Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 5.4 086/152] io_uring: fix 32-bit compatability with sendmsg/recvmsg
Date:   Tue,  3 Mar 2020 18:43:04 +0100
Message-Id: <20200303174312.327597911@linuxfoundation.org>
In-Reply-To: <20200303174302.523080016@linuxfoundation.org>
References: <20200303174302.523080016@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Jens Axboe <axboe@kernel.dk>

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>

---
 fs/io_uring.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1657,6 +1657,11 @@ static int io_send_recvmsg(struct io_kio
 		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);