
/*****************************************************************/
/* DHCP protocol -- see RFC 2131 */
#define SERVER_PORT 67
#define CLIENT_PORT 68
#define DHCP_MAGIC 0x63825363
/* DHCP option codes (partial list) */
#define DHCP_PADDING 0x00
#define DHCP_SUBNET 0x01
#define DHCP_TIME_OFFSET 0x02
#define DHCP_ROUTER 0x03
#define DHCP_TIME_SERVER 0x04
#define DHCP_NAME_SERVER 0x05
#define DHCP_DNS_SERVER 0x06
#define DHCP_LOG_SERVER 0x07
#define DHCP_COOKIE_SERVER 0x08
#define DHCP_LPR_SERVER 0x09
#define DHCP_HOST_NAME 0x0c
#define DHCP_BOOT_SIZE 0x0d
#define DHCP_DOMAIN_NAME 0x0f
#define DHCP_SWAP_SERVER 0x10
#define DHCP_ROOT_PATH 0x11
#define DHCP_IP_TTL 0x17
#define DHCP_MTU 0x1a
#define DHCP_BROADCAST 0x1c
#define DHCP_NTP_SERVER 0x2a
#define DHCP_WINS_SERVER 0x2c
#define DHCP_REQUESTED_IP 0x32
#define DHCP_LEASE_TIME 0x33
#define DHCP_OPTION_OVER 0x34
#define DHCP_MESSAGE_TYPE 0x35
#define DHCP_SERVER_ID 0x36
#define DHCP_PARAM_REQ 0x37
#define DHCP_MESSAGE 0x38
#define DHCP_MAX_SIZE 0x39
#define DHCP_T1 0x3a
#define DHCP_T2 0x3b
#define DHCP_VENDOR 0x3c
#define DHCP_CLIENT_ID 0x3d
#define DHCP_END 0xFF
enum {
BOOTREQUEST = 1,
BOOTREPLY = 2
};
#define ETH_10MB 1
#define ETH_10MB_LEN 6
enum {
DHCPDISCOVER = 1,
DHCPOFFER = 2,
DHCPREQUEST = 3,
DHCPDECLINE = 4,
DHCPACK = 5,
DHCPNAK = 6,
DHCPRELEASE = 7,
DHCPINFORM = 8
};
#define BROADCAST_FLAG 0x8000
enum {
OPTION_FIELD = 0,
FILE_FIELD = 1,
SNAME_FIELD = 2
};
#define MAC_BCAST_ADDR (unsigned char *) "\xff\xff\xff\xff\xff\xff"
enum {
OPT_CODE = 0,
OPT_LEN = 1,
OPT_DATA = 2
};
struct option_set {
unsigned char *data;
struct option_set *next;
};
struct server_config_t {
uint32_t server; /* Our IP, in network order */
uint32_t start; /* Start address of leases, network order */
uint32_t end; /* End of leases, network order */
struct option_set *options; /* List of DHCP options loaded from the config file */
char *interface; /* The name of the interface to use */
int ifindex; /* Index number of the interface to use */
unsigned char arp[6]; /* Our arp address */
unsigned long lease; /* lease time in seconds (host order) */
unsigned long max_leases; /* maximum number of leases (including reserved address) */
char remaining; /* should the lease file be interpreted as lease time remaining, or
* as the time the lease expires */
unsigned long auto_time; /* how long should udhcpd wait before writing a config file.
* if this is zero, it will only write one on SIGUSR1 */
unsigned long decline_time; /* how long an address is reserved if a client returns a
* decline message */
unsigned long conflict_time; /* how long an arp conflict offender is leased for */
unsigned long offer_time; /* how long an offered address is reserved */
unsigned long min_lease; /* minimum lease a client can request*/
char *lease_file;
char *notify_file; /* What to run whenever leases are written */
uint32_t siaddr; /* next server bootp option */
char *sname; /* bootp server name */
char *boot_file; /* bootp boot file option */
};
extern struct server_config_t server_config;
extern struct dhcpOfferedAddr *leases;
#endif

24
ndhc/leases.h Normal file
View File

@ -0,0 +1,24 @@
/* leases.h */
#ifndef _LEASES_H
#define _LEASES_H
struct dhcpOfferedAddr {
uint8_t chaddr[16];
uint32_t yiaddr; /* network order */
uint32_t expires; /* host order */
};
extern unsigned char blank_chaddr[];
void clear_lease(uint8_t *chaddr, uint32_t yiaddr);
struct dhcpOfferedAddr *add_lease(uint8_t *chaddr, uint32_t yiaddr, unsigned long lease);
int lease_expired(struct dhcpOfferedAddr *lease);
struct dhcpOfferedAddr *oldest_expired_lease(void);
struct dhcpOfferedAddr *find_lease_by_chaddr(uint8_t *chaddr);
struct dhcpOfferedAddr *find_lease_by_yiaddr(uint32_t yiaddr);
uint32_t find_address(int check_expired);
int check_ip(uint32_t addr);
#endif

20
ndhc/log.c Normal file
View File

@ -0,0 +1,20 @@
#include <stdio.h>
#include <strings.h>
#include <stdarg.h>
#include <syslog.h>
void log_line(int level, char *format, ...) {
va_list argp;
if (format == NULL) return;
va_start(argp, format);
vfprintf(stderr, format, argp);
va_end(argp);
openlog("ndhc", 0, 0);
va_start(argp, format);
vsyslog(level, format, argp);
va_end(argp);
closelog();
}

11
ndhc/log.h Normal file
View File

@ -0,0 +1,11 @@
#ifndef H_LOG_H__
#define H_LOG_H__
#include <syslog.h>
void log_line(int level, char *format, ...);
#ifdef DEBUG
#define debug log_line
#else
#define debug(...)
#endif
#endif

56
ndhc/ndhc.8 Normal file
View File

@ -0,0 +1,56 @@
.TH NDHC 8 2004-02-25 Linux "Linux Administrator's Manual"
.SH NAME
ndhc \- secure DHCP client
.SH SYNOPSIS
.B ndhc
.RI [ OPTION ]...
.SH DESCRIPTION
The ndhc client negotiates a lease with the DHCP server and
informs ifchd of the change when it is obtained or lost.
.SH OPTIONS
.TP
.BI \-c\ CLIENTID ,\ \-\-clientid= CLIENTID
Send the client identifier
.IR CLIENTID .
.TP
.BR -f ,\ \-\-foreground
Do not fork after obtaining a lease.
.TP
.BI \-H\ HOSTNAME ,\ \-\-hostname= HOSTNAME
Send the client hostname
.IR HOSTNAME .
.TP
.BI \-h\ HOSTNAME
Alias for -H
.IR HOSTNAME .
.TP
.BI \-i\ INTERFACE ,\ \-\-interface= INTERFACE
Configure
.IR INTERFACE .
.TP
.BR -n ,\ \-\-now
Exit with failure if a lease cannot be obtained.
.TP
.BR -q ,\ \-\-quit
Exit after obtaining a lease.
.TP
.BI \-r\ ADDRESS ,\ \-\-request= ADDRESS
Request IP address
.IR ADDRESS .
.TP
.BR -v ,\ \-\-version
Display version.
.SH NOTES
.B ndhc
responds to the following signals:
.TP
.B SIGUSR1
This signal causes
.B ndhc
to renew the current lease or, if it does not have one, obtain a
new lease.
.TP
.B SIGUSR2
This signal caused
.B ndhc
to release the current lease.

48
ndhc/nstrl.c Normal file
View File

@ -0,0 +1,48 @@
/* nstrl.c - strlcpy/strlcat implementation
Time-stamp: <2003-05-28 02:35:13 njk>
(C) 2003 Nicholas Jay Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <unistd.h>
#ifndef HAVE_STRLCPY
size_t strlcpy (char *dest, char *src, size_t size)
{
register char *d = dest, *s = src;
for (; *s != '\0' && size > 0; size--, d++, s++)
*d = *s;
*d = '\0';
return (d - dest) + (s - src);
}
size_t strlcat (char *dest, char *src, size_t size)
{
register char *d = dest, *s = src;
for (; size > 0 && *d != '\0'; size--, d++);
for (; *s != '\0' && size > 0; size--, d++, s++)
*d = *s;
*d = '\0';
return (d - dest) + (s - src);
}
#endif

25
ndhc/nstrl.h Normal file
View File

@ -0,0 +1,25 @@
/* nstrl.h - header file for strlcpy/strlcat implementation
Time-stamp: <2003-05-28 02:34:47 njk>
(C) 2003 Nicholas Jay Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef NJK_HAVE_STRL_
size_t strlcpy (char *dest, char *src, size_t size);
size_t strlcat (char *dest, char *src, size_t size);
#endif
#define NJK_HAVE_STRL_ 1

228
ndhc/options.c Normal file
View File

@ -0,0 +1,228 @@
/*
* options.c -- DHCP server option packet tools
* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
* Fixes and hardening: Nicholas Kain <njk@-n0xZpam-.kain.us>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "log.h"
#include "dhcpd.h"
#include "options.h"
#include "leases.h"
/* supported options are easily added here */
struct dhcp_option options[] = {
/* name[10] flags code */
{"subnet", OPTION_IP | OPTION_REQ, 0x01},
{"timezone", OPTION_S32, 0x02},
{"router", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03},
{"timesvr", OPTION_IP | OPTION_LIST, 0x04},
{"namesvr", OPTION_IP | OPTION_LIST, 0x05},
{"dns", OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06},
{"logsvr", OPTION_IP | OPTION_LIST, 0x07},
{"cookiesvr", OPTION_IP | OPTION_LIST, 0x08},
{"lprsvr", OPTION_IP | OPTION_LIST, 0x09},
{"hostname", OPTION_STRING | OPTION_REQ, 0x0c},
{"bootsize", OPTION_U16, 0x0d},
{"domain", OPTION_STRING | OPTION_REQ, 0x0f},
{"swapsvr", OPTION_IP, 0x10},
{"rootpath", OPTION_STRING, 0x11},
{"ipttl", OPTION_U8, 0x17},
{"mtu", OPTION_U16, 0x1a},
{"broadcast", OPTION_IP | OPTION_REQ, 0x1c},
{"ntpsrv", OPTION_IP | OPTION_LIST, 0x2a},
{"wins", OPTION_IP | OPTION_LIST, 0x2c},
{"requestip", OPTION_IP, 0x32},
{"lease", OPTION_U32, 0x33},
{"dhcptype", OPTION_U8, 0x35},
{"serverid", OPTION_IP, 0x36},
{"message", OPTION_STRING, 0x38},
{"tftp", OPTION_STRING, 0x42},
{"bootfile", OPTION_STRING, 0x43},
{"", 0x00, 0x00}
};
/* Lengths of the different option types */
int option_lengths[] = {
[OPTION_IP] = 4,
[OPTION_IP_PAIR] = 8,
[OPTION_BOOLEAN] = 1,
[OPTION_STRING] = 1,
[OPTION_U8] = 1,
[OPTION_U16] = 2,
[OPTION_S16] = 2,
[OPTION_U32] = 4,
[OPTION_S32] = 4
};
/* get an option with bounds checking (warning, not aligned). */
unsigned char *get_option(struct dhcpMessage *packet, int code)
{
int i = 0, length = 308;
unsigned char *optionptr;
int over = 0, done = 0, curr = OPTION_FIELD;
optionptr = packet->options;
while (!done) {
if (i >= length) {
log_line(LOG_WARNING, "bogus packet, option fields too long.\n");
return NULL;
}
if (optionptr[i + OPT_CODE] == code) {
if (i + 1 + optionptr[i + OPT_LEN] >= length) {
log_line(LOG_WARNING, "bogus packet, option fields too long.\n");
return NULL;
}
return optionptr + i + 2;
}
switch (optionptr[i + OPT_CODE]) {
case DHCP_PADDING:
i++;
break;
case DHCP_OPTION_OVER:
if (i + 1 + optionptr[i + OPT_LEN] >= length) {
log_line(LOG_WARNING,
"bogus packet, option fields too long.\n");
return NULL;
}
over = optionptr[i + 3];
i += optionptr[OPT_LEN] + 2;
break;
case DHCP_END:
if (curr == OPTION_FIELD && over & FILE_FIELD) {
optionptr = packet->file;
i = 0;
length = 128;
curr = FILE_FIELD;
} else if (curr == FILE_FIELD && over & SNAME_FIELD) {
optionptr = packet->sname;
i = 0;
length = 64;
curr = SNAME_FIELD;
} else done = 1;
break;
default:
i += optionptr[OPT_LEN + i] + 2;
}
}
return NULL;
}
/* return the position of the 'end' option */
int end_option(unsigned char *optionptr)
{
int i = 0;
while (i < 308 && optionptr[i] != DHCP_END) {
if (optionptr[i] == DHCP_PADDING)
++i;
else
i += optionptr[i + OPT_LEN] + 2;
}
return (i < 308 ? i : 308);
}
/* add an option string to the options (an option string contains an option
* code, length, then data) */
int add_option_string(unsigned char *optionptr, unsigned char *string)
{
int end = end_option(optionptr);
/* end position + string length + option code/length + end option */
if (end + string[OPT_LEN] + 2 + 1 >= 308) {
log_line(LOG_ERR, "Option 0x%02x did not fit into the packet!\n",
string[OPT_CODE]);
return 0;
}
debug(LOG_INFO, "adding option 0x%02x\n", string[OPT_CODE]);
memcpy(optionptr + end, string, string[OPT_LEN] + 2);
optionptr[end + string[OPT_LEN] + 2] = DHCP_END;
return string[OPT_LEN] + 2;
}
int add_simple_option(unsigned char *optionptr, unsigned char code,
uint32_t data)
{
int i, length = 0;
unsigned char option[2 + 4];
for (i = 0; options[i].code; i++)
if (options[i].code == code) {
length = option_lengths[options[i].flags & TYPE_MASK];
}
option[OPT_CODE] = code;
option[OPT_LEN] = (unsigned char)length;
if (!length) {
debug(LOG_ERR, "Could not add option 0x%02x\n", code);
return 0;
} else if (length == 1) {
uint8_t t = (uint8_t)data;
memcpy(option + 2, &t, 1);
} else if (length == 2) {
uint16_t t = (uint16_t)data;
memcpy(option + 2, &t, 2);
} else if (length == 4) {
uint32_t t = (uint32_t)data;
memcpy(option + 2, &t, 4);
}
return add_option_string(optionptr, option);
}
/* find option 'code' in opt_list */
struct option_set *find_option(struct option_set *opt_list, char code)
{
while (opt_list && opt_list->data[OPT_CODE] < code)
opt_list = opt_list->next;
if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
else return NULL;
}
/* add an option to the opt_list */
void attach_option(struct option_set **opt_list, struct dhcp_option *option,
char *buffer, int length)
{
struct option_set *existing, *new, **curr;
/* add it to an existing option */
if ((existing = find_option(*opt_list, option->code))) {
debug(LOG_INFO, "Attaching option %s to existing member of list\n",
option->name);
if (option->flags & OPTION_LIST) {
if (existing->data[OPT_LEN] + length <= 255) {
existing->data = realloc(existing->data,
existing->data[OPT_LEN] + length + 2);
memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer,
length);
existing->data[OPT_LEN] += length;
} /* else, ignore the data; we could put this in a second option
in the future */
} /* else, ignore the new data */
} else {
debug(LOG_INFO, "Attaching option %s to list\n", option->name);
/* make a new option */
new = malloc(sizeof(struct option_set));
new->data = malloc(length + 2);
new->data[OPT_CODE] = option->code;
new->data[OPT_LEN] = length;
memcpy(new->data + 2, buffer, length);
curr = opt_list;
while (*curr && (*curr)->data[OPT_CODE] < option->code)
curr = &(*curr)->next;
new->next = *curr;
*curr = new;
}
}

40
ndhc/options.h Normal file
View File

@ -0,0 +1,40 @@
/* options.h */
#ifndef _OPTIONS_H
#define _OPTIONS_H
#include "packet.h"
#define TYPE_MASK 0x0F
enum {
OPTION_IP=1,
OPTION_IP_PAIR,
OPTION_STRING,
OPTION_BOOLEAN,
OPTION_U8,
OPTION_U16,
OPTION_S16,
OPTION_U32,
OPTION_S32
};
#define OPTION_REQ 0x10 /* have the client request this option */
#define OPTION_LIST 0x20 /* There can be a list of 1 or more of these */
struct dhcp_option {
char name[10];
char flags;
unsigned char code;
};
extern struct dhcp_option options[];
extern int option_lengths[];
unsigned char *get_option(struct dhcpMessage *packet, int code);
int end_option(unsigned char *optionptr);
int add_option_string(unsigned char *optionptr, unsigned char *string);
int add_simple_option(unsigned char *optionptr, unsigned char code, uint32_t data);
struct option_set *find_option(struct option_set *opt_list, char code);
void attach_option(struct option_set **opt_list, struct dhcp_option *option, char *buffer, int length);
#endif

203
ndhc/packet.c Normal file
View File

@ -0,0 +1,203 @@
#include <unistd.h>
#include <string.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <features.h>
#include <netpacket/packet.h>
#include <net/ethernet.h>
#include <errno.h>
#include "packet.h"
#include "log.h"
#include "dhcpd.h"
#include "options.h"
void init_header(struct dhcpMessage *packet, char type)
{
memset(packet, 0, sizeof(struct dhcpMessage));
switch (type) {
case DHCPDISCOVER:
case DHCPREQUEST:
case DHCPRELEASE:
case DHCPINFORM:
packet->op = BOOTREQUEST;
break;
case DHCPOFFER:
case DHCPACK:
case DHCPNAK:
packet->op = BOOTREPLY;
}
packet->htype = ETH_10MB;
packet->hlen = ETH_10MB_LEN;
packet->cookie = htonl(DHCP_MAGIC);
packet->options[0] = DHCP_END;
add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
}
/* read a packet from socket fd, return -1 on read error, -2 on packet error */
int get_packet(struct dhcpMessage *packet, int fd)
{
int bytes;
int i;
const char broken_vendors[][8] = {
"MSFT 98",
""
};
unsigned char *vendor;
memset(packet, 0, sizeof(struct dhcpMessage));
bytes = read(fd, packet, sizeof(struct dhcpMessage));
if (bytes < 0) {
debug(LOG_INFO, "couldn't read on listening socket, ignoring\n");
return -1;
}
if (ntohl(packet->cookie) != DHCP_MAGIC) {
log_line(LOG_ERR, "received bogus message, ignoring.\n");
return -2;
}
debug(LOG_INFO, "Received a packet\n");
if (packet->op == BOOTREQUEST
&& (vendor = get_option(packet, DHCP_VENDOR)))
{
for (i = 0; broken_vendors[i][0]; i++) {
if (vendor[OPT_LEN - 2] == (unsigned char)strlen(broken_vendors[i])
&& !strncmp((char *)vendor, broken_vendors[i],
vendor[OPT_LEN - 2]))
{
debug(LOG_INFO, "broken client (%s), forcing broadcast\n",
broken_vendors[i]);
packet->flags |= htons(BROADCAST_FLAG);
}
}
}
return bytes;
}
uint16_t checksum(void *addr, int count)
{
/* Compute Internet Checksum for "count" bytes
* beginning at location "addr".
*/
register int32_t sum = 0;
uint16_t *source = (uint16_t *)addr;
while (count > 1) {
sum += *source++;
count -= 2;
}
/* Add left-over byte, if any */
if (count > 0) {
/* Make sure that the left-over byte is added correctly both
* with little and big endian hosts */
uint16_t tmp = 0;
*(unsigned char *) (&tmp) = * (unsigned char *) source;
sum += tmp;
}
/* Fold 32-bit sum to 16 bits */
while (sum >> 16)
sum = (sum & 0xffff) + (sum >> 16);
return ~sum;
}
/* Constuct a ip/udp header for a packet, and specify the source and dest
* hardware address */
int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
int source_port, uint32_t dest_ip, int dest_port,
unsigned char *dest_arp, int ifindex)
{
int fd, result = -1;
struct sockaddr_ll dest;
struct udp_dhcp_packet packet;
if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
debug(LOG_ERR, "socket call failed: %s\n", strerror(errno));
goto out;
}
memset(&dest, 0, sizeof(dest));
memset(&packet, 0, sizeof(packet));
dest.sll_family = AF_PACKET;
dest.sll_protocol = htons(ETH_P_IP);
dest.sll_ifindex = ifindex;
dest.sll_halen = 6;
memcpy(dest.sll_addr, dest_arp, 6);
if (bind(fd, (struct sockaddr *)&dest, sizeof(struct sockaddr_ll)) < 0) {
debug(LOG_ERR, "bind call failed: %s\n", strerror(errno));
goto out_fd;
}
packet.ip.protocol = IPPROTO_UDP;
packet.ip.saddr = source_ip;
packet.ip.daddr = dest_ip;
packet.udp.source = htons(source_port);
packet.udp.dest = htons(dest_port);
/* cheat on the psuedo-header */
packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage));
packet.ip.tot_len = packet.udp.len;
memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
packet.udp.check = checksum(&packet, sizeof(struct udp_dhcp_packet));
packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
packet.ip.ihl = sizeof(packet.ip) >> 2;
packet.ip.version = IPVERSION;
packet.ip.ttl = IPDEFTTL;
packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip));
result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0,
(struct sockaddr *)&dest, sizeof dest);
if (result <= 0) {
debug(LOG_ERR, "write on socket failed: %s\n",
strerror(errno));
}
out_fd:
close(fd);
out:
return result;
}
/* Let the kernel do all the work for packet generation */
int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
int source_port, uint32_t dest_ip, int dest_port)
{
int n = 1, fd, result = -1;
struct sockaddr_in client;
if ((fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
goto out;
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == -1)
goto out_fd;
memset(&client, 0, sizeof(client));
client.sin_family = AF_INET;
client.sin_port = htons(source_port);
client.sin_addr.s_addr = source_ip;
if (bind(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
goto out_fd;
memset(&client, 0, sizeof(client));
client.sin_family = AF_INET;
client.sin_port = htons(dest_port);
client.sin_addr.s_addr = dest_ip;
if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
goto out_fd;
result = write(fd, payload, sizeof(struct dhcpMessage));
out_fd:
close(fd);
out:
return result;
}

41
ndhc/packet.h Normal file
View File

@ -0,0 +1,41 @@
#ifndef _PACKET_H
#define _PACKET_H
#include <netinet/udp.h>
#include <netinet/ip.h>
struct dhcpMessage {
uint8_t op;
uint8_t htype;
uint8_t hlen;
uint8_t hops;
uint32_t xid;
uint16_t secs;
uint16_t flags;
uint32_t ciaddr;
uint32_t yiaddr;
uint32_t siaddr;
uint32_t giaddr;
uint8_t chaddr[16];
uint8_t sname[64];
uint8_t file[128];
uint32_t cookie;
uint8_t options[308]; /* 312 - cookie */
};
struct udp_dhcp_packet {
struct iphdr ip;
struct udphdr udp;
struct dhcpMessage data;
};
void init_header(struct dhcpMessage *packet, char type);
int get_packet(struct dhcpMessage *packet, int fd);
uint16_t checksum(void *addr, int count);
int raw_packet(struct dhcpMessage *payload, uint32_t source_ip, int source_port,
uint32_t dest_ip, int dest_port, unsigned char *dest_arp, int ifindex);
int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip, int source_port,
uint32_t dest_ip, int dest_port);
#endif

67
ndhc/rootcap.c Normal file
View File

@ -0,0 +1,67 @@
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <grp.h>
#include "log.h"
static void set_cap(uid_t uid, gid_t gid, char *captxt)
{
cap_t caps;
if (!captxt) {
log_line(LOG_ERR, "FATAL - set_cap: captxt == NULL\n");
exit(EXIT_FAILURE);
}
if (prctl(PR_SET_KEEPCAPS, 1)) {
log_line(LOG_ERR, "FATAL - set_cap: prctl() failed\n");
exit(EXIT_FAILURE);
}
if (setgroups(0, NULL) == -1) {
log_line(LOG_ERR, "FATAL - set_cap: setgroups() failed\n");
exit(EXIT_FAILURE);
}
if (setegid(gid) == -1 || seteuid(uid) == -1) {
log_line(LOG_ERR, "FATAL - set_cap: seteuid() failed\n");
exit(EXIT_FAILURE);
}
caps = cap_from_text(captxt);
if (!caps) {
log_line(LOG_ERR, "FATAL - set_cap: cap_from_text() failed\n");
exit(EXIT_FAILURE);
}
if (cap_set_proc(caps) == -1) {
log_line(LOG_ERR, "FATAL - set_cap: cap_set_proc() failed\n");
exit(EXIT_FAILURE);
}
cap_free(caps);
}
void drop_root(uid_t uid, gid_t gid, char *captxt)
{
if (!captxt) {
log_line(LOG_ERR, "FATAL - drop_root: captxt == NULL\n");
exit(EXIT_FAILURE);
}
if (uid == 0 || gid == 0) {
log_line(LOG_ERR, "FATAL - drop_root: attempt to drop root to root?\n");
exit(EXIT_FAILURE);
}
set_cap(uid, gid, captxt);
if (setregid(gid, gid) == -1 || setreuid(uid, uid) == -1) {
log_line(LOG_ERR, "FATAL - drop_root: failed to drop root!\n");
exit(EXIT_FAILURE);
}
}

2
ndhc/rootcap.h Normal file
View File

@ -0,0 +1,2 @@
void drop_root(uid_t uid, gid_t gid, char *captxt);

258
ndhc/script.c Normal file
View File

@ -0,0 +1,258 @@
/* script.c
*
* Functions to call the interface change daemon
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
* Nicholas Kain <njk@nozspamz.aerifal.cx> 2004
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <errno.h>
#include "options.h"
#include "dhcpd.h"
#include "dhcpc.h"
#include "packet.h"
#include "options.h"
#include "log.h"
#include "script.h"
static int snprintip(char *dest, size_t size, unsigned char *ip) {
if (!dest) return -1;
return snprintf(dest, size, "%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3]);
}
static int sprintip(char *dest, size_t size, char *pre, unsigned char *ip) {
if (!dest) return -1;
return snprintf(dest, size, "%s%d.%d.%d.%d", pre, ip[0], ip[1], ip[2], ip[3]);
}
/* Fill dest with the text of option 'option'. */
static void fill_options(char *dest, unsigned char *option, struct dhcp_option *type_p, unsigned int maxlen)
{
int type, optlen;
uint16_t val_u16;
int16_t val_s16;
uint32_t val_u32;
int32_t val_s32;
int len = option[OPT_LEN - 2];
char *odest;
odest = dest;
dest += snprintf(dest, maxlen, "%s=", type_p->name);
type = type_p->flags & TYPE_MASK;
optlen = option_lengths[type];
for(;;) {
switch (type) {
case OPTION_IP_PAIR:
dest += sprintip(dest, maxlen - (dest - odest), "", option);
*(dest++) = '/';
option += 4;
optlen = 4;
case OPTION_IP: /* Works regardless of host byte order. */
dest += sprintip(dest, maxlen - (dest - odest), "", option);
break;
case OPTION_BOOLEAN:
dest += snprintf(dest, maxlen - (dest - odest), *option ? "yes " : "no ");
break;
case OPTION_U8:
dest += snprintf(dest, maxlen - (dest - odest), "%u ", *option);
break;
case OPTION_U16:
memcpy(&val_u16, option, 2);
dest += snprintf(dest, maxlen - (dest - odest), "%u ", ntohs(val_u16));
break;
case OPTION_S16:
memcpy(&val_s16, option, 2);
dest += snprintf(dest, maxlen - (dest - odest), "%d ", ntohs(val_s16));
break;
case OPTION_U32:
memcpy(&val_u32, option, 4);
dest += snprintf(dest, maxlen - (dest - odest), "%lu ", (unsigned long) ntohl(val_u32));
break;
case OPTION_S32:
memcpy(&val_s32, option, 4);
dest += snprintf(dest, maxlen - (dest - odest), "%ld ", (long) ntohl(val_s32));
break;
case OPTION_STRING:
if ( (maxlen - (dest - odest)) < (unsigned)len) return;
memcpy(dest, option, len);
dest[len] = '\0';
return; /* Short circuit this case */
}
option += optlen;
len -= optlen;
if (len <= 0) break;
}
}
static int open_ifch(void) {
int sockfd, ret;
struct sockaddr_un address =
{
.sun_family = AF_UNIX,
.sun_path = "ifchange"
};
sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
ret = connect(sockfd, (struct sockaddr *)&address, sizeof(address));
if (ret == -1) {
log_line(LOG_ERR, "unable to connect to ifchd!\n");
exit(EXIT_FAILURE);
}
return sockfd;
}
static void sockwrite(int fd, const void *buf, size_t count)
{
int ret;
sockwrite_again:
ret = write(fd, buf, count);
if (ret == -1) {
if (errno == EAGAIN)
goto sockwrite_again;
log_line(LOG_ERR, "error while writing to unix socket!\n");
exit(EXIT_FAILURE);
}
if (ret < 0) ret = 0;
if ((unsigned int)ret < strlen(buf)) {
log_line(LOG_ERR, "incomplete write!\n");
}
debug(LOG_INFO, "writing: %s\n", (char *)buf);
}
static void deconfig_if(void)
{
int sockfd;
char buf[256];
memset(buf, '\0', sizeof buf);
sockfd = open_ifch();
snprintf(buf, sizeof buf, "interface:%s:",
client_config.interface);
sockwrite(sockfd, buf, strlen(buf));
snprintf(buf, sizeof buf, "ip:0.0.0.0:");
sockwrite(sockfd, buf, strlen(buf));
close(sockfd);
exit(EXIT_SUCCESS);
}
static void translate_option(int sockfd, struct dhcpMessage *packet, int opt) {
char buf[256], buf2[256];
unsigned char *p;
int i;
if (!packet) return;
memset(buf, '\0', sizeof(buf));
memset(buf2, '\0', sizeof(buf2));
p = get_option(packet, options[opt].code);
fill_options(buf2, p, &options[opt], sizeof(buf2) - 1);
snprintf(buf, sizeof buf, "%s:", buf2);
for (i=0; i<256; i++) {
if (buf[i] == '\0') break;
if (buf[i] == '=') {
buf[i] = ':';
break;
}
}
sockwrite(sockfd, buf, strlen(buf));
}
static void bound_if(struct dhcpMessage *packet)
{
int sockfd;
char buf[256], buf2[256];
char ip[32];
if (!packet) return;
memset(buf, '\0', sizeof(buf));
memset(ip, '\0', sizeof(ip));
memset(buf2, '\0', sizeof(buf2));
sockfd = open_ifch();
snprintf(buf, sizeof buf, "interface:%s:", client_config.interface);
sockwrite(sockfd, buf, strlen(buf));
snprintip(ip, sizeof ip, (unsigned char *) &packet->yiaddr);
snprintf(buf, sizeof buf, "ip:%s:", ip);
sockwrite(sockfd, buf, strlen(buf));
translate_option(sockfd, packet, 0);
translate_option(sockfd, packet, 2);
translate_option(sockfd, packet, 5);
translate_option(sockfd, packet, 9);
translate_option(sockfd, packet, 11);
translate_option(sockfd, packet, 15);
translate_option(sockfd, packet, 16);
translate_option(sockfd, packet, 17);
close(sockfd);
exit(EXIT_SUCCESS);
}
void run_script(struct dhcpMessage *packet, int mode)
{
int pid;
pid = fork();
if (pid) {
waitpid(pid, NULL, 0);
return;
} else if (pid == 0) {
switch (mode) {
case SCRIPT_DECONFIG:
deconfig_if();
break;
case SCRIPT_BOUND:
bound_if(packet);
break;
case SCRIPT_RENEW:
bound_if(packet);
break;
case SCRIPT_NAK:
deconfig_if();
break;
default:
break;
}
log_line(LOG_ERR, "invalid script mode: %d\n", mode);
exit(EXIT_FAILURE);
}
}

13
ndhc/script.h Normal file
View File

@ -0,0 +1,13 @@
#ifndef _SCRIPT_H
#define _SCRIPT_H
enum {
SCRIPT_DECONFIG = 0,
SCRIPT_BOUND = 1,
SCRIPT_RENEW = 2,
SCRIPT_NAK = 4
};
void run_script(struct dhcpMessage *packet, int mode);
#endif

155
ndhc/socket.c Normal file
View File

@ -0,0 +1,155 @@
/*
* socket.c -- DHCP server client/server socket creation
*
* udhcp client/server
* Copyright (C) 1999 Matthew Ramsay <matthewr@moreton.com.au>
* Chris Trew <ctrew@moreton.com.au>
*
* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
*
* Cleanup and fixes, Nicholas Kain <njk@n0sPaM.kain.us> 2004
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <errno.h>
#include <features.h>
#include <netpacket/packet.h>
#include <net/ethernet.h>
#include "log.h"
#include "nstrl.h"
int read_interface(char *interface, int *ifindex, uint32_t *addr,
unsigned char *arp)
{
int fd, ret = -1;
struct ifreq ifr;
struct sockaddr_in *our_ip;
memset(&ifr, 0, sizeof(struct ifreq));
if((fd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) == -1) {
log_line(LOG_ERR, "socket failed!: %s\n", strerror(errno));
goto out;
}
ifr.ifr_addr.sa_family = AF_INET;
strlcpy(ifr.ifr_name, interface, IFNAMSIZ);
if (addr) {
if (ioctl(fd, SIOCGIFADDR, &ifr)) {
log_line(LOG_ERR, "Couldn't get IP for %s.\n", strerror(errno));
goto out_fd;
}
our_ip = (struct sockaddr_in *) &ifr.ifr_addr;
*addr = our_ip->sin_addr.s_addr;
debug(LOG_INFO, "%s (our ip) = %s\n", ifr.ifr_name,
inet_ntoa(our_ip->sin_addr));
}
if (ioctl(fd, SIOCGIFINDEX, &ifr)) {
log_line(LOG_ERR, "SIOCGIFINDEX failed!: %s\n", strerror(errno));
goto out_fd;
}
debug(LOG_INFO, "adapter index %d\n", ifr.ifr_ifindex);
*ifindex = ifr.ifr_ifindex;
if (ioctl(fd, SIOCGIFHWADDR, &ifr)) {
log_line(LOG_ERR, "Couldn't get MAC for %s\n", strerror(errno));
goto out_fd;
}
memcpy(arp, ifr.ifr_hwaddr.sa_data, 6);
debug(LOG_INFO, "adapter hardware address %02x:%02x:%02x:%02x:%02x:%02x\n",
arp[0], arp[1], arp[2], arp[3], arp[4], arp[5]);
ret = 0;
out_fd:
close(fd);
out:
return ret;
}
int listen_socket(unsigned int ip, int port, char *inf)
{
struct ifreq interface;
int fd;
struct sockaddr_in addr;
int n = 1;
debug(LOG_INFO, "Opening listen socket on 0x%08x:%d %s\n", ip, port, inf);
if ((fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
debug(LOG_ERR, "socket call failed: %s\n", strerror(errno));
goto out;
}
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr.s_addr = ip;
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&n, sizeof n) == -1)
goto out_fd;
if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, (char *)&n, sizeof n) == -1)
goto out_fd;
strlcpy(interface.ifr_ifrn.ifrn_name, inf, IFNAMSIZ);
if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
(char *)&interface, sizeof interface) < 0)
goto out_fd;
if (bind(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr)) == -1)
goto out_fd;
return fd;
out_fd:
close(fd);
out:
return -1;
}
int raw_socket(int ifindex)
{
int fd;
struct sockaddr_ll sock;
debug(LOG_INFO, "Opening raw socket on ifindex %d\n", ifindex);
if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
debug(LOG_ERR, "socket call failed: %s\n", strerror(errno));
goto out;
}
sock.sll_family = AF_PACKET;
sock.sll_protocol = htons(ETH_P_IP);
sock.sll_ifindex = ifindex;
if (bind(fd, (struct sockaddr *) &sock, sizeof(sock)) < 0) {
debug(LOG_ERR, "bind call failed: %s\n", strerror(errno));
goto out_fd;
}
return fd;
out_fd:
close(fd);
out:
return -1;
}

9
ndhc/socket.h Normal file
View File

@ -0,0 +1,9 @@
/* socket.h */
#ifndef _SOCKET_H
#define _SOCKET_H
int read_interface(char *interface, int *ifindex, uint32_t *addr, unsigned char *arp);
int listen_socket(unsigned int ip, int port, char *inf);
int raw_socket(int ifindex);
#endif

46
nstrl.c Normal file
View File

@ -0,0 +1,46 @@
/* nstrl.c - strlcpy/strlcat implementation
(C) 2003 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <unistd.h>
#ifndef HAVE_STRLCPY
size_t strlcpy (char *dest, char *src, size_t size)
{
register char *d = dest, *s = src;
for (; *s != '\0' && size > 0; size--, d++, s++)
*d = *s;
*d = '\0';
return (d - dest) + (s - src);
}
size_t strlcat (char *dest, char *src, size_t size)
{
register char *d = dest, *s = src;
for (; size > 0 && *d != '\0'; size--, d++);
for (; *s != '\0' && size > 0; size--, d++, s++)
*d = *s;
*d = '\0';
return (d - dest) + (s - src);
}
#endif

23
nstrl.h Normal file
View File

@ -0,0 +1,23 @@
/* nstrl.h - header file for strlcpy/strlcat implementation
(C) 2003 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifndef NJK_HAVE_STRL_
#define NJK_HAVE_STRL_ 1
size_t strlcpy (char *dest, char *src, size_t size);
size_t strlcat (char *dest, char *src, size_t size);
#endif

45
pidfile.c Normal file
View File

@ -0,0 +1,45 @@
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include "defines.h"
#include "log.h"
void write_pid(char *file) {
FILE *f;
char buf[MAXLINE];
if (!file)
return;
f = fopen(file, "w");
if (f == NULL) {
log_line("FATAL - failed to open pid file \"%s\"!\n", file);
exit(EXIT_FAILURE);
}
snprintf(buf, sizeof buf, "%i", (unsigned int)getpid());
fwrite(buf, sizeof (char), strlen(buf), f);
if (fclose(f) != 0) {
log_line("FATAL - failed to close pid file \"%s\"!\n", file);
exit(EXIT_FAILURE);
}
}
/* Return 0 on success, -1 on failure. */
int file_exists(char *file, char *mode) {
FILE *f;
if (file == NULL || mode == NULL)
return -1;
f = fopen(file, mode);
if (f == NULL)
return -1;
fclose(f);
return 0;
}

6
pidfile.h Normal file
View File

@ -0,0 +1,6 @@
#ifndef NJK_PIDFILE_H_
#define NJK_PIDFILE_H_ 1
void write_pid(char *file);
int file_exists(char *file, char *mode);
#endif

46
signals.c Normal file
View File

@ -0,0 +1,46 @@
/* signals.c - abstracts signal handling
(C) 2004 Nicholas J. Kain <njk@aerifal.cx>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include "log.h"
void hook_signal(int signum, void (*fn)(int), int flags) {
struct sigaction new_action;
new_action.sa_handler = fn;
sigemptyset(&new_action.sa_mask);
new_action.sa_flags = flags;
if (sigaction(signum, &new_action, NULL)) {
log_line("FATAL - failed to hook signal %i\n", signum);
exit(EXIT_FAILURE);
}
}
void disable_signal(int signum) {
struct sigaction new_action;
new_action.sa_handler = SIG_IGN;
sigemptyset(&new_action.sa_mask);
if (sigaction(signum, &new_action, NULL)) {
log_line("FATAL - failed to ignore signal %i\n", signum);
exit(EXIT_FAILURE);
}
}

6
signals.h Normal file
View File

@ -0,0 +1,6 @@
#ifndef NJK_SIGNALS_H_
#define NJK_SIGNALS_H_ 1
void hook_signal(int signum, void (*fn)(int), int flags);
void disable_signal(int signum);
#endif

71
strlist.c Normal file
View File

@ -0,0 +1,71 @@
#include <unistd.h>
#include <malloc.h>
#include <string.h>
#include "nstrl.h"
#include "strlist.h"
void add_to_strlist(char *name, strlist_t **list)
{
strlist_t *item, *t;
char *s;
unsigned int len;
if (!list || !name)
return;
len = strlen(name);
if (!len)
return;
s = malloc(len + 1);
if (!s)
return;
strlcpy(s, name, len + 1);
item = malloc(sizeof (strlist_t));
if (!item)
goto out0;
item->str = s;
item->next = NULL;
if (!*list) {
*list = item;
return;
}
for (t = *list; t->next; t = t->next)
if (!t->next) {
t->next = item;
return;
}
free(item); /* should be impossible, but hey */
out0:
free(s);
return;
}
void free_strlist(strlist_t *head)
{
strlist_t *p = head, *q = NULL;
while (p != NULL) {
free(p->str);
q = p;
p = q->next;
free(q);
}
}
void free_stritem(strlist_t **p)
{
strlist_t *q;
if (!p || !*p)
return;
q = (*p)->next;
free((*p)->str);
free(*p);
*p = q;
}

14
strlist.h Normal file
View File

@ -0,0 +1,14 @@
#ifndef NJK_STRLIST_H_
#define NJK_STRLIST_H_ 1
typedef struct
{
char *str;
void *next;
} strlist_t;
void add_to_strlist(char *name, strlist_t **list);
void free_strlist(strlist_t *head);
void free_stritem(strlist_t **p);
#endif