From 90499ad00ca59320b5bb43392b7931e1bd84cad2 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Wed, 25 Aug 2021 20:51:40 +0100
Subject: [PATCH] io_uring: add build check for buf_index overflows
Git-commit: 90499ad00ca59320b5bb43392b7931e1bd84cad2
Patch-mainline: v5.15-rc1
References: bsc#1205205
req->buf_index is u16 and so we rely on registered buffers indexes
fitting into it. Add a build check, so when the upper limit for the
number of buffers is lifted we get a compliation fail but not lurking
problems.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/787e8e1a17cea51ca6301426b1c4c4887b8bd676.1629920396.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 09194f7276ba..53326449d685 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10493,6 +10493,10 @@ static int __init io_uring_init(void)
sizeof(struct io_uring_rsrc_update));
BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
sizeof(struct io_uring_rsrc_update2));
+
+ /* ->buf_index is u16 */
+ BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
+
/* should fit into one byte */
BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
--
2.35.3