connection: Handle non-nullable strings in wl_connection_demarshal

Currently a null string passed into a non-nullable argument of a message
will decode succesfully, probably resulting in the handler function
crashing. Instead treat it the same way we do non-nullable objects and ids.

Signed-off-by: Fergus Dall <sidereal@google.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/connection.c b/src/connection.c
index 69190a1..ccbb972 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -749,6 +749,13 @@ wl_connection_demarshal(struct wl_connection *connection,
 		case 's':
 			length = *p++;
 
+			if (length == 0 && !arg.nullable) {
+				wl_log("NULL string received on non-nullable "
+				       "type, message %s(%s)\n", message->name,
+				       message->signature);
+				errno = EINVAL;
+				goto err;
+			}
 			if (length == 0) {
 				closure->args[i].s = NULL;
 				break;