[PATCH 06/23] remote.c: make match_refs() copy src ref before assigning to peer_ref
- From
Jay Soffian <jaysoffian@gmail.com>
- Date
- Feb 24, 2009, 09:50 UTC
- Message-ID
- <9bcec2dfd965836ae4a34385f4db7e7b42d313a5.1235467368.git.jaysoffian@gmail.com>
- In-Reply-To
- <cover.1235467368.git.jaysoffian@gmail.com>
In some instances, match_refs() sets the peer_ref field of refs in the dst list such that it points to a ref in the src list. This prevents callers from freeing both the src and dst lists, as doing so would cause a double-free since free_refs() frees the peer_ref.
As well, the following configuration causes two refs in the dst list to have the same peer_ref, which can also lead to a double-free:
push = refs/heads/master:refs/heads/backup push = refs/heads/master:refs/heads/master
Existing callers of match_heads() call it only once and then terminate, w/o ever bothering to free the src or dst lists, so this is not currently a problem.
This patch modifies match_refs() to first copy any refs it plucks from the src list before assigning them as a peer_ref, thus future-proofing the function against callers who might wish to free the src and/or dst lists.
Signed-off-by: Jay Soffian <jaysoffian@gmail.com> --- remote.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/remote.c b/remote.c index 6385a22..64879ce 100644 --- a/remote.c +++ b/remote.c @@ -927,6 +927,7 @@ static int match_explicit(struct ref *src, struct ref *dst, struct refspec *rs) { struct ref *matched_src, *matched_dst; + int copy_src; const char *dst_value = rs->dst; char *dst_guess; @@ -937,6 +938,7 @@ static int match_explicit(struct ref *src, struct ref *dst, matched_src = matched_dst = NULL; switch (count_refspec_match(rs->src, src, &matched_src)) { case 1: + copy_src = 1; break; case 0: /* The source could be in the get_sha1() format @@ -946,6 +948,7 @@ static int match_explicit(struct ref *src, struct ref *dst, matched_src = try_explicit_object_name(rs->src); if (!matched_src) return error("src refspec %s does not match any.", rs->src); + copy_src = 0; break; default: return error("src refspec %s matches more than one.", rs->src); @@ -991,7 +994,7 @@ static int match_explicit(struct ref *src, struct ref *dst, return error("dst ref %s receives from more than one src.", matched_dst->name); else { - matched_dst->peer_ref = matched_src; + matched_dst->peer_ref = copy_src ? copy_ref(matched_src) : matched_src; matched_dst->force = rs->force; } return 0; @@ -1099,7 +1102,7 @@ int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail, dst_peer = make_linked_ref(dst_name, dst_tail); hashcpy(dst_peer->new_sha1, src->new_sha1); } - dst_peer->peer_ref = src; + dst_peer->peer_ref = copy_ref(src); dst_peer->force = pat->force; free_name: free(dst_name);
-- 1.6.2.rc1.291.g83eb