@matheusbsbs / matheus-bagliano / commits / d72cae12b9

get_sha1_with_context: always initialize oc->symlink_path

The get_sha1_with_context() function zeroes out the oc->symlink_path strbuf, but doesn't use strbuf_init() to set up the usual invariants (like pointing to the slopbuf). We don't actually write to the oc->symlink_path strbuf unless we call get_tree_entry_follow_symlinks(), and that function does initialize it. However, readers may still look at the zero'd strbuf. In practice this isn't a triggerable bug. The only caller that looks at it only does so when the mode we found is 0. This doesn't happen for non-tree-entries (where we return S_IFINVALID). A broken tree entry could have a mode of 0, but canon_mode() quietly rewrites that into S_IFGITLINK. So the "0" mode should only come up when we did indeed find a symlink. This is mostly just an accident of how the code happens to work, though. Let's future-proof ourselves to make sure the strbuf is properly initialized for all calls (it's only a few struct member assignments, not a heap allocation). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed May 19, 2017 at 08:52 UTC d72cae12b9a7bba3a6626e0b5805955eafdefcc6

2 files changed +1 -1

sha1_name.c

@@ -1511,6 +1511,7 @@ static int get_sha1_with_context_1(const char *name,

1511

1512 memset(oc, 0, sizeof(*oc));

1513 oc->mode = S_IFINVALID;

1514 + strbuf_init(&oc->symlink_path, 0);

1515 ret = get_sha1_1(name, namelen, sha1, flags);

1516 if (!ret)

1517 return ret;

tree-walk.c

-1

@@ -589,7 +589,6 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s

589 int i;

590

591 init_tree_desc(&t, NULL, 0UL);

592 - strbuf_init(result_path, 0);

592 strbuf_addstr(&namebuf, name);

593 hashcpy(current_tree_sha1, tree_sha1);

594