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Merge pull request #3630 from libgit2/cmn/idx-extra-check

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Extra checks for packfile indices
This commit is contained in:
Edward Thomson 2016-02-25 11:59:00 -05:00
commit fd129f28f1
1 changed files with 18 additions and 1 deletions
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19
src/pack.c
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@ -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