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| author | Edward Thomson <ethomson@github.com> | 2016-02-25 11:59:00 -0500 |
|---|---|---|
| committer | Edward Thomson <ethomson@github.com> | 2016-02-25 11:59:00 -0500 |
| commit | fd129f28f1c4662b9315a264f495c3ed7a9cfb50 (patch) | |
| tree | 7a86de68a528bbd09b1ecc2d8055f02b13dda6a4 | |
| parent | 9dfe11403a9a02ed056d7ea5621ba35b53012524 (diff) | |
| parent | 6d97beb91f413f4e90bab76fc7e05495bb0aab70 (diff) | |
| download | libgit2-fd129f28f1c4662b9315a264f495c3ed7a9cfb50.tar.gz | |
Merge pull request #3630 from libgit2/cmn/idx-extra-check
Extra checks for packfile indices
| -rw-r--r-- | src/pack.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/src/pack.c b/src/pack.c index 081e37084..52c652178 100644 --- a/src/pack.c +++ b/src/pack.c @@ -365,9 +365,14 @@ static unsigned char *pack_window_open( * pointless to ask for an offset into the middle of that * hash, and the pack_window_contains function above wouldn't match * don't allow an offset too close to the end of the file. + * + * Don't allow a negative offset, as that means we've wrapped + * around. */ if (offset > (p->mwf.size - 20)) return NULL; + if (offset < 0) + return NULL; return git_mwindow_open(&p->mwf, w_cursor, offset, 20, left); } @@ -1175,6 +1180,7 @@ int git_packfile_alloc(struct git_pack_file **pack_out, const char *path) static git_off_t nth_packed_object_offset(const struct git_pack_file *p, uint32_t n) { const unsigned char *index = p->index_map.data; + const unsigned char *end = index + p->index_map.len; index += 4 * 256; if (p->index_version == 1) { return ntohl(*((uint32_t *)(index + 24 * n))); @@ -1185,6 +1191,11 @@ static git_off_t nth_packed_object_offset(const struct git_pack_file *p, uint32_ if (!(off & 0x80000000)) return off; index += p->num_objects * 4 + (off & 0x7fffffff) * 8; + + /* Make sure we're not being sent out of bounds */ + if (index >= end - 8) + return -1; + return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) | ntohl(*((uint32_t *)(index + 4))); } @@ -1264,6 +1275,7 @@ static int pack_entry_find_offset( const unsigned char *index = p->index_map.data; unsigned hi, lo, stride; int pos, found = 0; + git_off_t offset; const unsigned char *current = 0; *offset_out = 0; @@ -1336,7 +1348,12 @@ static int pack_entry_find_offset( if (found > 1) return git_odb__error_ambiguous("found multiple offsets for pack entry"); - *offset_out = nth_packed_object_offset(p, pos); + if ((offset = nth_packed_object_offset(p, pos)) < 0) { + giterr_set(GITERR_ODB, "packfile index is corrupt"); + return -1; + } + + *offset_out = offset; git_oid_fromraw(found_oid, current); #ifdef INDEX_DEBUG_LOOKUP |