From: Victor Julien <victor@inliniac.net>
Date: Mon, 16 May 2016 12:11:56 +0000 (+0200)
Subject: ipv6: simplify ext hdr parsing
X-Git-Tag: suricata-3.1RC1~133
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b77d30727235e9195e581dfc15fca05a2dac9be6;p=thirdparty%2Fsuricata.git

ipv6: simplify ext hdr parsing
---

diff --git a/src/decode-ipv6.c b/src/decode-ipv6.c
index 9ca0630652..ac0ad752ba 100644
--- a/src/decode-ipv6.c
+++ b/src/decode-ipv6.c
@@ -106,7 +106,7 @@ static inline
 #endif
 void DecodeIPV6FragHeader(Packet *p, uint8_t *pkt,
                           uint16_t hdrextlen, uint16_t plen,
-                          uint16_t ip6_exthdrs_cnt, IPV6GenOptHdr *ip6_exthdrs)
+                          uint16_t prev_hdrextlen)
 {
     uint16_t frag_offset = (*(pkt + 2) << 8 | *(pkt + 3)) & 0xFFF8;
     int frag_morefrags   = (*(pkt + 2) << 8 | *(pkt + 3)) & 0x0001;
@@ -135,8 +135,8 @@ void DecodeIPV6FragHeader(Packet *p, uint8_t *pkt,
     p->ip6eh.fh_data_len = data_len;
 
     /* if we have a prev hdr, store the type and offset of it */
-    if (ip6_exthdrs_cnt > 1) {
-        p->ip6eh.fh_prev_hdr_offset = frag_hdr_offset - ip6_exthdrs[ip6_exthdrs_cnt - 1].len;
+    if (prev_hdrextlen) {
+        p->ip6eh.fh_prev_hdr_offset = frag_hdr_offset - prev_hdrextlen;
     }
 
     SCLogDebug("IPV6 FH: frag_hdr_offset %u, data_offset %u, data_len %u",
@@ -151,14 +151,10 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
 
     uint8_t *orig_pkt = pkt;
     uint8_t nh = 0; /* careful, 0 is actually a real type */
-    uint16_t hdrextlen;
+    uint16_t hdrextlen = 0;
     uint16_t plen;
     char dstopts = 0;
     char exthdr_fh_done = 0;
-
-    uint8_t ip6_exthdrs_cnt = 0;
-    IPV6GenOptHdr ip6_exthdrs[IPV6_MAX_OPT];
-
     int hh = 0;
     int rh = 0;
     int eh = 0;
@@ -212,15 +208,6 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                     SCReturn;
                 }
 
-                if (ip6_exthdrs_cnt < IPV6_MAX_OPT)
-                {
-                    ip6_exthdrs[ip6_exthdrs_cnt].type = nh;
-                    ip6_exthdrs[ip6_exthdrs_cnt].next = *pkt;
-                    ip6_exthdrs[ip6_exthdrs_cnt].len = hdrextlen;
-                    ip6_exthdrs[ip6_exthdrs_cnt].data = pkt+2;
-                    ip6_exthdrs_cnt++;
-                }
-
                 if (rh) {
                     ENGINE_SET_EVENT(p, IPV6_EXTHDR_DUPL_RH);
                     /* skip past this extension so we can continue parsing the rest
@@ -260,15 +247,6 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                     SCReturn;
                 }
 
-                if (ip6_exthdrs_cnt < IPV6_MAX_OPT)
-                {
-                    ip6_exthdrs[ip6_exthdrs_cnt].type = nh;
-                    ip6_exthdrs[ip6_exthdrs_cnt].next = *pkt;
-                    ip6_exthdrs[ip6_exthdrs_cnt].len = hdrextlen;
-                    ip6_exthdrs[ip6_exthdrs_cnt].data = pkt+2;
-                    ip6_exthdrs_cnt++;
-                }
-
                 uint8_t *ptr = pkt + 2; /* +2 to go past nxthdr and len */
 
                 /* point the pointers to right structures
@@ -431,6 +409,7 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
             }
 
             case IPPROTO_FRAGMENT:
+            {
                 IPV6_SET_L4PROTO(p,nh);
                 /* store the offset of this extension into the packet
                  * past the ipv6 header. We use it in defrag for creating
@@ -440,6 +419,7 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                     exthdr_fh_done = 1;
                 }
 
+                uint16_t prev_hdrextlen = hdrextlen;
                 hdrextlen = sizeof(IPV6FragHdr);
                 if (hdrextlen > plen) {
                     ENGINE_SET_EVENT(p, IPV6_TRUNC_EXTHDR);
@@ -452,15 +432,6 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                     /* non fatal, lets try to continue */
                 }
 
-                if(ip6_exthdrs_cnt<IPV6_MAX_OPT)
-                {
-                    ip6_exthdrs[ip6_exthdrs_cnt].type = nh;
-                    ip6_exthdrs[ip6_exthdrs_cnt].next = *pkt;
-                    ip6_exthdrs[ip6_exthdrs_cnt].len = hdrextlen;
-                    ip6_exthdrs[ip6_exthdrs_cnt].data = pkt+2;
-                    ip6_exthdrs_cnt++;
-                }
-
                 if (IPV6_EXTHDR_ISSET_FH(p)) {
                     ENGINE_SET_EVENT(p, IPV6_EXTHDR_DUPL_FH);
                     nh = *pkt;
@@ -473,8 +444,7 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                 IPV6_EXTHDR_SET_FH(p);
 
                 /* parse the header and setup the vars */
-                DecodeIPV6FragHeader(p, pkt, hdrextlen, plen,
-                        ip6_exthdrs_cnt, ip6_exthdrs);
+                DecodeIPV6FragHeader(p, pkt, hdrextlen, plen, prev_hdrextlen);
 
                 /* if FH has offset 0 and no more fragments are coming, we
                  * parse this packet further right away, no defrag will be
@@ -492,7 +462,7 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                 /* the rest is parsed upon reassembly */
                 p->flags |= PKT_IS_FRAGMENT;
                 SCReturn;
-
+            }
             case IPPROTO_ESP:
             {
                 IPV6_SET_L4PROTO(p,nh);
@@ -502,15 +472,6 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                     SCReturn;
                 }
 
-                if(ip6_exthdrs_cnt<IPV6_MAX_OPT)
-                {
-                    ip6_exthdrs[ip6_exthdrs_cnt].type = nh;
-                    ip6_exthdrs[ip6_exthdrs_cnt].next = IPPROTO_NONE;
-                    ip6_exthdrs[ip6_exthdrs_cnt].len = hdrextlen;
-                    ip6_exthdrs[ip6_exthdrs_cnt].data = pkt+2;
-                    ip6_exthdrs_cnt++;
-                }
-
                 if (eh) {
                     ENGINE_SET_EVENT(p, IPV6_EXTHDR_DUPL_EH);
                     SCReturn;
@@ -545,15 +506,6 @@ DecodeIPV6ExtHdrs(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt
                     ENGINE_SET_EVENT(p, IPV6_EXTHDR_AH_RES_NOT_NULL);
                 }
 
-                if(ip6_exthdrs_cnt < IPV6_MAX_OPT)
-                {
-                    ip6_exthdrs[ip6_exthdrs_cnt].type = nh;
-                    ip6_exthdrs[ip6_exthdrs_cnt].next = *pkt;
-                    ip6_exthdrs[ip6_exthdrs_cnt].len = hdrextlen;
-                    ip6_exthdrs[ip6_exthdrs_cnt].data = pkt+2;
-                    ip6_exthdrs_cnt++;
-                }
-
                 if (ah) {
                     ENGINE_SET_EVENT(p, IPV6_EXTHDR_DUPL_AH);
                     nh = *pkt;
diff --git a/src/defrag.c b/src/defrag.c
index fd89a757f5..7004918c77 100644
--- a/src/defrag.c
+++ b/src/defrag.c
@@ -1073,7 +1073,7 @@ error:
 
 void DecodeIPV6FragHeader(Packet *p, uint8_t *pkt,
                           uint16_t hdrextlen, uint16_t plen,
-                          uint16_t ip6_exthdrs_cnt, IPV6GenOptHdr *ip6_exthdrs);
+                          uint16_t prev_hdrextlen);
 
 static Packet *
 IPV6BuildTestPacket(uint32_t id, uint16_t off, int mf, const char content,
@@ -1115,7 +1115,7 @@ IPV6BuildTestPacket(uint32_t id, uint16_t off, int mf, const char content,
     fh->ip6fh_ident = htonl(id);
     fh->ip6fh_offlg = htons((off << 3) | mf);
 
-    DecodeIPV6FragHeader(p, (uint8_t *)fh, 8, 8 + content_len, 0, NULL);
+    DecodeIPV6FragHeader(p, (uint8_t *)fh, 8, 8 + content_len, 0);
 
     pcontent = SCCalloc(1, content_len);
     if (unlikely(pcontent == NULL))