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| author | Jeff King <peff@peff.net> | 2016-02-25 09:23:26 -0500 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2016-02-25 11:32:46 -0800 |
| commit | 13e0b0d3dc76353632dcb0bc63cdf03426154317 (patch) | |
| tree | a9ecffdfc2b839b81fc7b4d5aa1e543639a9cec3 | |
| parent | 47fe3f6ef0f5a336db90d816c5fb4330ffa23668 (diff) | |
| download | git-13e0b0d3dc76353632dcb0bc63cdf03426154317.tar.gz | |
use_pack: handle signed off_t overflow
A v2 pack index file can specify an offset within a packfile
of up to 2^64-1 bytes. On a system with a signed 64-bit
off_t, we can represent only up to 2^63-1. This means that a
corrupted .idx file can end up with a negative offset in the
pack code. Our bounds-checking use_pack function looks for
too-large offsets, but not for ones that have wrapped around
to negative. Let's do so, which fixes an out-of-bounds
access demonstrated in t5313.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | sha1_file.c | 2 | ||||
| -rwxr-xr-x | t/t5313-pack-bounds-checks.sh | 2 |
2 files changed, 3 insertions, 1 deletions
diff --git a/sha1_file.c b/sha1_file.c index bd0f8f7c8d..4a3a032d53 100644 --- a/sha1_file.c +++ b/sha1_file.c @@ -1041,6 +1041,8 @@ unsigned char *use_pack(struct packed_git *p, die("packfile %s cannot be accessed", p->pack_name); if (offset > (p->pack_size - 20)) die("offset beyond end of packfile (truncated pack?)"); + if (offset < 0) + die("offset before end of packfile (broken .idx?)"); if (!win || !in_window(win, offset)) { if (win) diff --git a/t/t5313-pack-bounds-checks.sh b/t/t5313-pack-bounds-checks.sh index 0717746479..a8a587abc3 100755 --- a/t/t5313-pack-bounds-checks.sh +++ b/t/t5313-pack-bounds-checks.sh @@ -136,7 +136,7 @@ test_expect_success 'bogus offset into v2 extended table' ' test_must_fail git index-pack --verify $pack ' -test_expect_failure 'bogus offset inside v2 extended table' ' +test_expect_success 'bogus offset inside v2 extended table' ' # We need two objects here, so we can plausibly require # an extended table (if the first object were larger than 2^31). do_pack "$object $(git rev-parse HEAD)" --index-version=2 && |