From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946459Ab2I1Vws (ORCPT ); Fri, 28 Sep 2012 17:52:48 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:55300 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032066Ab2I1UXd (ORCPT ); Fri, 28 Sep 2012 16:23:33 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Roland Dreier , Christoph Hellwig , Boaz Harrosh , Nicholas Bellinger Subject: [ 039/218] target: Fix ->data_length re-assignment bug with SCSI overflow Date: Fri, 28 Sep 2012 13:14:16 -0700 Message-Id: <20120928201505.915758773@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.1.428.g652398a In-Reply-To: <20120928201501.208384923@linuxfoundation.org> References: <20120928201501.208384923@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Bellinger commit 4c054ba63ad47ef244cfcfa1cea38134620a5bae upstream. This patch fixes a long-standing bug with SCSI overflow handling where se_cmd->data_length was incorrectly being re-assigned to the larger CDB extracted allocation length, resulting in a number of fabric level errors that would end up causing a session reset in most cases. So instead now: - Only re-assign se_cmd->data_length durining UNDERFLOW (to use the smaller value) - Use existing se_cmd->data_length for OVERFLOW (to use the smaller value) This fix has been tested with the following CDB to generate an SCSI overflow: sg_raw -r512 /dev/sdc 28 0 0 0 0 0 0 0 9 0 Tested using iscsi-target, tcm_qla2xxx, loopback and tcm_vhost fabric ports. Here is a bit more detail on each case: - iscsi-target: Bug with open-iscsi with overflow, sg_raw returns -3584 bytes of data. - tcm_qla2xxx: Working as expected, returnins 512 bytes of data - loopback: sg_raw returns CHECK_CONDITION, from overflow rejection in transport_generic_map_mem_to_cmd() - tcm_vhost: Same as loopback Reported-by: Roland Dreier Cc: Roland Dreier Cc: Christoph Hellwig Cc: Boaz Harrosh Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/target_core_transport.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -3167,15 +3167,20 @@ static int transport_generic_cmd_sequenc /* Returns CHECK_CONDITION + INVALID_CDB_FIELD */ goto out_invalid_cdb_field; } - + /* + * For the overflow case keep the existing fabric provided + * ->data_length. Otherwise for the underflow case, reset + * ->data_length to the smaller SCSI expected data transfer + * length. + */ if (size > cmd->data_length) { cmd->se_cmd_flags |= SCF_OVERFLOW_BIT; cmd->residual_count = (size - cmd->data_length); } else { cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT; cmd->residual_count = (cmd->data_length - size); + cmd->data_length = size; } - cmd->data_length = size; } if (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB &&