ospf: clean up some length checks.

[tcpdump] / print-ospf.c

diff --git a/print-ospf.c b/print-ospf.c
index 43f9dcc2e1b041fb19550bda68ac0bf4b78d823a..7d3578004c8946ffe5d9622ed9df1ba1a48d330e 100644 (file)
--- a/print-ospf.c
+++ b/print-ospf.c
@@ -301,7 +301,7 @@ ospf_te_lsa_print(netdissect_options *ndo,
 
         switch(tlv_type) {
         case LS_OPAQUE_TE_TLV_LINK:
-            while (tlv_length >= sizeof(subtlv_type) + sizeof(subtlv_length)) {
+            while (tlv_length != 0) {
                 if (tlv_length < 4) {
                     ND_PRINT("\n\t    Remaining TLV length %u < 4",
                            tlv_length);
@@ -322,6 +322,11 @@ ospf_te_lsa_print(netdissect_options *ndo,
                        subtlv_type,
                        subtlv_length);
 
+                if (tlv_length < subtlv_length) {
+                    ND_PRINT("\n\t    Remaining TLV length %u < %u",
+                           tlv_length + 4, subtlv_length + 4);
+                    return -1;
+                }
                 ND_TCHECK_LEN(tptr, subtlv_length);
                 switch(subtlv_type) {
                 case LS_OPAQUE_TE_LINK_SUBTLV_ADMIN_GROUP:
@@ -471,6 +476,11 @@ ospf_te_lsa_print(netdissect_options *ndo,
                 if (subtlv_length%4 != 0)
                     subtlv_length+=4-(subtlv_length%4);
 
+                if (tlv_length < subtlv_length) {
+                    ND_PRINT("\n\t    Remaining TLV length %u < %u",
+                           tlv_length + 4, subtlv_length + 4);
+                    return -1;
+                }
                 tlv_length-=subtlv_length;
                 tptr+=subtlv_length;
 
@@ -496,6 +506,11 @@ ospf_te_lsa_print(netdissect_options *ndo,
         /* in OSPF everything has to be 32-bit aligned, including TLVs */
         if (tlv_length%4 != 0)
             tlv_length+=4-(tlv_length%4);
+        if (tlv_length > ls_length) {
+            ND_PRINT("\n\t    Bogus padded length %u > %u", tlv_length,
+                   ls_length);
+            return -1;
+        }
         ls_length-=tlv_length;
         tptr+=tlv_length;
     }
@@ -806,25 +821,26 @@ ospf_print_lsa(netdissect_options *ndo,
             case LS_OPAQUE_TYPE_RI:
                tptr = (const uint8_t *)(lsap->lsa_un.un_ri_tlv);
 
-               while (ls_length != 0) {
+               int ls_length_remaining = ls_length;
+               while (ls_length_remaining != 0) {
                     ND_TCHECK_4(tptr);
-                   if (ls_length < 4) {
-                        ND_PRINT("\n\t    Remaining LS length %u < 4", ls_length);
+                   if (ls_length_remaining < 4) {
+                        ND_PRINT("\n\t    Remaining LS length %u < 4", ls_length_remaining);
                         return(ls_end);
                     }
                     tlv_type = GET_BE_U_2(tptr);
                     tlv_length = GET_BE_U_2(tptr + 2);
                     tptr+=4;
-                    ls_length-=4;
+                    ls_length_remaining-=4;
 
                     ND_PRINT("\n\t    %s TLV (%u), length: %u, value: ",
                            tok2str(lsa_opaque_ri_tlv_values,"unknown",tlv_type),
                            tlv_type,
                            tlv_length);
 
-                    if (tlv_length > ls_length) {
-                        ND_PRINT("\n\t    Bogus length %u > %u", tlv_length,
-                            ls_length);
+                    if (tlv_length > ls_length_remaining) {
+                        ND_PRINT("\n\t    Bogus length %u > remaining LS length %u", tlv_length,
+                            ls_length_remaining);
                         return(ls_end);
                     }
                     ND_TCHECK_LEN(tptr, tlv_length);
@@ -847,7 +863,7 @@ ospf_print_lsa(netdissect_options *ndo,
 
                     }
                     tptr+=tlv_length;
-                    ls_length-=tlv_length;
+                    ls_length_remaining-=tlv_length;
                 }
                 break;