From 0a61779994aa3de41d57bb85bd88a2f56c7ba7d8 Mon Sep 17 00:00:00 2001 From: Martin Koegler Date: Sat, 19 Jan 2008 18:35:23 +0100 Subject: [PATCH] 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 Signed-off-by: Junio C Hamano --- commit.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/commit.c b/commit.c index f074811edc..8b8fb04d1f 100644 --- a/commit.c +++ b/commit.c @@ -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;