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 (file)
--- 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);