linux-kernel - [PATCH 5.16 0255/1017] io_uring: dont check unrelated req->open.how in accept request

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Message-Id: <20220405070401.832562237@linuxfoundation.org>
Date:   Tue,  5 Apr 2022 09:19:28 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.16 0255/1017] io_uring: dont check unrelated req->open.how in accept request

From: Jens Axboe <axboe@...nel.dk>

[ Upstream commit adf3a9e9f556613197583a1884f0de40a8bb6fb9 ]

Looks like a victim of too much copy/paste, we should not be looking
at req->open.how in accept. The point is to check CLOEXEC and error
out, which we don't invalid direct descriptors on exec. Hence any
attempt to get a direct descriptor with CLOEXEC is invalid.

No harm is done here, as req->open.how.flags overlaps with
req->accept.flags, but it's very confusing and might change if either of
those command structs are modified.

Fixes: aaa4db12ef7b ("io_uring: accept directly into fixed file table")
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/io_uring.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 783d7380331b..974f6fb327e7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5178,8 +5178,7 @@ static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	accept->nofile = rlimit(RLIMIT_NOFILE);
 
 	accept->file_slot = READ_ONCE(sqe->file_index);
-	if (accept->file_slot && ((req->open.how.flags & O_CLOEXEC) ||
-				  (accept->flags & SOCK_CLOEXEC)))
+	if (accept->file_slot && (accept->flags & SOCK_CLOEXEC))
 		return -EINVAL;
 	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
 		return -EINVAL;
-- 
2.34.1