X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/bbc1cfa669a5f51ed26bae3784447076e3fbc80f..f1fa25bfefac7dd95768d949ef0ef232c4540331:/print-tcp.c

diff --git a/print-tcp.c b/print-tcp.c
index 44279215..86195a85 100644
--- a/print-tcp.c
+++ b/print-tcp.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.109 2003-11-16 09:36:39 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.112 2004-04-05 00:12:54 mcr Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -50,6 +50,13 @@ static const char rcsid[] _U_ =
 
 #include "nameser.h"
 
+#ifdef HAVE_LIBCRYPTO
+#include <openssl/md5.h>
+
+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 +107,7 @@ 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 +122,7 @@ 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 +138,9 @@ 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 +154,11 @@ 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 +167,10 @@ 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)
@@ -564,6 +568,26 @@ tcp_print(register const u_char *bp, register u_int length,
 				(void)printf(" %u", EXTRACT_32BITS(cp));
 				break;
 
+			case TCPOPT_SIGNATURE:
+				(void)printf("md5:");
+				if (IP_V(ip) != 4) {
+					(void)printf("!ipv4");
+					break;
+				}
+				datalen = TCP_SIGLEN;
+				LENCHECK(datalen);
+#ifdef HAVE_LIBCRYPTO
+				if (tcp_verify_signature(ip, tp,
+				    bp + TH_OFF(tp) * 4, length, cp) == 0)
+					(void)printf("valid");
+				else
+					(void)printf("invalid");
+#else
+				for (i = 0; i < TCP_SIGLEN; ++i)
+					(void)printf("%02x", cp[i]);
+#endif
+				break;
+
 			default:
 				(void)printf("opt-%u:", opt);
 				datalen = len - 2;
@@ -676,3 +700,54 @@ 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;
+	char sig[TCP_SIGLEN];
+	char zero_proto = 0;
+	MD5_CTX ctx;
+	u_short savecsum, tlen;
+
+	tp1 = *tp;
+
+	if (tcpmd5secret == NULL)
+		return (-1);
+
+	MD5_Init(&ctx);
+	/*
+	 * Step 1: Update MD5 hash with IP pseudo-header.
+	 */
+	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));
+
+	/*
+	 * 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);
+
+	return (memcmp(rcvsig, sig, 16));
+}
+#endif /* HAVE_LIBCRYPTO */