load_subtree(): check that prefix_len is in the expected range

This value, which is stashed in the last byte of an object_id hash,
gets handed around a lot. So add a sanity check before using it in
`load_subtree()`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Michael Haggerty 2017-09-08 18:10:10 +02:00 committed by Junio C Hamano
parent 06cfa75675
commit 3964281524

View file

@ -417,7 +417,10 @@ static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
oid_to_hex(&subtree->val_oid));
prefix_len = subtree->key_oid.hash[KEY_INDEX];
assert(prefix_len * 2 >= n);
if (prefix_len >= GIT_SHA1_RAWSZ)
BUG("prefix_len (%"PRIuMAX") is out of range", (uintmax_t)prefix_len);
if (prefix_len * 2 < n)
BUG("prefix_len (%"PRIuMAX") is too small", (uintmax_t)prefix_len);
memcpy(object_oid.hash, subtree->key_oid.hash, prefix_len);
while (tree_entry(&desc, &entry)) {
unsigned char type;