* parsing.c (substr): Handle tail < head.
This started when I noticed some cgit segfaults on savannah.gnu.org.
Finding the offending URL/commit and then constructing a stand-alone
reproducer were far more time-consuming than writing the actual patch.
The problem arises with a commit like this, in which the user name
part of the "Author" field is empty:
$ git log -1
commit 6f3f41d73393278f3ede68a2cb1e7a2a23fa3421
Author: <T at h.or>
Date: Mon Apr 23 22:29:16 2012 +0200
Here's what happens:
(this is due to buf=malloc(0); strncpy (buf, head, -1);
where "head" may point to plenty of attacker-specified non-NUL bytes,
so we can overwrite a zero-length heap buffer with arbitrary data)
Invalid write of size 1
at 0x4A09361: strncpy (mc_replace_strmem.c:463)
by 0x408977: substr (parsing.c:61)
by 0x4089EF: parse_user (parsing.c:73)
by 0x408D10: cgit_parse_commit (parsing.c:153)
by 0x40A540: cgit_mk_refinfo (shared.c:171)
by 0x40A581: cgit_refs_cb (shared.c:181)
by 0x43DEB3: do_for_each_ref (refs.c:690)
by 0x41075E: cgit_print_branches (ui-refs.c:191)
by 0x416EF2: cgit_print_summary (ui-summary.c:56)
by 0x40780A: summary_fn (cmd.c:120)
by 0x40667A: process_request (cgit.c:544)
by 0x404078: cache_process (cache.c:322)
Address 0x4c718d0 is 0 bytes after a block of size 0 alloc'd
at 0x4A0884D: malloc (vg_replace_malloc.c:263)
by 0x455C85: xmalloc (wrapper.c:35)
by 0x40894C: substr (parsing.c:60)
by 0x4089EF: parse_user (parsing.c:73)
by 0x408D10: cgit_parse_commit (parsing.c:153)
by 0x40A540: cgit_mk_refinfo (shared.c:171)
by 0x40A581: cgit_refs_cb (shared.c:181)
by 0x43DEB3: do_for_each_ref (refs.c:690)
by 0x41075E: cgit_print_branches (ui-refs.c:191)
by 0x416EF2: cgit_print_summary (ui-summary.c:56)
by 0x40780A: summary_fn (cmd.c:120)
by 0x40667A: process_request (cgit.c:544)
Invalid write of size 1
at 0x4A09400: strncpy (mc_replace_strmem.c:463)
by 0x408977: substr (parsing.c:61)
by 0x4089EF: parse_user (parsing.c:73)
by 0x408D10: cgit_parse_commit (parsing.c:153)
by 0x40A540: cgit_mk_refinfo (shared.c:171)
by 0x40A581: cgit_refs_cb (shared.c:181)
by 0x43DEB3: do_for_each_ref (refs.c:690)
by 0x41075E: cgit_print_branches (ui-refs.c:191)
by 0x416EF2: cgit_print_summary (ui-summary.c:56)
by 0x40780A: summary_fn (cmd.c:120)
by 0x40667A: process_request (cgit.c:544)
by 0x404078: cache_process (cache.c:322)
Address 0x4c7192b is not stack'd, malloc'd or (recently) free'd
Invalid write of size 1
at 0x4A0940E: strncpy (mc_replace_strmem.c:463)
by 0x408977: substr (parsing.c:61)
by 0x4089EF: parse_user (parsing.c:73)
by 0x408D10: cgit_parse_commit (parsing.c:153)
by 0x40A540: cgit_mk_refinfo (shared.c:171)
by 0x40A581: cgit_refs_cb (shared.c:181)
by 0x43DEB3: do_for_each_ref (refs.c:690)
by 0x41075E: cgit_print_branches (ui-refs.c:191)
by 0x416EF2: cgit_print_summary (ui-summary.c:56)
by 0x40780A: summary_fn (cmd.c:120)
by 0x40667A: process_request (cgit.c:544)
by 0x404078: cache_process (cache.c:322)
Address 0x4c7192d is not stack'd, malloc'd or (recently) free'd
Process terminating with default action of signal 11 (SIGSEGV)
Access not within mapped region at address 0x502F000
at 0x4A09400: strncpy (mc_replace_strmem.c:463)
by 0x408977: substr (parsing.c:61)
by 0x4089EF: parse_user (parsing.c:73)
by 0x408D10: cgit_parse_commit (parsing.c:153)
by 0x40A540: cgit_mk_refinfo (shared.c:171)
by 0x40A581: cgit_refs_cb (shared.c:181)
by 0x43DEB3: do_for_each_ref (refs.c:690)
by 0x41075E: cgit_print_branches (ui-refs.c:191)
by 0x416EF2: cgit_print_summary (ui-summary.c:56)
by 0x40780A: summary_fn (cmd.c:120)
by 0x40667A: process_request (cgit.c:544)
by 0x404078: cache_process (cache.c:322)
This happens when tail - head == -1 here:
(parsing.c)
char *substr(const char *head, const char *tail)
{
char *buf;
buf = xmalloc(tail - head + 1);
strncpy(buf, head, tail - head);
buf[tail - head] = '\0';
return buf;
}
char *parse_user(char *t, char **name, char **email, unsigned long *date)
{
char *p = t;
int mode = 1;
while (p && *p) {
if (mode == 1 && *p == '<') {
*name = substr(t, p - 1);
t = p;
mode++;
} else if (mode == 1 && *p == '\n') {
The fix is to handle the case of (tail < head) before calling xmalloc,
thus avoiding passing an invalid value to xmalloc.
And here's the reproducer:
It was tricky to reproduce, because git prohibits use of an empty "name"
in a commit ID. To construct the offending commit, I had to resort to
using "git hash-object".
git init -q foo &&
( cd foo &&
echo a > j && git add . && git ci -q --author='au <T at h.or>' -m. . &&
h=$(git cat-file commit HEAD|sed 's/au //' \
|git hash-object -t commit -w --stdin) &&
git co -q -b test $h &&
git br -q -D master &&
git br -q -m test master)
git clone -q --bare foo foo.git
cat <<EOF > in
repo.url=foo.git
repo.path=foo.git
EOF
CGIT_CONFIG=in QUERY_STRING=url=foo.git valgrind ./cgit
The valgrind output is what you see above.
AFAICS, this is not exploitable thanks (ironically) to the use of strncpy.
Since that -1 translates to SIZE_MAX and this is strncpy, not only does it
copy whatever is in "head" (up to first NUL), but it also writes
SIZE_MAX - strlen(head) NUL bytes into the destination buffer, and that
latter is guaranteed to evoke a segfault. Since cgit is single-threaded,
AFAICS, there is no way that the buffer clobbering can be turned into
an exploit.
Since cgit snapshots of tags are often used for releases, we don't
want the rarely used feature of the gzip compressor that includes
an embedded timestamp into the archive, since this makes each tarball
of the same (potentially signed) tag different.
This commit refactors the archive handling code a bit so that each
different format is able to run with an arbitrary argv for the filter.
Add two options, one for doing the ordinary name sorts in a
case-insensitive manner, and another for choosing to sort repos in each
section by age instead of by name.
Don't bother with 'body' and 'div#cgit form', since
everything is wrapped in 'div#cgit' already.
Removing these two types makes embedding even easier.
Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
improves readability when embedding into a page that
has the text color set to a different color
Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
When embedding cgit in other pages, the logo alignment needs to be
specified to avoid any css rules from the embedding page to make the
page look bad.
Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
ctx.qry.head can be NULL in some cases due to bad requests
by weird bots. I managed to reproduce with:
PATH_INFO=/repo.git/shop.php QUERY_STRING=id=
Signed-off-by: Eric Wong <normalperson@yhbt.net>
**L would have worked well too. Depending on the distribution sizeof *L
may return 8 instead of 4. **L is preferable, but since we don't expect
this datatype to change very often, sizeof int is less subtle and easier
to understand.
Signed-off-by: Jamie Couture <jamie.couture@gmail.com>
When a repository is empty, the ATOM feed link is written in the header,
but this involves formatting ctx->qry.head which is NULL in this case.
With glibc, vsnprintf formats "%s" with a NULL input as "(null)" but on
Solaris this results in a segmentation fault. Since we don't have a
meaningful head for the atom feed in an empty repository, it's simplest
not to write out the link element at all.
Signed-off-by: John Keeping <john@metanate.com>
The git tarballs are currently not available from kernel.org, so for now
the makefile will download autogenerated tarballs from cgit.
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
When side-by-side-diffs=1 was set in cgitrc, specifying 'ss=0' in the
querystring would not set the 'unified' option as active in the dropdown
box used to select diffmode.
When side-by-side-diffs=1 was set in cgitrc, specyfing 'ss=0' in the query-
string would not switch to unified diffs. This patch fixes the issue by
introducing a separate variable to track the occurrence of "ss" in the
querystring.
When the repolist is paged, the page-links are missing the sort parameter,
causing the initial page to be custom sorted, but any clicked page will
then be with the default sort order again.
Printing deferred line changes for files containing long lines would
cause a segfault.
- limit LCS table size: 128x128.
- move LCS table to global context: avoid allocating/freeing memory
for every deferred line change.
Signed-off-by: Jamie Couture <jamie.couture@gmail.com>
Some setenv() implementations (e.g. the one in OpenBSD's stdlib)
segfault if we pass a NULL value. Only set environment variables if the
corresponding settings are defined to avoid this.
Note that this is a minor behaviour change as environment variables were
supposed to be set to an empty string if a setting was undefined. Given
that this feature isn't part of any official release yet, there's no
need to worry about backwards compatibility, really. Change the
documentation accordingly.
Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>
This isn't used anywhere and prevents the code from being compiled on
other platforms, such as *BSD.
Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>
The file name displayed in the rename hint should be escaped to avoid
XSS. Note that this vulnerability is only applicable when an attacker
has gained push access to the repository.
Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
The value stored to "t" during its initialization gets overwritten in
any case, so just leave it uninitialized. Spotted by clang-analyzer.
Signed-off-by: Lukas Fleischer <cgit@cryptocrack.de>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
This fixes a segfault for me with with -O2 optimization on x86
with gcc (Debian 4.4.5-8) 4.4.5
I can reliably reproduce it with the following parameters
when pointed to the git.git repository:
PATH_INFO='/git-core.git/diff/'
QUERY_STRING='id=2b93bfac0f5bcabbf60f174f4e7bfa9e318e64d5&id2=d6da71a9d16b8cf27f9d8f90692d3625c849cbc8'
Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Some tests would otherwise fail because commands such as
cd trash/repos/foo && git rev-list --reverse HEAD | head -1
would return 2 lines instead of 1: the 'cd' command also
prints the path when CDPATH is set.
Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
When looking for the modtime of a repo we used to rely on repo.defbranch
having a value. This is no longer true so this patch provides a default
value when needed.
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
For sites that do not want to configure mime types by hand but
still want the correct mime type for 'plain' blobs, configuring
a mime type file is made possible. This is handy since such a
file is normally already provided (at least on Linux systems).
Also, this reflects the gitweb option '$mimetypes_file'
Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
