target: report too-small parameter lists everywhere

Several places were not checking that the parameter list length
was large enough, and thus accessing invalid memory.  Zero-length
parameter lists are just a special case of this.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_alua.c

@@ -218,6 +218,13 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 		return -EINVAL;
 	}
+	if (cmd->data_length < 4) {
+		pr_warn("SET TARGET PORT GROUPS parameter list length %u too"
+			" small\n", cmd->data_length);
+		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+		return -EINVAL;
+	}
+
 	buf = transport_kmap_data_sg(cmd);
 
 	/*

drivers/target/target_core_iblock.c

@@ -325,17 +325,30 @@ static int iblock_execute_unmap(struct se_cmd *cmd)
 	struct iblock_dev *ibd = dev->dev_ptr;
 	unsigned char *buf, *ptr = NULL;
 	sector_t lba;
-	int size = cmd->data_length;
+	int size;
 	u32 range;
 	int ret = 0;
 	int dl, bd_dl;
 
+	if (cmd->data_length < 8) {
+		pr_warn("UNMAP parameter list length %u too small\n",
+			cmd->data_length);
+		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+		return -EINVAL;
+	}
+
 	buf = transport_kmap_data_sg(cmd);
 
 	dl = get_unaligned_be16(&buf[0]);
 	bd_dl = get_unaligned_be16(&buf[2]);
 
-	size = min(size - 8, bd_dl);
+	size = cmd->data_length - 8;
+	if (bd_dl > size)
+		pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
+			cmd->data_length, bd_dl);
+	else
+		size = bd_dl;
+
 	if (size / 16 > dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count) {
 		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 		ret = -EINVAL;

drivers/target/target_core_pr.c

@@ -1540,6 +1540,14 @@ static int core_scsi3_decode_spec_i_port(
 	tidh_new->dest_local_nexus = 1;
 	list_add_tail(&tidh_new->dest_list, &tid_dest_list);
 
+	if (cmd->data_length < 28) {
+		pr_warn("SPC-PR: Received PR OUT parameter list"
+			" length too small: %u\n", cmd->data_length);
+		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+		ret = -EINVAL;
+		goto out;
+	}
+
 	buf = transport_kmap_data_sg(cmd);
 	/*
 	 * For a PERSISTENT RESERVE OUT specify initiator ports payload,