[PATCH 5.17 112/219] io_uring: verify pad field is 0 in io_get_ext_arg

[Greg Kroah-Hartman]

From: Dylan Yudaken <dylany@xxxxxx>

[ Upstream commit d2347b9695dafe5c388a5f9aeb70e27a7a4d29cf ]

Ensure that only 0 is passed for pad here.

Fixes: c73ebb685fb6 ("io_uring: add timeout support for io_uring_enter()")
Signed-off-by: Dylan Yudaken <dylany@xxxxxx>
Link: https://lore.kernel.org/r/20220412163042.2788062-5-dylany@xxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/io_uring.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2838bc6cdbc8..7a652c8eeed2 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10109,6 +10109,8 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
 		return -EINVAL;
 	if (copy_from_user(&arg, argp, sizeof(arg)))
 		return -EFAULT;
+	if (arg.pad)
+		return -EINVAL;
 	*sig = u64_to_user_ptr(arg.sigmask);
 	*argsz = arg.sigmask_sz;
 	*ts = u64_to_user_ptr(arg.ts);
-- 
2.35.1