qla2xxx: Terminate exchange if corrupted

Corrupted ATIO is defined as length of fcp_header & fcp_cmd
payload is less than 0x38. It's the minimum size for a frame to
carry 8..16 bytes SCSI CDB. The exchange will be dropped or
terminated if corrupted.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[ bvanassche: Fixed spelling in patch title ]
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>

drivers/scsi/qla2xxx/qla_def.h

@@ -1556,7 +1556,8 @@ typedef struct {
 struct atio {
 	uint8_t		entry_type;		/* Entry type. */
 	uint8_t		entry_count;		/* Entry count. */
-	uint8_t		data[58];
+	__le16		attr_n_length;
+	uint8_t		data[56];
 	uint32_t	signature;
 #define ATIO_PROCESSED 0xDEADDEAD		/* Signature */
 };

drivers/scsi/qla2xxx/qla_target.c

@@ -6454,12 +6454,29 @@ qlt_24xx_process_atio_queue(struct scsi_qla_host *vha, uint8_t ha_locked)
 	if (!vha->flags.online)
 		return;
 
-	while (ha->tgt.atio_ring_ptr->signature != ATIO_PROCESSED) {
+	while ((ha->tgt.atio_ring_ptr->signature != ATIO_PROCESSED) ||
+	    fcpcmd_is_corrupted(ha->tgt.atio_ring_ptr)) {
 		pkt = (struct atio_from_isp *)ha->tgt.atio_ring_ptr;
 		cnt = pkt->u.raw.entry_count;
 
-		qlt_24xx_atio_pkt_all_vps(vha, (struct atio_from_isp *)pkt,
-		    ha_locked);
+		if (unlikely(fcpcmd_is_corrupted(ha->tgt.atio_ring_ptr))) {
+			/*
+			 * This packet is corrupted. The header + payload
+			 * can not be trusted. There is no point in passing
+			 * it further up.
+			 */
+			ql_log(ql_log_warn, vha, 0xffff,
+			    "corrupted fcp frame SID[%3phN] OXID[%04x] EXCG[%x] %64phN\n",
+			    pkt->u.isp24.fcp_hdr.s_id,
+			    be16_to_cpu(pkt->u.isp24.fcp_hdr.ox_id),
+			    le32_to_cpu(pkt->u.isp24.exchange_addr), pkt);
+
+			adjust_corrupted_atio(pkt);
+			qlt_send_term_exchange(vha, NULL, pkt, ha_locked, 0);
+		} else {
+			qlt_24xx_atio_pkt_all_vps(vha,
+			    (struct atio_from_isp *)pkt, ha_locked);
+		}
 
 		for (i = 0; i < cnt; i++) {
 			ha->tgt.atio_ring_index++;

drivers/scsi/qla2xxx/qla_target.h

@@ -427,13 +427,33 @@ struct atio_from_isp {
 		struct {
 			uint8_t  entry_type;	/* Entry type. */
 			uint8_t  entry_count;	/* Entry count. */
-			uint8_t  data[58];
+			__le16	 attr_n_length;
+#define FCP_CMD_LENGTH_MASK 0x0fff
+#define FCP_CMD_LENGTH_MIN  0x38
+			uint8_t  data[56];
 			uint32_t signature;
 #define ATIO_PROCESSED 0xDEADDEAD		/* Signature */
 		} raw;
 	} u;
 } __packed;
 
+static inline int fcpcmd_is_corrupted(struct atio *atio)
+{
+	if (atio->entry_type == ATIO_TYPE7 &&
+	    (le16_to_cpu(atio->attr_n_length & FCP_CMD_LENGTH_MASK) <
+	    FCP_CMD_LENGTH_MIN))
+		return 1;
+	else
+		return 0;
+}
+
+/* adjust corrupted atio so we won't trip over the same entry again. */
+static inline void adjust_corrupted_atio(struct atio_from_isp *atio)
+{
+	atio->u.raw.attr_n_length = cpu_to_le16(FCP_CMD_LENGTH_MIN);
+	atio->u.isp24.fcp_cmnd.add_cdb_len = 0;
+}
+
 #define CTIO_TYPE7 0x12 /* Continue target I/O entry (for 24xx) */
 
 /*