[SCSI] libfcoe: Check for order and missing critical descriptors for FIP ELS requests

As per FC-BB-5 rev.2, section 7.8.7.1, strict ordering of FIP descriptors
is required for ELS requests. Also, look for missing and duplicate critical
descriptors.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 28 insertions, 3 deletions

diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c
index ce651ca2a4bc..f009191063f1 100644
--- a/drivers/scsi/fcoe/libfcoe.c
+++ b/drivers/scsi/fcoe/libfcoe.c
@@ -871,7 +871,8 @@ static void fcoe_ctlr_recv_els(struct fcoe_ctlr *fip, struct sk_buff *skb)
         size_t els_len = 0;
         size_t rlen;
         size_t dlen;
-        u32 dupl_desc = 0;
+        u32 desc_mask = 0;
+        u32 desc_cnt = 0;
 
         fiph = (struct fip_header *)skb->data;
         sub = fiph->fip_subcode;
@@ -884,20 +885,27 @@ static void fcoe_ctlr_recv_els(struct fcoe_ctlr *fip, struct sk_buff *skb)
 
         desc = (struct fip_desc *)(fiph + 1);
         while (rlen > 0) {
+                desc_cnt++;
                 dlen = desc->fip_dlen * FIP_BPW;
                 if (dlen < sizeof(*desc) || dlen > rlen)
                         goto drop;
                 /* Drop ELS if there are duplicate critical descriptors */
                 if (desc->fip_dtype < 32) {
-                        if (dupl_desc & 1U << desc->fip_dtype) {
+                        if (desc_mask & 1U << desc->fip_dtype) {
                                 LIBFCOE_FIP_DBG(fip, "Duplicate Critical "
                                                 "Descriptors in FIP ELS\n");
                                 goto drop;
                         }
-                        dupl_desc |= (1 << desc->fip_dtype);
+                        desc_mask |= (1 << desc->fip_dtype);
                 }
                 switch (desc->fip_dtype) {
                 case FIP_DT_MAC:
+                        if (desc_cnt == 1) {
+                                LIBFCOE_FIP_DBG(fip, "FIP descriptors "
+                                                "received out of order\n");
+                                goto drop;
+                        }
+
                         if (dlen != sizeof(struct fip_mac_desc))
                                 goto len_err;
                         memcpy(granted_mac,
@@ -914,6 +922,11 @@ static void fcoe_ctlr_recv_els(struct fcoe_ctlr *fip, struct sk_buff *skb)
                 case FIP_DT_FDISC:
                 case FIP_DT_LOGO:
                 case FIP_DT_ELP:
+                        if (desc_cnt != 1) {
+                                LIBFCOE_FIP_DBG(fip, "FIP descriptors "
+                                                "received out of order\n");
+                                goto drop;
+                        }
                         if (fh)
                                 goto drop;
                         if (dlen < sizeof(*els) + sizeof(*fh) + 1)
@@ -929,6 +942,11 @@ static void fcoe_ctlr_recv_els(struct fcoe_ctlr *fip, struct sk_buff *skb)
                         /* standard says ignore unknown descriptors >= 128 */
                         if (desc->fip_dtype < FIP_DT_VENDOR_BASE)
                                 goto drop;
+                        if (desc_cnt <= 2) {
+                                LIBFCOE_FIP_DBG(fip, "FIP descriptors "
+                                                "received out of order\n");
+                                goto drop;
+                        }
                         break;
                 }
                 desc = (struct fip_desc *)((char *)desc + dlen);
@@ -944,6 +962,13 @@ static void fcoe_ctlr_recv_els(struct fcoe_ctlr *fip, struct sk_buff *skb)
             els_op == ELS_LS_ACC && is_valid_ether_addr(granted_mac))
                 fip->flogi_oxid = FC_XID_UNKNOWN;
 
+        if ((desc_cnt == 0) || ((els_op != ELS_LS_RJT) &&
+            (!(1U << FIP_DT_MAC & desc_mask)))) {
+                LIBFCOE_FIP_DBG(fip, "Missing critical descriptors "
+                                "in FIP ELS\n");
+                goto drop;
+        }
+
         /*
          * Convert skb into an fc_frame containing only the ELS.
          */