The setpriv executable from util-linux also dumps out information on the
different capability sets known by the kernel. By default, these are the
inheritable capabilities, bounding capabilities and (not yet released)
the ambient capabilities, which have been introduced with Linux 4.3.
This patch introduces the ability to dump the set of inheritable
capabilities.
By default, setpriv(1) identifies capabilities by their human-readable
name, for example 'net_admin'. For unknown capabilities, though, it does
instead use the capability's value, for example 'cap_12', which is
equivalent to 'net_admin'. As there is no kernel interface to retrieve
capability names by their index, we have to declare these ourselves,
which adds to setpriv's size.
To counteract, using the human-readble name has been made configurable.
The following sizes are with the 'FEATURE_SETPRIV_CAPABILITY_NAMES'
enabled:
function old new delta
.rodata 145969 146405 +436
setpriv_main 467 842 +375
capabilities - 304 +304
And with 'FEATURE_SETPRIV_CAPABILITY_NAMES' disabled:
function old new delta
setpriv_main 467 838 +371
.rodata 145969 146101 +132
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Introduce the ability to dump the state of the no-new-privs flag, which
states whethere it is allowed to grant new privileges.
function old new delta
setpriv_main 419 467 +48
.rodata 145926 145969 +43
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
setpriv from util-linux has an option to dump the current state
regarding privilege settings via '--dump'. It prints out information on
the real and effective user and group IDs, supplementary groups, the
no-new-privs flag, the capability sets as well as secure bits.
This patch is the start of supporting this mode. To make introduction of
the '--dump' easier to reason about, its introduction has been split
into multiple patches. This particular one introduces the ability to
print out user and group information of the current process.
function old new delta
setpriv_main 89 322 +233
getresuid - 41 +41
getresgid - 41 +41
static.setpriv_longopts 22 29 +7
packed_usage 31675 31669 -6
------------------------------------------------------------------------------
(add/remove: 4/0 grow/shrink: 2/1 up/down: 322/-6) Total: 316 bytes
Patch by Patrick Steinhardt <ps@pks.im>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The current option parsing logic of setpriv only supports the case where
we want to execute a sub-program and have at most one argument. Refactor
handling of options to solve these shortcomings to make it easy to
support 'setpriv --dump', which does not accept any additional
arguments, as well as the case where additional options are passed to
setpriv. This is done by handling 'argc' ourselves, throwing an error
when no program is specified, as well as introducing an enum for the
different option bitmasks.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
By default, the 'getopt32' call will continue parsing the command line
even after hitting a non-option string. But in setpriv, this should be
avoided, as all parameters following the initial non-option argument are
in fact arguments to the binary that is to be executed by setpriv.
Otherwise, calling e.g. 'busybox setpriv ls -l' would result in an error
due to the unknown parameter "-l".
Fix the issue by passing "+" as the first character in the options
string. This will cause 'getopt32' to stop processing after hitting the
first non-option.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Add a minimal 'setpriv' implementation supporting the NO_NEW_PRIVS bit.
Typical usage:
$ busybox setpriv sudo uname
Linux
$ busybox setpriv --nnp sudo uname
sudo: effective uid is not 0, is /usr/bin/sudo on a file system with
the 'nosuid' option set or an NFS file system without root privileges?
function old new delta
packed_usage 31580 31685 +105
setpriv_main - 87 +87
prctl - 53 +53
static.setpriv_longopts - 22 +22
applet_names 2620 2628 +8
applet_main 1516 1520 +4
------------------------------------------------------------------------------
(add/remove: 5/0 grow/shrink: 3/0 up/down: 279/0) Total: 279 bytes
Signed-off-by: Assaf Gordon <assafgordon@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
