This is a note to let you know that I've just added the patch titled target: Re-add check to reject control WRITEs with overflow data to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: target-re-add-check-to-reject-control-writes-with-overflow-data.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4ff83daa0200affe1894bd33d17bac404e3d78d4 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Date: Thu, 11 May 2017 01:07:24 -0700 Subject: target: Re-add check to reject control WRITEs with overflow data From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> commit 4ff83daa0200affe1894bd33d17bac404e3d78d4 upstream. During v4.3 when the overflow/underflow check was relaxed by commit c72c525022: commit c72c5250224d475614a00c1d7e54a67f77cd3410 Author: Roland Dreier <roland@xxxxxxxxxxxxxxx> Date: Wed Jul 22 15:08:18 2015 -0700 target: allow underflow/overflow for PR OUT etc. commands to allow underflow/overflow for Windows compliance + FCP, a consequence was to allow control CDBs to process overflow data for iscsi-target with immediate data as well. As per Roland's original change, continue to allow underflow cases for control CDBs to make Windows compliance + FCP happy, but until overflow for control CDBs is supported tree-wide, explicitly reject all control WRITEs with overflow following pre v4.3.y logic. Reported-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Cc: Roland Dreier <roland@xxxxxxxxxxxxxxx> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/target/target_core_transport.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1182,15 +1182,28 @@ target_cmd_size_check(struct se_cmd *cmd if (cmd->unknown_data_length) { cmd->data_length = size; } else if (size != cmd->data_length) { - pr_warn("TARGET_CORE[%s]: Expected Transfer Length:" + pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:" " %u does not match SCSI CDB Length: %u for SAM Opcode:" " 0x%02x\n", cmd->se_tfo->get_fabric_name(), cmd->data_length, size, cmd->t_task_cdb[0]); - if (cmd->data_direction == DMA_TO_DEVICE && - cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) { - pr_err("Rejecting underflow/overflow WRITE data\n"); - return TCM_INVALID_CDB_FIELD; + if (cmd->data_direction == DMA_TO_DEVICE) { + if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) { + pr_err_ratelimited("Rejecting underflow/overflow" + " for WRITE data CDB\n"); + return TCM_INVALID_CDB_FIELD; + } + /* + * Some fabric drivers like iscsi-target still expect to + * always reject overflow writes. Reject this case until + * full fabric driver level support for overflow writes + * is introduced tree-wide. + */ + if (size > cmd->data_length) { + pr_err_ratelimited("Rejecting overflow for" + " WRITE control CDB\n"); + return TCM_INVALID_CDB_FIELD; + } } /* * Reject READ_* or WRITE_* with overflow/underflow for Patches currently in stable-queue which might be from nab@xxxxxxxxxxxxxxx are queue-4.9/target-re-add-check-to-reject-control-writes-with-overflow-data.patch