From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B569E5381 for ; Mon, 19 Jun 2023 10:45:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D1EBC433C0; Mon, 19 Jun 2023 10:45:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687171550; bh=bqPR8NIY00okH2KeJu7laBUha6vW9xHkuckTz/BhmxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aRZQe8HuGoP+p7v0/EHScup/jAhbujsh9gMGC/d6VF/0gYvZz6QPdaP48AQwe6ABU Q/axeUqJoE3qAF4BaVYbVPdVcD7zPm1GMk2j+eF5FUUpIl+A8V7FbYK+vdMlffYXGo yqxYnx4r6YrwcX4OMjsJJXtNwNTDCg0occJNgZI0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jens Axboe , Marek Majkowski Subject: [PATCH 6.1 054/166] io_uring/net: save msghdr->msg_control for retries Date: Mon, 19 Jun 2023 12:28:51 +0200 Message-ID: <20230619102157.372843953@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230619102154.568541872@linuxfoundation.org> References: <20230619102154.568541872@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jens Axboe commit cac9e4418f4cbd548ccb065b3adcafe073f7f7d2 upstream. If the application sets ->msg_control and we have to later retry this command, or if it got queued with IOSQE_ASYNC to begin with, then we need to retain the original msg_control value. This is due to the net stack overwriting this field with an in-kernel pointer, to copy it in. Hitting that path for the second time will now fail the copy from user, as it's attempting to copy from a non-user address. Cc: stable@vger.kernel.org # 5.10+ Link: https://github.com/axboe/liburing/issues/880 Reported-and-tested-by: Marek Majkowski Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/net.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/io_uring/net.c +++ b/io_uring/net.c @@ -65,6 +65,7 @@ struct io_sr_msg { u16 addr_len; u16 buf_group; void __user *addr; + void __user *msg_control; /* used only for send zerocopy */ struct io_kiocb *notif; }; @@ -182,11 +183,15 @@ static int io_sendmsg_copy_hdr(struct io struct io_async_msghdr *iomsg) { struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg); + int ret; iomsg->msg.msg_name = &iomsg->addr; iomsg->free_iov = iomsg->fast_iov; - return sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags, + ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags, &iomsg->free_iov); + /* save msg_control as sys_sendmsg() overwrites it */ + sr->msg_control = iomsg->msg.msg_control; + return ret; } int io_send_prep_async(struct io_kiocb *req) @@ -284,6 +289,7 @@ int io_sendmsg(struct io_kiocb *req, uns if (req_has_async_data(req)) { kmsg = req->async_data; + kmsg->msg.msg_control = sr->msg_control; } else { ret = io_sendmsg_copy_hdr(req, &iomsg); if (ret)