On Sun, Aug 25, 2019 at 02:18:18PM +0900, Mike Hommey wrote:
> When add_note is called multiple times with the same key/value pair, the
> leaf_node it creates is leaked by notes_tree_insert.
Makes sense.
> diff --git a/notes.c b/notes.c
> index 75c028b300..ec35f5b551 100644
> --- a/notes.c
> +++ b/notes.c
> @@ -269,8 +269,10 @@ static int note_tree_insert(struct notes_tree *t, struct int_node *tree,
> case PTR_TYPE_NOTE:
> if (oideq(&l->key_oid, &entry->key_oid)) {
> /* skip concatenation if l == entry */
> - if (oideq(&l->val_oid, &entry->val_oid))
> + if (oideq(&l->val_oid, &entry->val_oid)) {
> + free(entry);
> return 0;
> + }
"entry" is passed in by the caller. Does anybody try to insert, and then
after the insertion continue to access the entry?
The only case I could find is this one in load_subtree():
if (note_tree_insert(t, node, n, l, type,
combine_notes_concatenate))
die("Failed to load %s %s into notes tree "
"from %s",
type == PTR_TYPE_NOTE ? "note" : "subtree",
oid_to_hex(&l->key_oid), t->ref);
If we fail to insert, we'll try to access the key_oid of the entry we
passed in, which might have been freed. But your patch is OK, because it
only touches a code path where we always return success.
Curiously, I think the existing case a few lines below your patch is
wrong, though:
ret = combine_notes(&l->val_oid,
&entry->val_oid);
if (!ret && is_null_oid(&l->val_oid))
note_tree_remove(t, tree, n, entry);
free(entry);
return ret;
If combining the notes fails, we'll free the entry and return an error
code, and then load_subtree() will access the freed memory. I think we
could just object_oid instead.
-Peff
