target: check XCOPY segment descriptor CSCD IDs

Ensure that the segment descriptor CSCD descriptor ID values correspond
to CSCD descriptor entries located in the XCOPY command parameter list.
SPC4r37 6.4.6.1 Table 150 specifies this range as 0000h to 07FFh, where
the CSCD descriptor location in the parameter list can be located via:
16 + (id * 32)
Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[ bvanassche: inserted "; " in the format string of an error message
  and also moved a "||" operator from the start of a line to the end
  of the previous line ]
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>

drivers/target/target_core_xcopy.c

@@ -278,6 +278,14 @@ static int target_xcopy_parse_segdesc_02(struct se_cmd *se_cmd, struct xcopy_op
 
 	xop->stdi = get_unaligned_be16(&desc[4]);
 	xop->dtdi = get_unaligned_be16(&desc[6]);
+
+	if (xop->stdi > XCOPY_CSCD_DESC_ID_LIST_OFF_MAX ||
+	    xop->dtdi > XCOPY_CSCD_DESC_ID_LIST_OFF_MAX) {
+		pr_err("XCOPY segment desc 0x02: unsupported CSCD ID > 0x%x; stdi: %hu dtdi: %hu\n",
+			XCOPY_CSCD_DESC_ID_LIST_OFF_MAX, xop->stdi, xop->dtdi);
+		return -EINVAL;
+	}
+
 	pr_debug("XCOPY seg desc 0x02: desc_len: %hu stdi: %hu dtdi: %hu, DC: %d\n",
 		desc_len, xop->stdi, xop->dtdi, dc);
 

drivers/target/target_core_xcopy.h

@@ -5,6 +5,12 @@
 #define XCOPY_NAA_IEEE_REGEX_LEN	16
 #define XCOPY_MAX_SECTORS		1024
 
+/*
+ * SPC4r37 6.4.6.1
+ * Table 150 — CSCD descriptor ID values
+ */
+#define XCOPY_CSCD_DESC_ID_LIST_OFF_MAX	0x07FF
+
 enum xcopy_origin_list {
 	XCOL_SOURCE_RECV_OP = 0x01,
 	XCOL_DEST_RECV_OP = 0x02,