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parse_commit_buffer: tighten checks while parsing

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This tightens the parsing of a commit object in a couple of ways.

 - The "tree " header must end with a LF (earlier we did not
   check this condition).

 - Make sure parsing of timestamp on the "committer " header
   does not go beyond the buffer, even when (1) the "author "
   header does not end with a LF (this means that the commit
   object is malformed and lacks the committer information) or
   (2) the "committer " header does not have ">" that is the end
   of the e-mail address, or (3) the "committer " header does
   not end with a LF.

We however still keep the existing behaviour to return a parsed
commit object even when non-structural headers such as committer
and author are malformed, so that tools that need to look at
commits to clean up a history with such broken commits can still
get at the structural data (i.e. the parents chain and the tree
object).

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Martin Koegler 2008-01-19 18:35:23 +01:00 committed by Junio C Hamano
parent a3b811a491
commit 0a61779994
1 changed files with 20 additions and 7 deletions
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27
commit.c
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@ -48,19 +48,32 @@ struct commit *lookup_commit(const unsigned char *sha1)
return check_commit(obj, sha1, 0);
}
static unsigned long parse_commit_date(const char *buf)
static unsigned long parse_commit_date(const char *buf, const char *tail)
{
unsigned long date;
const char *dateptr;
if (buf + 6 >= tail)
return 0;
if (memcmp(buf, "author", 6))
return 0;
while (*buf++ != '\n')
while (buf < tail && *buf++ != '\n')
/* nada */;
if (buf + 9 >= tail)
return 0;
if (memcmp(buf, "committer", 9))
return 0;
while (*buf++ != '>')
while (buf < tail && *buf++ != '>')
/* nada */;
date = strtoul(buf, NULL, 10);
if (buf >= tail)
return 0;
dateptr = buf;
while (buf < tail && *buf++ != '\n')
/* nada */;
if (buf >= tail)
return 0;
/* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
date = strtoul(dateptr, NULL, 10);
if (date == ULONG_MAX)
date = 0;
return date;
@ -236,9 +249,9 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
return 0;
item->object.parsed = 1;
tail += size;
if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
if (get_sha1_hex(bufptr + 5, parent) < 0)
return error("bad tree pointer in commit %s",
sha1_to_hex(item->object.sha1));
item->tree = lookup_tree(parent);
@ -275,7 +288,7 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
n_refs++;
}
}
item->date = parse_commit_date(bufptr);
item->date = parse_commit_date(bufptr, tail);
if (track_object_refs) {
unsigned i = 0;