io_uring/rsrc: unify nospec indexing for direct descriptors

For file updates, the node reset isn't capping the value via
array_index_nospec() like the other paths do. Ensure it's all sane and
have the update path do the proper capping as well.

Reviewed-by: Gabriel Krisman Bertazi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: axboe

io_uring/rsrc.c

@@ -238,6 +238,9 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 			continue;
 
 		i = up->offset + done;
+		if (i >= ctx->file_table.data.nr)
+			break;
+		i = array_index_nospec(i, ctx->file_table.data.nr);
 		if (io_reset_rsrc_node(ctx, &ctx->file_table.data, i))
 			io_file_bitmap_clear(&ctx->file_table, i);
 

io_uring/rsrc.h

@@ -109,10 +109,15 @@ static inline void io_put_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node
 }
 
 static inline bool io_reset_rsrc_node(struct io_ring_ctx *ctx,
-				      struct io_rsrc_data *data, int index)
+				      struct io_rsrc_data *data,
+				      unsigned int index)
 {
-	struct io_rsrc_node *node = data->nodes[index];
+	struct io_rsrc_node *node;
 
+	if (index >= data->nr)
+		return false;
+	index = array_index_nospec(index, data->nr);
+	node = data->nodes[index];
 	if (!node)
 		return false;
 	io_put_rsrc_node(ctx, node);