[PATCH 2/3] show-branch: store resolved head in heap buffer
- From
Jeff King <peff@peff.net>
- Date
- Feb 14, 2017, 17:27 UTC
- Message-ID
- <20170214172745.4tnnu6kv7xru54vy@sigill.intra.peff.net>
- In-Reply-To
- <20170214172526.hzpm3d3ubd3vjnzr@sigill.intra.peff.net>
We resolve HEAD and copy the result to a fixed-size buffer with memcpy, never checking that it actually fits. This bug dates back to 8098a178b (Add git-symbolic-ref, 2005-09-30). Before that we used readlink(), which took a maximum buffer size.
We can fix this by using resolve_refdup(), which duplicates the buffer on the heap. That also lets us just check for a NULL pointer to see if we have resolved HEAD, and drop the extra head_p variable.
Signed-off-by: Jeff King <peff@peff.net> --- builtin/show-branch.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-)
diff --git a/builtin/show-branch.c b/builtin/show-branch.c index e4c488b8c..404c4d09a 100644 --- a/builtin/show-branch.c +++ b/builtin/show-branch.c @@ -473,8 +473,7 @@ static void snarf_refs(int head, int remotes) static int rev_is_head(char *head, char *name, unsigned char *head_sha1, unsigned char *sha1) { - if ((!head[0]) || - (head_sha1 && sha1 && hashcmp(head_sha1, sha1))) + if (!head || (head_sha1 && sha1 && hashcmp(head_sha1, sha1))) return 0; if (starts_with(head, "refs/heads/")) head += 11; @@ -620,8 +619,7 @@ int cmd_show_branch(int ac, const char **av, const char *prefix) int all_heads = 0, all_remotes = 0; int all_mask, all_revs; enum rev_sort_order sort_order = REV_SORT_IN_GRAPH_ORDER; - char head[128]; - const char *head_p; + char *head; struct object_id head_oid; int merge_base = 0; int independent = 0; @@ -786,17 +784,10 @@ int cmd_show_branch(int ac, const char **av, const char *prefix) snarf_refs(all_heads, all_remotes); } - head_p = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, - head_oid.hash, NULL); - if (head_p) { - size_t head_len = strlen(head_p); - memcpy(head, head_p, head_len + 1); - } - else { - head[0] = 0; - } + head = resolve_refdup("HEAD", RESOLVE_REF_READING, + head_oid.hash, NULL); - if (with_current_branch && head_p) { + if (with_current_branch && head) { int has_head = 0; for (i = 0; !has_head && i < ref_name_cnt; i++) { /* We are only interested in adding the branch
-- 2.12.0.rc1.479.g59880b11e