Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933228AbbDIIxY (ORCPT ); Thu, 9 Apr 2015 04:53:24 -0400 Received: from mail.kernel.org ([198.145.29.136]:41787 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755110AbbDIIxO (ORCPT ); Thu, 9 Apr 2015 04:53:14 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Nicholas Bellinger , "David S. Miller" , Zefan Li Subject: [PATCH 3.4 067/176] iscsi-target: Fail connection on short sendmsg writes Date: Thu, 9 Apr 2015 16:45:15 +0800 Message-Id: <1428569224-23820-67-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1428569028-23762-1-git-send-email-lizf@kernel.org> References: <1428569028-23762-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3043 Lines: 95 From: Nicholas Bellinger 3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit 6bf6ca7515c1df06f5c03737537f5e0eb191e29e upstream. This patch changes iscsit_do_tx_data() to fail on short writes when kernel_sendmsg() returns a value different than requested transfer length, returning -EPIPE and thus causing a connection reset to occur. This avoids a potential bug in the original code where a short write would result in kernel_sendmsg() being called again with the original iovec base + length. In practice this has not been an issue because iscsit_do_tx_data() is only used for transferring 48 byte headers + 4 byte digests, along with seldom used control payloads from NOPIN + TEXT_RSP + REJECT with less than 32k of data. So following Al's audit of iovec consumers, go ahead and fail the connection on short writes for now, and remove the bogus logic ahead of his proper upstream fix. Reported-by: Al Viro Cc: David S. Miller Signed-off-by: Nicholas Bellinger Signed-off-by: Zefan Li --- drivers/target/iscsi/iscsi_target_util.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index 4c05ed6..8d57ab3 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -1480,15 +1480,15 @@ static int iscsit_do_tx_data( struct iscsi_conn *conn, struct iscsi_data_count *count) { - int data = count->data_length, total_tx = 0, tx_loop = 0, iov_len; + int ret, iov_len; struct kvec *iov_p; struct msghdr msg; if (!conn || !conn->sock || !conn->conn_ops) return -1; - if (data <= 0) { - pr_err("Data length is: %d\n", data); + if (count->data_length <= 0) { + pr_err("Data length is: %d\n", count->data_length); return -1; } @@ -1497,20 +1497,16 @@ static int iscsit_do_tx_data( iov_p = count->iov; iov_len = count->iov_count; - while (total_tx < data) { - tx_loop = kernel_sendmsg(conn->sock, &msg, iov_p, iov_len, - (data - total_tx)); - if (tx_loop <= 0) { - pr_debug("tx_loop: %d total_tx %d\n", - tx_loop, total_tx); - return tx_loop; - } - total_tx += tx_loop; - pr_debug("tx_loop: %d, total_tx: %d, data: %d\n", - tx_loop, total_tx, data); + ret = kernel_sendmsg(conn->sock, &msg, iov_p, iov_len, + count->data_length); + if (ret != count->data_length) { + pr_err("Unexpected ret: %d send data %d\n", + ret, count->data_length); + return -EPIPE; } + pr_debug("ret: %d, sent data: %d\n", ret, count->data_length); - return total_tx; + return ret; } int rx_data( -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/