Prevent send-pack from segfaulting when a branch doesn't match

If `git push url foo` can't find a local branch named foo we can't
match it to any remote branch as the local branch is NULL and its
name is probably at position 0x34 in memory.  On most systems that
isn't a valid address for git-send-pack's virtual address space
and we segfault.

If we can't find a source match and we have no destination we
need to abort the match function early before we try to match the
destination against the remote.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/remote.c b/remote.c
index 2166a2bf15d20d5e51696fe3b56e4d66b0b12061..e7d735b98af231610c460c7aa34f12cdd6f37460 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -610,8 +610,11 @@ static int match_explicit(struct ref *src, struct ref *dst,
        if (!matched_src)
                errs = 1;
 
-       if (!dst_value)
+       if (!dst_value) {
+               if (!matched_src)
+                       return errs;
                dst_value = matched_src->name;
+       }
 
        switch (count_refspec_match(dst_value, dst, &matched_dst)) {
        case 1: