X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/e2826164d4518667c80fa14a93390c77af8b8af7..refs/heads/tcpdump-3.9:/print-tcp.c diff --git a/print-tcp.c b/print-tcp.c index 2b7c610c..9b6c2a2f 100644 --- a/print-tcp.c +++ b/print-tcp.c @@ -2,6 +2,8 @@ * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 * The Regents of the University of California. All rights reserved. * + * Copyright (c) 1999-2004 The tcpdump.org project + * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) @@ -20,8 +22,8 @@ */ #ifndef lint -static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.106 2003-10-28 03:16:36 itojun Exp $ (LBL)"; +static const char rcsid[] _U_ = + "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.120.2.3 2005-10-16 06:05:46 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H @@ -30,8 +32,6 @@ static const char rcsid[] = #include -#include - #include #include #include @@ -47,9 +47,22 @@ static const char rcsid[] = #include "ip6.h" #endif #include "ipproto.h" +#include "rpc_auth.h" +#include "rpc_msg.h" #include "nameser.h" +#ifdef HAVE_LIBCRYPTO +#include + +#define SIGNATURE_VALID 0 +#define SIGNATURE_INVALID 1 +#define CANT_CHECK_SIGNATURE 2 + +static int tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp, + const u_char *data, int length, const u_char *rcvsig); +#endif + static void print_tcp_rst_data(register const u_char *sp, u_int length); #define MAX_RST_DATA_LEN 30 @@ -100,7 +113,7 @@ static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE]; static int tcp_cksum(register const struct ip *ip, register const struct tcphdr *tp, - register int len) + register u_int len) { union phu { struct phdr { @@ -115,7 +128,7 @@ static int tcp_cksum(register const struct ip *ip, const u_int16_t *sp; /* pseudo-header.. */ - phu.ph.len = htons(len); /* XXX */ + phu.ph.len = htons((u_int16_t)len); phu.ph.mbz = 0; phu.ph.proto = IPPROTO_TCP; memcpy(&phu.ph.src, &ip->ip_src.s_addr, sizeof(u_int32_t)); @@ -131,9 +144,9 @@ static int tcp_cksum(register const struct ip *ip, #ifdef INET6 static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp, - int len) + u_int len) { - size_t i, tlen; + size_t i; register const u_int16_t *sp; u_int32_t sum; union { @@ -147,14 +160,11 @@ static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp, u_int16_t pa[20]; } phu; - tlen = EXTRACT_16BITS(&ip6->ip6_plen) + sizeof(struct ip6_hdr) - - ((const char *)tp - (const char*)ip6); - /* pseudo-header */ memset(&phu, 0, sizeof(phu)); phu.ph.ph_src = ip6->ip6_src; phu.ph.ph_dst = ip6->ip6_dst; - phu.ph.ph_len = htonl(tlen); + phu.ph.ph_len = htonl(len); phu.ph.ph_nxt = IPPROTO_TCP; sum = 0; @@ -163,10 +173,10 @@ static int tcp6_cksum(const struct ip6_hdr *ip6, const struct tcphdr *tp, sp = (const u_int16_t *)tp; - for (i = 0; i < (tlen & ~1); i += 2) + for (i = 0; i < (len & ~1); i += 2) sum += *sp++; - if (tlen & 1) + if (len & 1) sum += htons((*(const u_int8_t *)sp) << 8); while (sum > 0xffff) @@ -215,17 +225,18 @@ tcp_print(register const u_char *bp, register u_int length, hlen = TH_OFF(tp) * 4; /* - * If data present and NFS port used, assume NFS. + * If data present, header length valid, and NFS port used, + * assume NFS. * Pass offset of data plus 4 bytes for RPC TCP msg length * to NFS print routines. */ - if (!qflag) { - if ((u_char *)tp + 4 + sizeof(struct rpc_msg) <= snapend && + if (!qflag && hlen >= sizeof(*tp) && hlen <= length) { + if ((u_char *)tp + 4 + sizeof(struct sunrpc_msg) <= snapend && dport == NFS_PORT) { nfsreq_print((u_char *)tp + hlen + 4, length - hlen, (u_char *)ip); return; - } else if ((u_char *)tp + 4 + sizeof(struct rpc_msg) + } else if ((u_char *)tp + 4 + sizeof(struct sunrpc_msg) <= snapend && sport == NFS_PORT) { nfsreply_print((u_char *)tp + hlen + 4, length - hlen, @@ -260,6 +271,12 @@ tcp_print(register const u_char *bp, register u_int length, } } + if (hlen < sizeof(*tp)) { + (void)printf(" tcp %d [bad hdr length %u - too short, < %lu]", + length - hlen, hlen, (unsigned long)sizeof(*tp)); + return; + } + TCHECK(*tp); seq = EXTRACT_32BITS(&tp->th_seq); @@ -268,7 +285,11 @@ tcp_print(register const u_char *bp, register u_int length, urp = EXTRACT_16BITS(&tp->th_urp); if (qflag) { - (void)printf("tcp %d", length - TH_OFF(tp) * 4); + (void)printf("tcp %d", length - hlen); + if (hlen > length) { + (void)printf(" [bad hdr length %u - too long, > %u]", + hlen, length); + } return; } if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH| @@ -394,7 +415,8 @@ tcp_print(register const u_char *bp, register u_int length, thseq = thack = threv = 0; } if (hlen > length) { - (void)printf(" [bad hdr length]"); + (void)printf(" [bad hdr length %u - too long, > %u]", + hlen, length); return; } @@ -402,23 +424,27 @@ tcp_print(register const u_char *bp, register u_int length, u_int16_t sum, tcp_sum; if (TTEST2(tp->th_sport, length)) { sum = tcp_cksum(ip, tp, length); + + (void)printf(", cksum 0x%04x",EXTRACT_16BITS(&tp->th_sum)); if (sum != 0) { tcp_sum = EXTRACT_16BITS(&tp->th_sum); - (void)printf(" [bad tcp cksum %x (->%x)!]", - tcp_sum, in_cksum_shouldbe(tcp_sum, sum)); + (void)printf(" (incorrect (-> 0x%04x),",in_cksum_shouldbe(tcp_sum, sum)); } else - (void)printf(" [tcp sum ok]"); + (void)printf(" (correct),"); } } #ifdef INET6 if (IP_V(ip) == 6 && ip6->ip6_plen && vflag && !fragmented) { - int sum; + u_int16_t sum,tcp_sum; if (TTEST2(tp->th_sport, length)) { sum = tcp6_cksum(ip6, tp, length); - if (sum != 0) - (void)printf(" [bad tcp cksum %x!]", sum); - else - (void)printf(" [tcp sum ok]"); + (void)printf(", cksum 0x%04x",EXTRACT_16BITS(&tp->th_sum)); + if (sum != 0) { + tcp_sum = EXTRACT_16BITS(&tp->th_sum); + (void)printf(" (incorrect (-> 0x%04x),",in_cksum_shouldbe(tcp_sum, sum)); + } else + (void)printf(" (correct),"); + } } #endif @@ -494,14 +520,13 @@ tcp_print(register const u_char *bp, register u_int length, break; case TCPOPT_SACK: - (void)printf("sack"); datalen = len - 2; if (datalen % 8 != 0) { - (void)printf(" malformed sack "); + (void)printf("malformed sack"); } else { u_int32_t s, e; - (void)printf(" sack %d ", datalen / 8); + (void)printf("sack %d ", datalen / 8); for (i = 0; i < datalen; i += 8) { LENCHECK(i + 4); s = EXTRACT_32BITS(cp + i); @@ -516,7 +541,6 @@ tcp_print(register const u_char *bp, register u_int length, } (void)printf("{%u:%u}", s, e); } - (void)printf(" "); } break; @@ -564,6 +588,34 @@ tcp_print(register const u_char *bp, register u_int length, (void)printf(" %u", EXTRACT_32BITS(cp)); break; + case TCPOPT_SIGNATURE: + (void)printf("md5:"); + datalen = TCP_SIGLEN; + LENCHECK(datalen); +#ifdef HAVE_LIBCRYPTO + switch (tcp_verify_signature(ip, tp, + bp + TH_OFF(tp) * 4, length, cp)) { + + case SIGNATURE_VALID: + (void)printf("valid"); + break; + + case SIGNATURE_INVALID: + (void)printf("invalid"); + break; + + case CANT_CHECK_SIGNATURE: + (void)printf("can't check - "); + for (i = 0; i < TCP_SIGLEN; ++i) + (void)printf("%02x", cp[i]); + break; + } +#else + for (i = 0; i < TCP_SIGLEN; ++i) + (void)printf("%02x", cp[i]); +#endif + break; + default: (void)printf("opt-%u:", opt); datalen = len - 2; @@ -622,12 +674,13 @@ tcp_print(register const u_char *bp, register u_int length, * TCP DNS query has 2byte length at the head. * XXX packet could be unaligned, it can go strange */ - ns_print(bp + 2, length - 2); + ns_print(bp + 2, length - 2, 0); } else if (sport == MSDP_PORT || dport == MSDP_PORT) { msdp_print(bp, length); } - else if (sport == LDP_PORT || dport == LDP_PORT) - printf(": LDP, length: %u", length); + else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) { + ldp_print(bp, length); + } } return; bad: @@ -676,3 +729,79 @@ print_tcp_rst_data(register const u_char *sp, u_int length) } putchar(']'); } + +#ifdef HAVE_LIBCRYPTO +static int +tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp, + const u_char *data, int length, const u_char *rcvsig) +{ + struct tcphdr tp1; + u_char sig[TCP_SIGLEN]; + char zero_proto = 0; + MD5_CTX ctx; + u_int16_t savecsum, tlen; +#ifdef INET6 + struct ip6_hdr *ip6; +#endif + u_int32_t len32; + u_int8_t nxt; + + tp1 = *tp; + + if (tcpmd5secret == NULL) + return (CANT_CHECK_SIGNATURE); + + MD5_Init(&ctx); + /* + * Step 1: Update MD5 hash with IP pseudo-header. + */ + if (IP_V(ip) == 4) { + MD5_Update(&ctx, (char *)&ip->ip_src, sizeof(ip->ip_src)); + MD5_Update(&ctx, (char *)&ip->ip_dst, sizeof(ip->ip_dst)); + MD5_Update(&ctx, (char *)&zero_proto, sizeof(zero_proto)); + MD5_Update(&ctx, (char *)&ip->ip_p, sizeof(ip->ip_p)); + tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4; + tlen = htons(tlen); + MD5_Update(&ctx, (char *)&tlen, sizeof(tlen)); +#ifdef INET6 + } else if (IP_V(ip) == 6) { + ip6 = (struct ip6_hdr *)ip; + MD5_Update(&ctx, (char *)&ip6->ip6_src, sizeof(ip6->ip6_src)); + MD5_Update(&ctx, (char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst)); + len32 = htonl(ntohs(ip6->ip6_plen)); + MD5_Update(&ctx, (char *)&len32, sizeof(len32)); + nxt = 0; + MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); + MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); + MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); + nxt = IPPROTO_TCP; + MD5_Update(&ctx, (char *)&nxt, sizeof(nxt)); +#endif + } else + return (CANT_CHECK_SIGNATURE); + + /* + * Step 2: Update MD5 hash with TCP header, excluding options. + * The TCP checksum must be set to zero. + */ + savecsum = tp1.th_sum; + tp1.th_sum = 0; + MD5_Update(&ctx, (char *)&tp1, sizeof(struct tcphdr)); + tp1.th_sum = savecsum; + /* + * Step 3: Update MD5 hash with TCP segment data, if present. + */ + if (length > 0) + MD5_Update(&ctx, data, length); + /* + * Step 4: Update MD5 hash with shared secret. + */ + MD5_Update(&ctx, tcpmd5secret, strlen(tcpmd5secret)); + MD5_Final(sig, &ctx); + + if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0) + return (SIGNATURE_VALID); + else + return (SIGNATURE_INVALID); +} +#endif /* HAVE_LIBCRYPTO */