player: don't set tag strings to NULL

bstr is a bounded string type, consisting of a pointer and a length
value. If the length is 0, the pointer can be NULL. This is somewhat
logical due to how this abstraction works, but it can leak when
converting to C strings.

talloc_strndup() returns NULL instead of "" in this case, which broke
some other code. Use bstrto0() instead, which is the "proper" function
to convert bstr to char*.

Fixes #1462.

1 files changed, 3 insertions, 3 deletions

diff --git a/common/tags.c b/common/tags.c
index bc9d98ea2f..92aaaad337 100644
--- a/common/tags.c
+++ b/common/tags.c
@@ -29,15 +29,15 @@ void mp_tags_set_bstr(struct mp_tags *tags, bstr key, bstr value)
     for (int n = 0; n < tags->num_keys; n++) {
         if (bstrcasecmp0(key, tags->keys[n]) == 0) {
             talloc_free(tags->values[n]);
-            tags->values[n] = talloc_strndup(tags, value.start, value.len);
+            tags->values[n] = bstrto0(tags, value);
             return;
         }
     }
 
     MP_RESIZE_ARRAY(tags, tags->keys,   tags->num_keys + 1);
     MP_RESIZE_ARRAY(tags, tags->values, tags->num_keys + 1);
-    tags->keys[tags->num_keys]   = talloc_strndup(tags, key.start,   key.len);
-    tags->values[tags->num_keys] = talloc_strndup(tags, value.start, value.len);
+    tags->keys[tags->num_keys]   = bstrto0(tags, key);
+    tags->values[tags->num_keys] = bstrto0(tags, value);
     tags->num_keys++;
 }