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@@ -42,6 +42,10 @@ extern const char pcap_version[];
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#define JUNIPER_FLAG_NO_L2 0x02 /* L2 header */
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#define JUNIPER_FLAG_EXT 0x80 /* Juniper extensions present */
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#define JUNIPER_PCAP_MAGIC "MGC"
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+
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+static void *
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+get_ipv6_next(struct tcpr_ipv6_ext_hdr_base *exthdr, const u_char *end_ptr);
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+
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/**
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* Depending on what version of libpcap/WinPcap there are different ways to get
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* the version of the libpcap/WinPcap library. This presents a unified way to
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@@ -94,7 +98,7 @@ int parse_mpls(const u_char *pktdata,
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uint32_t *l2offset)
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{
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struct tcpr_mpls_label *mpls_label;
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- int len_remaining = (int)datalen;
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+ const u_char *end_ptr = pktdata + datalen;
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u_char first_nibble;
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eth_hdr_t *eth_hdr;
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bool bos = false;
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@@ -109,12 +113,11 @@ int parse_mpls(const u_char *pktdata,
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/* move over MPLS labels until we get to the last one */
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while (!bos) {
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- if (len_remaining < (int)sizeof(*mpls_label))
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+ if (pktdata + len + sizeof(*mpls_label) > end_ptr)
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return -1;
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mpls_label = (struct tcpr_mpls_label*)(pktdata + len);
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len += sizeof(*mpls_label);
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- len_remaining -= sizeof(*mpls_label);
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bos = (ntohl(mpls_label->entry) & MPLS_LS_S_MASK) != 0;
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label = ntohl(mpls_label->entry) >> MPLS_LS_LABEL_SHIFT;
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if (label == MPLS_LABEL_GACH) {
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@@ -124,7 +127,7 @@ int parse_mpls(const u_char *pktdata,
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}
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}
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- if (len_remaining < 4)
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+ if ((u_char*)mpls_label + 1 > end_ptr)
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return -1;
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first_nibble = *((u_char *)(mpls_label + 1)) >> 4;
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@@ -139,11 +142,10 @@ int parse_mpls(const u_char *pktdata,
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/* EoMPLS - jump over PW Ethernet Control Word and handle
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* inner Ethernet header
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*/
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- len += 4;
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- len_remaining -= 4;
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- if (len_remaining < (int)sizeof(*eth_hdr))
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+ if (pktdata + len + 4 + sizeof(*eth_hdr) > end_ptr)
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return -1;
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+ len += 4;
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*l2offset = len;
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eth_hdr = (eth_hdr_t*)(pktdata + len);
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len += sizeof(*eth_hdr);
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@@ -270,6 +272,7 @@ int get_l2len_protocol(const u_char *pktdata,
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*vlan_offset = 0;
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switch (datalink) {
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+ case DLT_NULL:
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case DLT_RAW:
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if (datalen == 0)
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return -1;
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@@ -317,13 +320,15 @@ int get_l2len_protocol(const u_char *pktdata,
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/* fall through */
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case DLT_EN10MB:
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{
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- eth_hdr_t *eth_hdr = (eth_hdr_t*)(pktdata + *l2offset);
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+ eth_hdr_t *eth_hdr;
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+ uint16_t ether_type;
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uint32_t l2_net_off = sizeof(*eth_hdr) + *l2offset;
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- uint16_t ether_type = ntohs(eth_hdr->ether_type);
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if (datalen <= l2_net_off)
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return -1;
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+ eth_hdr = (eth_hdr_t*)(pktdata + *l2offset);
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+ ether_type = ntohs(eth_hdr->ether_type);
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if (parse_metadata(pktdata,
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datalen,
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ðer_type,
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@@ -332,7 +337,7 @@ int get_l2len_protocol(const u_char *pktdata,
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vlan_offset))
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return -1;
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- if (datalen < l2_net_off)
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+ if (datalen <= l2_net_off)
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return -1;
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*l2len = l2_net_off;
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@@ -568,15 +573,16 @@ get_ipv6(const u_char *pktdata, int datalen, int datalink, u_char **newbuff)
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* If the packet is to short, returns NULL
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*/
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void *
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-get_layer4_v4(const ipv4_hdr_t *ip_hdr, const int l3len)
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+get_layer4_v4(const ipv4_hdr_t *ip_hdr, const u_char *end_ptr)
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{
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void *ptr;
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assert(ip_hdr);
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+ assert(end_ptr);
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ptr = (u_char *)ip_hdr + (ip_hdr->ip_hl << 2);
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/* make sure we don't jump over the end of the buffer */
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- if ((u_char *)ptr > ((u_char *)ip_hdr + l3len))
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+ if ((u_char *)ptr > end_ptr)
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return NULL;
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return ((void *)ptr);
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@@ -588,24 +594,21 @@ get_layer4_v4(const ipv4_hdr_t *ip_hdr, const int l3len)
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* v6 Frag or ESP header. Function is recursive.
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*/
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void *
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-get_layer4_v6(const ipv6_hdr_t *ip6_hdr, const int l3len)
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+get_layer4_v6(const ipv6_hdr_t *ip6_hdr, const u_char *end_ptr)
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{
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struct tcpr_ipv6_ext_hdr_base *next, *exthdr;
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bool done = false;
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- uint32_t maxlen;
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uint8_t proto;
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- int min_len;
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assert(ip6_hdr);
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-
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- min_len = TCPR_IPV6_H + sizeof(struct tcpr_ipv6_ext_hdr_base);
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- if (l3len < min_len)
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- return NULL;
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+ assert(end_ptr);
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/* jump to the end of the IPv6 header */
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next = (struct tcpr_ipv6_ext_hdr_base *)((u_char *)ip6_hdr + TCPR_IPV6_H);
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- proto = ip6_hdr->ip_nh;
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+ if ((u_char*)next > end_ptr)
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+ return NULL;
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+ proto = ip6_hdr->ip_nh;
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while (!done) {
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dbgx(3, "Processing proto: 0x%hx", (uint16_t)proto);
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@@ -613,7 +616,7 @@ get_layer4_v6(const ipv6_hdr_t *ip6_hdr, const int l3len)
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/* recurse due to v6-in-v6, need to recast next as an IPv6 Header */
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case TCPR_IPV6_NH_IPV6:
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dbg(3, "recursing due to v6-in-v6");
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- next = get_layer4_v6((ipv6_hdr_t *)next, l3len - min_len);
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+ next = get_layer4_v6((ipv6_hdr_t *)next, end_ptr);
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break;
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/* loop again */
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@@ -622,9 +625,9 @@ get_layer4_v6(const ipv6_hdr_t *ip6_hdr, const int l3len)
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case TCPR_IPV6_NH_DESTOPTS:
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case TCPR_IPV6_NH_HBH:
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dbgx(3, "Going deeper due to extension header 0x%02X", proto);
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- maxlen = l3len - (int)((u_char *)ip6_hdr - (u_char *)next);
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- exthdr = get_ipv6_next(next, maxlen);
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+ exthdr = get_ipv6_next(next, end_ptr);
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if (exthdr == NULL) {
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+ next = NULL;
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done = true;
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break;
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}
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@@ -655,10 +658,10 @@ get_layer4_v6(const ipv6_hdr_t *ip6_hdr, const int l3len)
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done = true;
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} /* switch */
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- } /* while */
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- if (!next || (u_char*)next > (u_char*)ip6_hdr + l3len)
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- return NULL;
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+ if (next == NULL)
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+ done = true;
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+ } /* while */
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return next;
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}
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@@ -668,15 +671,15 @@ get_layer4_v6(const ipv6_hdr_t *ip6_hdr, const int l3len)
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* returns the next payload or header of the current extension header
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* returns NULL for none/ESP.
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*/
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-void *
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-get_ipv6_next(struct tcpr_ipv6_ext_hdr_base *exthdr, const int len)
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+static void *
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+get_ipv6_next(struct tcpr_ipv6_ext_hdr_base *exthdr, const u_char *end_ptr)
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{
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- int extlen = 0;
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- int maxlen;
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- void *ptr;
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+ uint8_t extlen = 0;
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+ u_char *ptr;
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assert(exthdr);
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- maxlen = *((int*)((u_char *)exthdr + len));
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+ if ((u_char*)exthdr + sizeof(*exthdr) > end_ptr)
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+ return NULL;
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dbgx(3, "Jumping to next IPv6 header. Processing 0x%02x", exthdr->ip_nh);
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switch (exthdr->ip_nh) {
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@@ -695,9 +698,9 @@ get_ipv6_next(struct tcpr_ipv6_ext_hdr_base *exthdr, const int len)
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case TCPR_IPV6_NH_FRAGMENT:
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dbg(3, "Looks like were a fragment header. Returning some frag'd data.");
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ptr = (void *)((u_char *)exthdr + sizeof(struct tcpr_ipv6_frag_hdr));
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- if (*(int*)ptr > maxlen)
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+ if (ptr > end_ptr)
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return NULL;
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- return ptr;
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+ return (void *)ptr;
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break;
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/* all the rest require us to go deeper using the ip_len field */
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@@ -708,11 +711,11 @@ get_ipv6_next(struct tcpr_ipv6_ext_hdr_base *exthdr, const int len)
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case TCPR_IPV6_NH_AH:
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extlen = IPV6_EXTLEN_TO_BYTES(exthdr->ip_len);
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dbgx(3, "Looks like we're an ext header (0x%hhx). Jumping %u bytes"
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- " to the next", exthdr->ip_nh, extlen);
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- ptr = (void *)((u_char *)exthdr + extlen);
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- if (*(int*)ptr > maxlen)
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+ " to the next", exthdr->ip_nh, extlen);
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+ ptr = (u_char *)exthdr + extlen;
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+ if (ptr > end_ptr)
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return NULL;
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- return ptr;
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+ return (void *)ptr;
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break;
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default:
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@@ -727,7 +730,7 @@ get_ipv6_next(struct tcpr_ipv6_ext_hdr_base *exthdr, const int len)
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* the extension headers
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*/
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uint8_t
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-get_ipv6_l4proto(const ipv6_hdr_t *ip6_hdr, const int l3len)
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+get_ipv6_l4proto(const ipv6_hdr_t *ip6_hdr, const u_char *end_ptr)
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{
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u_char *ptr = (u_char *)ip6_hdr + TCPR_IPV6_H; /* jump to the end of the IPv6 header */
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uint8_t proto;
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@@ -735,15 +738,15 @@ get_ipv6_l4proto(const ipv6_hdr_t *ip6_hdr, const int l3len)
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assert(ip6_hdr);
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- proto = ip6_hdr->ip_nh;
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- int l4len = l3len - TCPR_IPV6_H;
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- if (l4len < 0)
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- return proto;
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+ if (ptr > end_ptr)
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+ return TCPR_IPV6_NH_NO_NEXT;
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+ proto = ip6_hdr->ip_nh;
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while (TRUE) {
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dbgx(3, "Processing next proto 0x%02X", proto);
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switch (proto) {
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/* no further processing for IPV6 types with nothing beyond them */
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+ case TCPR_IPV6_NH_NO_NEXT:
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case TCPR_IPV6_NH_FRAGMENT:
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case TCPR_IPV6_NH_ESP:
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dbg(3, "No-Next or ESP... can't go any further...");
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@@ -753,7 +756,7 @@ get_ipv6_l4proto(const ipv6_hdr_t *ip6_hdr, const int l3len)
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/* recurse */
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case TCPR_IPV6_NH_IPV6:
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dbg(3, "Recursing due to v6 in v6");
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- return get_ipv6_l4proto((ipv6_hdr_t *)ptr, l4len);
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+ return get_ipv6_l4proto((ipv6_hdr_t *)ptr, end_ptr);
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break;
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/* loop again */
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@@ -763,11 +766,10 @@ get_ipv6_l4proto(const ipv6_hdr_t *ip6_hdr, const int l3len)
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case TCPR_IPV6_NH_HBH:
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dbgx(3, "Jumping to next extension header (0x%hhx)", proto);
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exthdr = get_ipv6_next((struct tcpr_ipv6_ext_hdr_base *)ptr,
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- l4len);
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- if (exthdr == NULL)
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- return proto;
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+ end_ptr);
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+ if (exthdr == NULL || (u_char*)exthdr + sizeof(*exthdr) > end_ptr)
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+ return TCPR_IPV6_NH_NO_NEXT;
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proto = exthdr->ip_nh;
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- l4len -= (u_char *)exthdr - ptr;
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ptr = (u_char *)exthdr;
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break;
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