blob: clear buf->head when freeing a buffer

Prevents accidental silent use-after-free bugs

Signed-off-by: Felix Fietkau <nbd@nbd.name>

blob.c

@@ -105,6 +105,7 @@ blob_buf_free(struct blob_buf *buf)
 {
 	free(buf->buf);
 	buf->buf = NULL;
+	buf->head = NULL;
 	buf->buflen = 0;
 }