From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 27 Feb 2020 21:17:49 +0000 (-0700)
Subject: io_uring: fix 32-bit compatability with sendmsg/recvmsg
X-Git-Tag: v5.4.24~67
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7eaf718b83ffbec852c8485a4c433f14621cf9b5;p=platform%2Fkernel%2Flinux-rpi.git

io_uring: fix 32-bit compatability with sendmsg/recvmsg

commit d876836204897b6d7d911f942084f69a1e9d5c4d upstream.

We must set MSG_CMSG_COMPAT if we're in compatability mode, otherwise
the iovec import for these commands will not do the right thing and fail
the command with -EINVAL.

Found by running the test suite compiled as 32-bit.

Cc: stable@vger.kernel.org
Fixes: aa1fa28fc73e ("io_uring: add support for recvmsg()")
Fixes: 0fa03c624d8f ("io_uring: add support for sendmsg()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f34a8f7..e37b841 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1657,6 +1657,11 @@ static int io_send_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		else if (force_nonblock)
 			flags |= MSG_DONTWAIT;
 
+#ifdef CONFIG_COMPAT
+		if (req->ctx->compat)
+			flags |= MSG_CMSG_COMPAT;
+#endif
+
 		msg = (struct user_msghdr __user *) (unsigned long)
 			READ_ONCE(sqe->addr);