[lkml]   [2019]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] io_uring: fix SQPOLL cpu check
The array_index_nospec() check in io_sq_offload_start() is performed
before any checks on p->sq_thread_cpu are done. This means cpu is
clamped and therefore no error occurs when out-of-range values are
passed in from userspace. This is in violation of the specification
for io_ring_setup() and causes the io_ring_setup unit test in liburing
to regress.

Add a new bounds check on sq_thread_cpu at the start of
io_sq_offload_start() so we can exit the function early when bad
values are passed in.

Fixes: 975554b03edd ("io_uring: fix SQPOLL cpu validation")
Signed-off-by: Stephen Bates <>
fs/io_uring.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 30a5687..e458470 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2316,6 +2316,9 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
int ret;

+ if (p->sq_thread_cpu >= nr_cpu_ids)
+ return -EINVAL;
ctx->sqo_mm = current->mm;
 \ /
  Last update: 2019-06-12 01:56    [W:2.062 / U:6.560 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site