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authorNicholas Bellinger <nab@linux-iscsi.org>2012-08-16 15:33:10 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-02 09:47:23 -0700
commite3653afefd005d16274c9f16511530de3d511c1a (patch)
tree958c2b6ef67db1df544b65c5652cc23096a38bf6 /drivers/target
parent047b8d01518246de438ba76a957889b6e661638e (diff)
target: Fix ->data_length re-assignment bug with SCSI overflow
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 <roland@purestorage.com> Cc: Roland Dreier <roland@purestorage.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_transport.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index d3a7342317ea..910c8b0cd731 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -3672,15 +3672,20 @@ static int transport_generic_cmd_sequencer(
/* 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;
}
transport_set_supported_SAM_opcode(cmd);