X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/6a66f110963d96a92de4f4d2e757ef2893c3c3ee..0023eaa78f123676bfa9c5fba72ea4b8a59aaa70:/print-ip6.c diff --git a/print-ip6.c b/print-ip6.c index 6fef7ba9..269b41fb 100644 --- a/print-ip6.c +++ b/print-ip6.c @@ -21,9 +21,7 @@ /* \summary: IPv6 printer */ -#ifdef HAVE_CONFIG_H #include -#endif #include "netdissect-stdinc.h" @@ -77,7 +75,6 @@ ip6_finddst(netdissect_options *ndo, nd_ipv6 *dst, * the header, in units of 8 octets, excluding * the first 8 octets. */ - ND_TCHECK_2(cp); advance = (GET_U_1(cp + 1) + 1) << 3; nh = GET_U_1(cp); break; @@ -88,7 +85,6 @@ ip6_finddst(netdissect_options *ndo, nd_ipv6 *dst, * marked as reserved, and the header is always * the same size. */ - ND_TCHECK_1(cp); advance = sizeof(struct ip6_frag); nh = GET_U_1(cp); break; @@ -233,28 +229,23 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) u_int total_advance; const u_char *cp; uint32_t payload_len; - uint8_t nh; + uint8_t ph, nh; int fragmented = 0; u_int flow; int found_extension_header; int found_jumbo; + int found_hbh; ndo->ndo_protocol = "ip6"; ip6 = (const struct ip6_hdr *)bp; - ND_TCHECK_SIZE(ip6); - if (length < sizeof (struct ip6_hdr)) { - ND_PRINT("truncated-ip6 %u", length); - return; + if (!ndo->ndo_eflag) { + nd_print_protocol_caps(ndo); + ND_PRINT(" "); } - if (!ndo->ndo_eflag) - ND_PRINT("IP6 "); - - if (IP6_VERSION(ip6) != 6) { - ND_PRINT("version error: %u != 6", IP6_VERSION(ip6)); - return; - } + ND_ICHECK_ZU(length, <, sizeof (struct ip6_hdr)); + ND_ICHECKMSG_U("version", IP6_VERSION(ip6), !=, 6); payload_len = GET_BE_U_2(ip6->ip6_plen); /* @@ -281,41 +272,43 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) */ if (payload_len != 0) { len = payload_len + sizeof(struct ip6_hdr); - if (length < len) - ND_PRINT("truncated-ip6 - %u bytes missing!", - len - length); + if (len > length) { + ND_PRINT("[header+payload length %u > length %u]", + len, length); + nd_print_invalid(ndo); + ND_PRINT(" "); + } } else len = length + sizeof(struct ip6_hdr); - nh = GET_U_1(ip6->ip6_nxt); - if (ndo->ndo_vflag) { - flow = GET_BE_U_4(ip6->ip6_flow); - ND_PRINT("("); -#if 0 - /* rfc1883 */ - if (flow & 0x0f000000) - ND_PRINT("pri 0x%02x, ", (flow & 0x0f000000) >> 24); - if (flow & 0x00ffffff) - ND_PRINT("flowlabel 0x%06x, ", flow & 0x00ffffff); -#else - /* RFC 2460 */ - if (flow & 0x0ff00000) - ND_PRINT("class 0x%02x, ", (flow & 0x0ff00000) >> 20); - if (flow & 0x000fffff) - ND_PRINT("flowlabel 0x%05x, ", flow & 0x000fffff); -#endif - - ND_PRINT("hlim %u, next-header %s (%u) payload length: %u) ", - GET_U_1(ip6->ip6_hlim), - tok2str(ipproto_values,"unknown",nh), - nh, - payload_len); - } + ph = 255; + nh = GET_U_1(ip6->ip6_nxt); + if (ndo->ndo_vflag) { + flow = GET_BE_U_4(ip6->ip6_flow); + ND_PRINT("("); + /* RFC 2460 */ + if (flow & 0x0ff00000) + ND_PRINT("class 0x%02x, ", (flow & 0x0ff00000) >> 20); + if (flow & 0x000fffff) + ND_PRINT("flowlabel 0x%05x, ", flow & 0x000fffff); + + ND_PRINT("hlim %u, next-header %s (%u), payload length %u) ", + GET_U_1(ip6->ip6_hlim), + tok2str(ipproto_values,"unknown",nh), + nh, + payload_len); + } + ND_TCHECK_SIZE(ip6); /* - * Cut off the snapshot length to the end of the IP payload. + * Cut off the snapshot length to the end of the IP payload + * or the end of the data in which it's contained, whichever + * comes first. */ - nd_push_snapend(ndo, bp + len); + if (!nd_push_snaplen(ndo, bp, ND_MIN(length, len))) { + (*ndo->ndo_error)(ndo, S_ERR_ND_MEM_ALLOC, + "%s: can't push snaplen on buffer stack", __func__); + } cp = (const u_char *)ip6; advance = sizeof(struct ip6_hdr); @@ -323,6 +316,7 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) /* Process extension headers */ found_extension_header = 0; found_jumbo = 0; + found_hbh = 0; while (cp < ndo->ndo_snapend && advance > 0) { if (len < (u_int)advance) goto trunc; @@ -334,18 +328,38 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) nh != IPPROTO_TCP && nh != IPPROTO_UDP && nh != IPPROTO_DCCP && nh != IPPROTO_SCTP) { ND_PRINT("%s > %s: ", GET_IP6ADDR_STRING(ip6->ip6_src), - GET_IP6ADDR_STRING(ip6->ip6_dst)); + GET_IP6ADDR_STRING(ip6->ip6_dst)); } switch (nh) { case IPPROTO_HOPOPTS: + /* + * The Hop-by-Hop Options header, when present, + * must immediately follow the IPv6 header (RFC 8200) + */ + if (found_hbh == 1) { + ND_PRINT("[The Hop-by-Hop Options header was already found]"); + nd_print_invalid(ndo); + return; + } + if (ph != 255) { + ND_PRINT("[The Hop-by-Hop Options header don't follow the IPv6 header]"); + nd_print_invalid(ndo); + return; + } advance = hbhopt_process(ndo, cp, &found_jumbo, &payload_len); + if (payload_len == 0 && found_jumbo == 0) { + ND_PRINT("[No valid Jumbo Payload Hop-by-Hop option found]"); + nd_print_invalid(ndo); + return; + } if (advance < 0) { nd_pop_packet_info(ndo); return; } found_extension_header = 1; + found_hbh = 1; nh = GET_U_1(cp); break; @@ -373,10 +387,10 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) case IPPROTO_MOBILITY_OLD: case IPPROTO_MOBILITY: /* - * XXX - we don't use "advance"; RFC 3775 says that + * RFC 3775 says that * the next header field in a mobility header * should be IPPROTO_NONE, but speaks of - * the possiblity of a future extension in + * the possibility of a future extension in * which payload can be piggybacked atop a * mobility header. */ @@ -420,10 +434,13 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) len = payload_len + sizeof(struct ip6_hdr); if (len < total_advance) goto trunc; - if (length < len) - ND_PRINT("truncated-ip6 - %u bytes missing!", - len - length); - nd_change_snapend(ndo, bp + len); + if (len > length) { + ND_PRINT("[header+payload length %u > length %u]", + len, length); + nd_print_invalid(ndo); + ND_PRINT(" "); + } + nd_change_snaplen(ndo, bp, len); /* * Now subtract the length of the IPv6 @@ -448,7 +465,7 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) goto trunc; /* - * OK, we didn't see any extnesion + * OK, we didn't see any extension * header, but that means we have * no payload, so set the length * to the IPv6 header length, @@ -456,7 +473,7 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) * accordingly. */ len = sizeof(struct ip6_hdr); - nd_change_snapend(ndo, bp + len); + nd_change_snaplen(ndo, bp, len); /* * Now subtract the length of @@ -469,10 +486,11 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) } } ip_demux_print(ndo, cp, len, 6, fragmented, - GET_U_1(ip6->ip6_hlim), nh, bp); + GET_U_1(ip6->ip6_hlim), nh, bp); nd_pop_packet_info(ndo); return; } + ph = nh; /* ndo_protocol reassignment after xxx_print() calls */ ndo->ndo_protocol = "ip6"; @@ -482,4 +500,8 @@ ip6_print(netdissect_options *ndo, const u_char *bp, u_int length) return; trunc: nd_print_trunc(ndo); + return; + +invalid: + nd_print_invalid(ndo); }