From 0f69a38737538c8a265f75d26996818f98c899e4 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Thu, 13 Aug 2015 21:59:19 -0700 Subject: [PATCH] target: Fix handling of small allocation lengths in REPORT LUNS REPORT LUNS should not fail just because the allocation length is less than 16. The relevant section of SPC-4 is: 4.2.5.6 Allocation length The ALLOCATION LENGTH field specifies the maximum number of bytes or blocks that an application client has allocated in the Data-In Buffer. The ALLOCATION LENGTH field specifies bytes unless a different requirement is stated in the command definition. An allocation length of zero specifies that no data shall be transferred. This condition shall not be considered an error. So we should just truncate our response rather than return an error. Signed-off-by: Roland Dreier Signed-off-by: Spencer Baugh Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_spc.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index 556ea1b2cdd8..f87d4cef6d39 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -1203,17 +1203,13 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd) struct se_dev_entry *deve; struct se_session *sess = cmd->se_sess; struct se_node_acl *nacl; + struct scsi_lun slun; unsigned char *buf; u32 lun_count = 0, offset = 8; - - if (cmd->data_length < 16) { - pr_warn("REPORT LUNS allocation length %u too small\n", - cmd->data_length); - return TCM_INVALID_CDB_FIELD; - } + __be32 len; buf = transport_kmap_data_sg(cmd); - if (!buf) + if (cmd->data_length && !buf) return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; /* @@ -1234,10 +1230,12 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd) * See SPC2-R20 7.19. */ lun_count++; - if ((offset + 8) > cmd->data_length) + if (offset >= cmd->data_length) continue; - int_to_scsilun(deve->mapped_lun, (struct scsi_lun *)&buf[offset]); + int_to_scsilun(deve->mapped_lun, &slun); + memcpy(buf + offset, &slun, + min(8u, cmd->data_length - offset)); offset += 8; } rcu_read_unlock(); @@ -1250,16 +1248,18 @@ done: * If no LUNs are accessible, report virtual LUN 0. */ if (lun_count == 0) { - int_to_scsilun(0, (struct scsi_lun *)&buf[offset]); + int_to_scsilun(0, &slun); + if (cmd->data_length > 8) + memcpy(buf + offset, &slun, + min(8u, cmd->data_length - offset)); lun_count = 1; } - lun_count *= 8; - buf[0] = ((lun_count >> 24) & 0xff); - buf[1] = ((lun_count >> 16) & 0xff); - buf[2] = ((lun_count >> 8) & 0xff); - buf[3] = (lun_count & 0xff); - transport_kunmap_data_sg(cmd); + if (buf) { + len = cpu_to_be32(lun_count * 8); + memcpy(buf, &len, min_t(int, sizeof len, cmd->data_length)); + transport_kunmap_data_sg(cmd); + } target_complete_cmd_with_length(cmd, GOOD, 8 + lun_count * 8); return 0;