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parse_commit_buffer: tighten checks while parsing

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>

Martin Koegler committed Jan 19, 2008 at 18:35 UTC 0a61779994aa3de41d57bb85bd88a2f56c7ba7d8

1 file changed +20 -7

commit.c

+20 -7

@@ -48,19 +48,32 @@ struct commit *lookup_commit(const unsigned char *sha1)

48 return check_commit(obj, sha1, 0);

49 }

51 -static unsigned long parse_commit_date(const char *buf)

51 +static unsigned long parse_commit_date(const char *buf, const char *tail)

52 {

53 unsigned long date;

54 + const char *dateptr;

56 + if (buf + 6 >= tail)

57 + return 0;

58 if (memcmp(buf, "author", 6))

59 return 0;

57 - while (*buf++ != '\n')

60 + while (buf < tail && *buf++ != '\n')

61 /* nada */;

62 + if (buf + 9 >= tail)

63 + return 0;

64 if (memcmp(buf, "committer", 9))

65 return 0;

61 - while (*buf++ != '>')

66 + while (buf < tail && *buf++ != '>')

67 /* nada */;

63 - date = strtoul(buf, NULL, 10);

68 + if (buf >= tail)

69 + return 0;

70 + dateptr = buf;

71 + while (buf < tail && *buf++ != '\n')

72 + /* nada */;

73 + if (buf >= tail)

74 + return 0;

75 + /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */

76 + date = strtoul(dateptr, NULL, 10);

77 if (date == ULONG_MAX)

78 date = 0;

79 return date;

@@ -236,9 +249,9 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)

249 return 0;

250 item->object.parsed = 1;

251 tail += size;

239 - if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))

252 + if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')

253 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));

241 - if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)

254 + if (get_sha1_hex(bufptr + 5, parent) < 0)

255 return error("bad tree pointer in commit %s",

256 sha1_to_hex(item->object.sha1));

257 item->tree = lookup_tree(parent);

@@ -275,7 +288,7 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)

288 n_refs++;

289 }

290 }

278 - item->date = parse_commit_date(bufptr);

291 + item->date = parse_commit_date(bufptr, tail);

292

293 if (track_object_refs) {

294 unsigned i = 0;