With the Qualys security audit, we began to harden our
treatment of the top rcfile. In particular, the values
read were checked so as to prevent some malicious user
from editing it in order to achieve an evil objective.
However when it came to colors I was surprised to find
that at least one user edited the rcfile for 256-color
support. Unfortunately, our new checks prevented this.
So this commit will provide the means to exploit those
extra colors with no need to manually edit the rcfile.
Reference(s):
https://gitlab.com/procps-ng/procps/issues/96
Signed-off-by: Jim Warner <james.warner@comcast.net>
This guards against rcfile 'Inspect' entries which may
include non-printable characters. While this shouldn't
occur, we have no real control over those crazy users.
[ and, while such data can't be used maliciously, it ]
[ does adversely impact such a user's screen display ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
For our master branch, a Qualys patch referenced below
was reverted as being unwarranted. That original patch
was not applied in this branch so there was no revert.
However, there was 1 specific problem their patch had,
in fact, prevented. Thus, this patch now addresses it.
Reference(s):
. original qualys patch
0109-top-Protect-scat-from-buffer-overflows.patch
Signed-off-by: Jim Warner <james.warner@comcast.net>
Until the Qualys security audit I had never considered
it a possibility that some malicious person might edit
the top config file to achieve some nefarious results.
And while the Qualys approach tended to concentrate on
the symptoms from such an effort, subsequent revisions
more properly concentrated on startup and that rcfile.
This commit completes those efforts with 1 more field.
Signed-off-by: Jim Warner <james.warner@comcast.net>
The command name for running tasks is displayed by top
in a variable length field, so the increase from 16 to
64 bytes was not a problem. However, there's one place
where top is sensitive to length - insp_view_choice().
So, this patch just bumps a buffer used to display it.
Reference(s):
. master branch increase to 64
commit 2cfdbbe897
Signed-off-by: Jim Warner <james.warner@comcast.net>
This will protect some remaining rcfile variables from
a possible manual editing of top's configuration file.
[ and correct two #error related boo-boos introduced ]
[ with the system default rcfile in the commit shown ]
Reference(s):
. introduced /etc/topdefaultrc
commit 55a42ae040
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch addresses a potential (but unlikely) buffer
overflow by reducing, if necessary, a memcpy length by
3 bytes to provide for an eol '\0' and 2 unused buffer
positions which also might receive the '\0' character.
[ note to future analysis tool: just because you see ]
[ binary data being manipulated in the routine, that ]
[ doesn't mean such function was passed binary data! ]
Reference(s):
. original qualys patch
0116-top-Fix-out-of-bounds-read-write-in-show_special.patch
Signed-off-by: Jim Warner <james.warner@comcast.net>
Whereas an original patch (referenced below) addressed
some symptoms related to manually edited config files,
this solution deals with root causes. And it goes much
beyond any single top field by protecting all of top's
fields. Henceforth, a duplicated field is not allowed.
Reference(s):
. original qualys patch
0114-top-Prevent-buffer-overflow-in-calibrate_fields.patch
Signed-off-by: Jim Warner <james.warner@comcast.net>
Rather than validate the window's 'sortindx' each time
it was referenced (as was done in the patch below), we
now ensure the validity just once when the config file
is read. Thereafter, a running top will police bounds.
Reference(s):
. original qualys patch
0102-top-Check-sortindx.patch
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch replaces an original patch referenced below
(omitted under this branch). We now validate variables
'graph_cpus', 'graph_mems' and 'summ_mscale' just once
at startup. Thereafter, top enforces the proper range.
[ we afford the same treatment to that 'task_mscale' ]
[ variable, which was ignored in the original patch. ]
Reference(s):
. original qualys patch
0099-top-Check-graph_cpus-graph_mems-and-summ_mscale.patch
Signed-off-by: Jim Warner <james.warner@comcast.net>
While it's only documented (so far) in commit text and
an occasional email I've tried to maintain some coding
standards primarily for reference/navigation purposes.
They also served, I felt, as useful mental challenges.
Someday I will get around to formerly documenting them
but in the meantime here are the ones for this commit:
. functions are grouped into logical (i hope) sections
. functions & sections are ordered to avoid prototypes
. function names are alphabetical within every section
. all functions & sections must be referenced in top.h
This patch just attempts to honor the above standards,
while also covering this new behavior in the man page.
[ please note that the net result of these 2 patches ]
[ is simply to avoid pathname truncations should our ]
[ limit of 1024 be exceeded. they do not have a role ]
[ in solving the 'local privilege escalation' issue. ]
[ and we can never prevent a user from setting their ]
[ HOME var to a directory writable by some attacker! ]
[ the only real protection for that CVE-2018-1122 is ]
[ those soon to be enhanced rcfile integrity checks, ]
[ achieved through several of the following patches. ]
Reference(s):
. original qualys patch
0097-top-Do-not-default-to-the-cwd-in-configs_read.patch
Signed-off-by: Jim Warner <james.warner@comcast.net>
- Make sure i is at least 1 before "i - 1" and "--i".
- Initialize endpflg (to 0, as it was originally, since it is static)
before the "for" loop (the "break" may leave endpflg uninitialized,
for example).
The safety of the critical function task_show() depends on the sanity of
Screen_cols. Just copy the tests on w_cols to Screen_cols (from the same
function adj_geometry()).
The default action for SIGURG is to ignore the signal, for example.
This is very similar to the patch "ps/display.c: Always exit from
signal_handler()."
---------------------------- adapted for newlib branch
. the 'isBUSY' macro is quite different under newlib
Signed-off-by: Jim Warner <james.warner@comcast.net>
Otherwise they may lead to out-of-bounds writes (snprintf() returns the
number of characters which would have been written if enough space had
been available).
Also, make sure buf is null-terminated after COLPLUSCH has been written.
If the HOME environment variable is not set, or not absolute, use the
home directory returned by getpwuid(getuid()), if set and absolute
(instead of the cwd "."); otherwise, set p_home to NULL.
To keep the changes to a minimum, we rely on POSIX, which requires that
fopen() fails with ENOENT if the pathname (Rc_name) is an empty string.
This integrates well into the existing code, and makes write_rcfile()
work without a change.
Also, it makes the code in configs_read() easier to follow: only set and
use p_home if safe, and only set Rc_name if safe (in all the other cases
it is the empty string, and the fopen() calls fail). Plus, check for
snprintf() truncation (and if it happens, reset Rc_name to the empty
string).
Important note: top.1 should probably be updated, since it mentions the
fallback to the current working directory.
With a little luck, this should be the final tweak for
our support of extra wide characters. Currently, those
characters don't always display the '+' indicator when
they've been truncated. Now, it should always be seen.
[ plus it's done a tad more efficiently via snprintf ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
In addition to exploiting the login user ID provision,
the following miscellaneous changes are also included:
. unnecessary braces have been eliminated from an 'if'
. a comment with case EU_CPU: was corrected to 's_int'
and the associated block of code relocated accordingly
. case EU_CPN: wasn't shared with other enumerators so
reference to 'i' was changed to that actual enumerator
. case EU_SGN: wasn't shared with other enumerators so
reference to 'i' was changed to that actual enumerator
Signed-off-by: Jim Warner <james.warner@comcast.net>
As it turns out, that Ukrainian 'demo' text supporting
the '=' command was 152 bytes long, up from an English
version of 80 bytes. Unfortunately, the buffer used to
format all such strings was insufficient at 128 bytes.
Depending on the width of one's terminal, some strange
result could be experienced when a multi-byte sequence
was truncated. So, this just makes that buffer bigger.
Signed-off-by: Jim Warner <james.warner@comcast.net>
After wrestling with extra wide characters, supporting
languages like zh_CN, sometimes default/minimum column
widths might force a truncation of translated headers.
So, this commit explores one way that such truncations
could be avoided. It is designed so as to have minimal
impact on existing code, ultimately affecting just one
function. But it's off by default via its own #define.
Signed-off-by: Jim Warner <james.warner@comcast.net>
When I recently added extra wide character support for
locales like zh_CN, I didn't worry about some overhead
associated with the new calls to 'mbtowc' & 'wcwidth'.
That's because such overhead was usually incurred with
user interactions, not a normal iterative top display.
There was, however, one area where this overhead would
impact the normal iterative top mode - that's with the
Summary display. So I peeked at the glibc source code.
As it turns out, the costs of executing those 'mbtowc'
and 'wcwidth' functions were not at all insignificant.
So, this patch will avoid them in the vast majority of
instances, while still enabling extra wide characters.
Signed-off-by: Jim Warner <james.warner@comcast.net>
There is (should be) no justification for changing the
width of the percentage columns (%CPU, %MEM) depending
on the BOOST_PERCNT #define. So this patch will ensure
that both columns are fixed at their former maximum 5.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Back when top was refactored to support UTF-8 encoding
it was acknowledged that languages like zh_CN were not
supported. That was because a single 'character' might
require more than a single 'column' when it's printed.
Well I've now figured out how to accommodate languages
like that. My adaptation is represented in this patch.
[ and just in case someone wishes to avoid the extra ]
[ runtime costs, a #define OFF_XTRAWIDE is included. ]
Along the way, I've cleaned up some miscellaneous code
supporting the 'Inspect' feature so that the rightmost
screen column was always used rather than being blank.
[ interestingly, my xterm & urxvt terminal emulators ]
[ are able to split extra wide characters then print ]
[ 1/2 of such graphics in the last column. the gnome ]
[ terminal emulator does not duplicate such behavior ]
[ but prints 1 extra character in same width window. ]
Reference(s):
. Sep, 2017 - original utf8 support
commit 9773c56add
Signed-off-by: Jim Warner <james.warner@comcast.net>
When the new approach for startup defaults was adopted
in the reference below, a file might be left open that
technically should be closed. This situation arises in
the unlikely event the #define RCFILE_NOERR is active.
Without that #define, the program will exit early thus
rendering the open file issue moot. However, even with
that #define there was no real harm with an open file.
It simply meant a 2nd FILE struct would have been used
when, or if, the rcfile was written via a 'W' command.
Anyway, this patch ensures such a file will be closed.
Reference(s):
. Dec, 2017 - /etc/topdefaultrc introduced
commit 55a42ae040
Signed-off-by: Jim Warner <james.warner@comcast.net>
Those references below offer more detail regarding the
default startup changes beginning with version 3.3.10.
It is important to remember that all such changes were
supposed to impact only new users or users who had not
saved the personal config file (via that 'W' command).
However, I introduced a bug wherein the rcfile was not
fully honored. This gave the changes a bad reputation.
That bug was corrected in release 3.3.11 but the issue
of default startup options keeps resurfacing. And it's
clear there's no consensus on what should be included.
Our --disable-modern-top configure option is of little
help since it remains an all-or-nothing approach. What
we need is an answer offering unlimited customization.
So, this commit will provide distribution packagers or
system administrators with a much more flexible way to
set their own preferred startup default configuration.
A new rcfile is being introduced: '/etc/topdefaultrc',
whose format/content is the same as a personal rcfile.
Thus once a 'proper' enterprise configuration has been
established and saved via 'W', it can be copied to the
/etc/ directory. Thereafter, startup in the absence of
a saved rcfile will use that configuration as default.
Now if a distribution packager or system administrator
wishes to expose their users to some of top's advanced
capabilities they can do so gradually. Perhaps setting
up graph mode for summary area task and memory display
while retaining the %CPU sort could be tried. Or maybe
showing colors, but better customized for a particular
terminal emulator. Such possibilities are now endless.
[ in exploiting this new capability, i hope that the ]
[ other windows (alt display mode) aren't overlooked ]
Reference(s):
. Sep, 2014 - Not fully honoring rcfile bug discussed
https://www.freelists.org/post/procps/top-saved-rcfile-bug
. Oct, 2014 - Attempt to defend new startup defaults
https://bugzilla.redhat.com/show_bug.cgi?id=1153049
. Jul, 2015 - Forest vs. %CPU views discussion
https://gitlab.com/procps-ng/procps/issues/6
. Oct, 2017 - Question the use of --disable-modern-top
https://bugzilla.redhat.com/show_bug.cgi?id=1499410
. Oct, 2017 - Forest vs. %CPU views discussion again
https://www.freelists.org/post/procps/Forest-mode-by-default-in-top-seems-a-bit-strange
. Dec, 2017 - Rehash of 3.3.10 startup defaults change
https://gitlab.com/procps-ng/procps/issues/78
Signed-off-by: Jim Warner <james.warner@comcast.net>
With the library having now normalized errno handling,
perhaps it is time at least one program took advantage
of it. So, instead of printing just a message with the
programs's line number, top will now also provide that
associated errno string text, compliments of strerror.
[ with those newlib functions returning NULL, we can ]
[ use errno directly in strerror. for the ones which ]
[ yield an int, all we need do is invert such return ]
[ values before passing it to the strerror function. ]
Reference(s):
Signed-off-by: Jim Warner <james.warner@comcast.net>
And I thought those strange characters I saw with only
certain translations in Fields Management descriptions
were resulting from my terminal emulator deficiencies.
Turns out that ol' top wasn't addressing possibilities
of such descriptions ending with multi-byte sequences.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Initially, I was going to ignore that coverity warning
CID #177876. But, since top may be running SETUID it's
best if it can be avoided instead. The fix was simple.
We'll trade the access() call for a real fopen() call.
This time-of-check-time-of-use warning should go away.
------------------------------------------------------
When XDG support was originally introduced in top, the
author made a poor choice in access(). A real question
that needed asking was 'does the file exist'. However,
the question that was asked was 'can this real user ID
or this real group ID access the file'. Then, when the
fopen() is finally issued, top would use the effective
user ID or the effective group ID to access that file.
That's what opened the potential TOCTOU vulnerability,
which was important only if top was running SUID/SGID.
Signed-off-by: Jim Warner <james.warner@comcast.net>
By eliminating the call to 'fmtmk', the 'utf8_justify'
function could more easily be used in libproc someday.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Gosh, all this time we used indents of 4 spaces, not 3
spaces which were always the top standard indentation.
[ and we made our 'utf8_embody' a little more robust ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch better exploits short-circuit evaluation in
two 'if' tests. In every case, the 1st of 2 conditions
in each 'if' test must take place but it always proves
true with each iteration for 1 of the 'if' statements.
Thus, the 2nd condition will have to be evaluated too.
By reordering 2 tests in each 'if', we can ensure that
the 2nd condition will then be tested much less often.
Signed-off-by: Jim Warner <james.warner@comcast.net>
Upon reflection, there was absolutely no justification
for that call to strlen() which was then followed by a
call to snprintf(). The latter provides this needed #.
[ also make that 'delta' value a little more visible ]
[ instead of hiding it at the end of a its code line ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
Before top was modified to exploit the new <pids> api,
there was protection in that task_show() makeVAR macro
to avoid multiple evaluation of this macro's argument.
But, in that commit referenced below, such a safeguard
was lost. This commit simply restores proper behavior.
Reference(s);
. offending change
commit 77dc22b910
Signed-off-by: Jim Warner <james.warner@comcast.net>
Well, for some strange unknown reason it happened in a
commit referenced below. But this patch reverts it and
puts this newlib scale_mem on par with the master guy.
[ a little more research reveals that it should have ]
[ been reverted in the 2nd commit shown. that's when ]
[ types were fixed after XTRA_PROCPS_DEBUG was used. ]
Reference(s):
. when 'unsigned' qualifier lost
commit 911083bf76
. when 'unsigned' qualifier not restored
commit 105058ae2d
. when XTRA_PROCPS_DEBUG validation introduced
commit e3270d463d
Signed-off-by: Jim Warner <james.warner@comcast.net>
With the help of our Swedish translator, hopefully the
final buglet has now been vanquished in the multi-byte
translation support. This one was a real nasty bugger.
Although it didn't occur with every terminal emulator,
occasionally random text lines were being chopped off.
As it turns out, those terminals were blameless. There
were two separate places in top's show_special routine
where potential multi-byte sequences were inadequately
addressed. Solution: exploit existing utf-8 functions.
[ it also became apparent that the translation hints ]
[ in the top_nls module were deficient. so a special ]
[ caution was added regarding the final line of txt. ]
Reference(s):
https://gitlab.com/procps-ng/procps/issues/68
Signed-off-by: Jim Warner <james.warner@comcast.net>
