X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/e2826164d4518667c80fa14a93390c77af8b8af7..refs/heads/tcpdump-3.8:/print-tcp.c

diff --git a/print-tcp.c b/print-tcp.c
index 2b7c610c..9a965ff4 100644
--- a/print-tcp.c
+++ b/print-tcp.c
@@ -20,8 +20,8 @@
  */
 
 #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 1.107.2.5 2004-07-28 20:11:31 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -100,7 +100,7 @@ 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 +115,7 @@ 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 +131,9 @@ 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 +147,11 @@ 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 +160,10 @@ 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)
@@ -215,11 +212,12 @@ 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 (!qflag && hlen >= sizeof(*tp) && hlen <= length) {
 		if ((u_char *)tp + 4 + sizeof(struct rpc_msg) <= snapend &&
 		    dport == NFS_PORT) {
 			nfsreq_print((u_char *)tp + hlen + 4, length - hlen,
@@ -260,6 +258,12 @@ 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 +272,11 @@ 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 +402,8 @@ 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;
 	}
 
@@ -622,7 +631,7 @@ 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);
 		}