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author | Jim Meyering <jim@meyering.net> | 2007-07-03 14:40:20 +0400 |
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committer | Junio C Hamano <gitster@pobox.com> | 2007-07-03 23:25:29 +0400 |
commit | 9cb18f56fdee6885884f5f08bd5335a42d9034dc (patch) | |
tree | 9af06f4ef04c75a07edeb652255c63b084831e91 /quote.h | |
parent | e8964a5b91e13169ad73c7b1db2e904441ad93f5 (diff) |
Don't smash stack when $GIT_ALTERNATE_OBJECT_DIRECTORIES is too long
There is no restriction on the length of the name returned by
get_object_directory, other than the fact that it must be a stat'able
git object directory. That means its name may have length up to
PATH_MAX-1 (i.e., often 4095) not counting the trailing NUL.
Combine that with the assumption that the concatenation of that name and
suffixes like "/info/alternates" and "/pack/---long-name---.idx" will fit
in a buffer of length PATH_MAX, and you see the problem. Here's a fix:
sha1_file.c (prepare_packed_git_one): Lengthen "path" buffer
so we are guaranteed to be able to append "/pack/" without checking.
Skip any directory entry that is too long to be appended.
(read_info_alternates): Protect against a similar buffer overrun.
Before this change, using the following admittedly contrived environment
setting would cause many git commands to clobber their stack and segfault
on a system with PATH_MAX == 4096:
t=$(perl -e '$s=".git/objects";$n=(4096-6-length($s))/2;print "./"x$n . $s')
export GIT_ALTERNATE_OBJECT_DIRECTORIES=$t
touch g
./git-update-index --add g
If you run the above commands, you'll soon notice that many
git commands now segfault, so you'll want to do this:
unset GIT_ALTERNATE_OBJECT_DIRECTORIES
Signed-off-by: Jim Meyering <jim@meyering.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'quote.h')
0 files changed, 0 insertions, 0 deletions