Add some additional bounds checking.

[tcpdump] / print-tcp.c

diff --git a/print-tcp.c b/print-tcp.c
index 90f51a4cf2b445188af4fda6f4f21af5bfe068a4..025e50d23f375e600e84e8d5ece2cf5341ddb76a 100644 (file)
--- 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 1.114 2004-04-26 06:17:31 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.119 2004-12-27 00:41:31 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -30,8 +30,6 @@ static const char rcsid[] _U_ =
 
 #include <tcpdump-stdinc.h>
 
-#include <rpc/rpc.h>
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -47,12 +45,18 @@ static const char rcsid[] _U_ =
 #include "ip6.h"
 #endif
 #include "ipproto.h"
+#include "rpc_auth.h"
+#include "rpc_msg.h"
 
 #include "nameser.h"
 
 #ifdef HAVE_LIBCRYPTO
 #include <openssl/md5.h>
 
+#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
@@ -219,17 +223,18 @@ 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,
@@ -264,6 +269,12 @@ 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);
@@ -272,7 +283,11 @@ 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|
@@ -398,7 +413,8 @@ 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;
        }
 
@@ -577,11 +593,23 @@ tcp_print(register const u_char *bp, register u_int length,
                                datalen = TCP_SIGLEN;
                                LENCHECK(datalen);
 #ifdef HAVE_LIBCRYPTO
-                               if (tcp_verify_signature(ip, tp,
-                                   bp + TH_OFF(tp) * 4, length, cp) == 0)
+                               switch (tcp_verify_signature(ip, tp,
+                                   bp + TH_OFF(tp) * 4, length, cp)) {
+
+                               case SIGNATURE_VALID:
                                        (void)printf("valid");
-                               else
+                                       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]);
@@ -650,8 +678,9 @@ tcp_print(register const u_char *bp, register u_int length,
                } 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:
@@ -711,14 +740,16 @@ tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
        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 (-1);
+               return (CANT_CHECK_SIGNATURE);
 
        MD5_Init(&ctx);
        /*
@@ -732,6 +763,7 @@ tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
                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));
@@ -744,8 +776,9 @@ tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
                MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
                nxt = IPPROTO_TCP;
                MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
+#endif
        } else
-               return (-1);
+               return (CANT_CHECK_SIGNATURE);
 
        /*
         * Step 2: Update MD5 hash with TCP header, excluding options.
@@ -766,6 +799,9 @@ tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
        MD5_Update(&ctx, tcpmd5secret, strlen(tcpmd5secret));
        MD5_Final(sig, &ctx);
 
-       return (memcmp(rcvsig, sig, 16));
+       if (memcmp(rcvsig, sig, 16))
+               return (SIGNATURE_VALID);
+       else
+               return (SIGNATURE_INVALID);
 }
 #endif /* HAVE_LIBCRYPTO */