support DNAME and bit string label. more pedantic snapend validation.

{jinmei,itojun}@kame.net

diff --git a/nameser.h b/nameser.h
index 3218381e4d70a2a8a6ffd76b30337ee699d46c5d..9a72a2e9a5fac6ee64783300932c963901846ab3 100644 (file)
--- a/nameser.h
+++ b/nameser.h
@@ -1,4 +1,4 @@
-/* @(#) $Header: /tcpdump/master/tcpdump/nameser.h,v 1.4 2000-12-17 23:07:49 guy Exp $ (LBL) */
+/* @(#) $Header: /tcpdump/master/tcpdump/nameser.h,v 1.5 2000-12-28 20:30:41 itojun Exp $ (LBL) */

 /*
  * Copyright (c) 1983, 1989, 1993
  *     The Regents of the University of California.  All rights reserved.
 /*
  * Copyright (c) 1983, 1989, 1993
  *     The Regents of the University of California.  All rights reserved.


@@ -188,9 +188,11 @@ typedef struct {
 #define DNS_RCODE(np)  ((np)->flags2 & 0xF)    /* response code */
 
 /*
 #define DNS_RCODE(np)  ((np)->flags2 & 0xF)    /* response code */
 
 /*

- * Defines for handling compressed domain names
+ * Defines for handling compressed domain names, EDNS0 labels, etc.

  */
  */

-#define INDIR_MASK     0xc0
+#define INDIR_MASK     0xc0    /* 11.... */
+#define EDNS0_MASK     0x40    /* 01.... */
+#  define EDNS0_ELT_BITLABEL 0x01 

 
 /*
  * Structure for passing resource records around.
 
 /*
  * Structure for passing resource records around.

diff --git a/print-domain.c b/print-domain.c
index 9d84c544a81806f6ee46ce651d4e5c3f0a70ca49..50aaed3852b34183d5121577e72b1363ad33300b 100644 (file)
--- a/print-domain.c
+++ b/print-domain.c
@@ -21,7 +21,7 @@
 
 #ifndef lint
 static const char rcsid[] =
 
 #ifndef lint
 static const char rcsid[] =

-    "@(#) $Header: /tcpdump/master/tcpdump/print-domain.c,v 1.57 2000-12-27 12:23:27 itojun Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/tcpdump/print-domain.c,v 1.58 2000-12-28 20:30:42 itojun Exp $ (LBL)";

 #endif
 
 #ifdef HAVE_CONFIG_H
 #endif
 
 #ifdef HAVE_CONFIG_H


@@ -110,7 +110,10 @@ static const char rcsid[] =
 #define T_NAPTR                35              /* Naming Authority PoinTeR */
 #endif
 #ifndef T_A6
 #define T_NAPTR                35              /* Naming Authority PoinTeR */
 #endif
 #ifndef T_A6

-#define T_A6           38              /* IP6 address (ipngwg-dns-lookups) */
+#define T_A6           38              /* IP6 address */
+#endif
+#ifndef T_DNAME
+#define T_DNAME                39              /* non-terminal redirection */

 #endif
 
 #ifndef T_UNSPEC
 #endif
 
 #ifndef T_UNSPEC


@@ -148,8 +151,22 @@ ns_nskip(register const u_char *cp, register const u_char *bp)
 
        if (((i = *cp++) & INDIR_MASK) == INDIR_MASK)
                return (cp + 1);
 
        if (((i = *cp++) & INDIR_MASK) == INDIR_MASK)
                return (cp + 1);

+       if (cp >= snapend)
+               return(NULL);

        while (i && cp < snapend) {
        while (i && cp < snapend) {

-               cp += i;
+               if ((i & INDIR_MASK) == EDNS0_MASK) {
+                       int bitlen, bytelen;
+
+                       if ((i & ~INDIR_MASK) != EDNS0_ELT_BITLABEL)
+                               return(NULL); /* unknown ELT */
+                       if ((bitlen = *cp++) == 0)
+                               bitlen = 256;
+                       bytelen = (bitlen + 7) / 8;
+                       cp += bytelen;
+               } else
+                       cp += i;
+               if (cp >= snapend)
+                       return(NULL);

                i = *cp++;
        }
        return (cp);
                i = *cp++;
        }
        return (cp);


@@ -157,26 +174,87 @@ ns_nskip(register const u_char *cp, register const u_char *bp)
 
 /* print a <domain-name> */
 static const u_char *
 
 /* print a <domain-name> */
 static const u_char *

-ns_nprint(register const u_char *cp, register const u_char *bp)
+blabel_print(const u_char *cp)
+{
+       int bitlen, bytelen;
+       int truncated = 0;
+       const u_char *bitp, *lim;
+
+       if (cp >= snapend)
+               return(NULL);
+       if ((bitlen = *cp) == 0)
+               bitlen = 256;
+       bytelen = (bitlen + 7) / 8;
+       if ((lim = cp + 1 + bytelen) > snapend) {
+               truncated = 1;
+               lim = snapend;
+       }
+
+       /* print the bit string as a hex string */
+       printf("\\[x");
+       for (bitp = cp + 1; bitp < lim; bitp++)
+               printf("%02x", *bitp);
+       if (truncated)
+               printf("...");
+       printf("/%d]", bitlen);
+
+       return(truncated ? NULL : lim);
+}
+
+static int
+labellen(const u_char *cp)

 {
        register u_int i;
 {
        register u_int i;

+
+       if (cp >= snapend)
+               return(-1);
+       i = *cp;
+       if ((i & INDIR_MASK) == EDNS0_MASK) {
+               int bitlen, elt;
+
+               if ((elt = (i & ~INDIR_MASK)) != EDNS0_ELT_BITLABEL)
+                       return(-1);
+               if (cp + 1 >= snapend)
+                       return(-1);
+               if ((bitlen = *(cp + 1)) == 0)
+                       bitlen = 256;
+               return(((bitlen + 7) / 8) + 1);
+       } else
+               return(i);
+}
+
+static const u_char *
+ns_nprint(register const u_char *cp, register const u_char *bp)
+{
+       register u_int i, l;

        register const u_char *rp;
        register const u_char *rp;

-       register int compress;
+       register int compress = 0;

        int chars_processed;
        int chars_processed;

+       int elt;

        int data_size = snapend - bp;
 
        int data_size = snapend - bp;
 

-       i = *cp++;
+       if ((l = labellen(cp)) < 0)
+               return(NULL);
+       if (cp >= snapend)
+               return(NULL);

        chars_processed = 1;
        chars_processed = 1;

-       rp = cp + i;
-       if ((i & INDIR_MASK) == INDIR_MASK) {
-               rp = cp + 1;
-               compress = 1;
-       } else
+       if (((i = *cp++) & INDIR_MASK) != INDIR_MASK) {

                compress = 0;
                compress = 0;

+               rp = cp + l;
+       }
+

        if (i != 0)
                while (i && cp < snapend) {
                        if ((i & INDIR_MASK) == INDIR_MASK) {
        if (i != 0)
                while (i && cp < snapend) {
                        if ((i & INDIR_MASK) == INDIR_MASK) {

+                               if (!compress) {
+                                       rp = cp + 1;
+                                       compress = 1;
+                               }

                                cp = bp + (((i << 8) | *cp) & 0x3fff);
                                cp = bp + (((i << 8) | *cp) & 0x3fff);

+                               if (cp >= snapend)
+                                       return(NULL);
+                               if ((l = labellen(cp)) < 0)
+                                       return(NULL);

                                i = *cp++;
                                chars_processed++;
 
                                i = *cp++;
                                chars_processed++;
 


@@ -187,22 +265,36 @@ ns_nprint(register const u_char *cp, register const u_char *bp)
                                 * which means we're looping.
                                 */
                                if (chars_processed >= data_size) {
                                 * which means we're looping.
                                 */
                                if (chars_processed >= data_size) {

-                                       fn_printn(cp, 6, (u_char *)"<LOOP>");
-                                       if (!compress)
-                                               rp += i + 1;
-                                       return (rp);
+                                       printf("<LOOP>");
+                                       return (NULL);

                                }
                                continue;
                        }
                                }
                                continue;
                        }

-                       if (fn_printn(cp, i, snapend))
-                               break;
-                       cp += i;
-                       chars_processed += i;
+                       if ((i & INDIR_MASK) == EDNS0_MASK) {
+                               elt = (i & ~INDIR_MASK);
+                               switch(elt) {
+                               case EDNS0_ELT_BITLABEL:
+                                       blabel_print(cp);
+                                       break;
+                               default:
+                                       /* unknown ELT */
+                                       printf("<ELT %d>", elt);
+                                       return(NULL);
+                               }
+                       } else {
+                               if (fn_printn(cp, l, snapend))
+                                       break;
+                       }
+
+                       cp += l;
+                       chars_processed += l;

                        putchar('.');
                        putchar('.');

+                       if (cp >= snapend || (l = labellen(cp)) < 0)
+                               return(NULL);

                        i = *cp++;
                        chars_processed++;
                        if (!compress)
                        i = *cp++;
                        chars_processed++;
                        if (!compress)

-                               rp += i + 1;
+                               rp += l + 1;

                }
        else
                putchar('.');
                }
        else
                putchar('.');


@@ -215,6 +307,8 @@ ns_cprint(register const u_char *cp, register const u_char *bp)
 {
        register u_int i;
 
 {
        register u_int i;
 

+       if (cp >= snapend)
+               return NULL;

        i = *cp++;
        (void)fn_printn(cp, i, snapend);
        return (cp + i);
        i = *cp++;
        (void)fn_printn(cp, i, snapend);
        return (cp + i);


@@ -257,17 +351,9 @@ static struct tok type2str[] = {
        { T_ATMA,       "ATMA " },
        { T_NAPTR,      "NAPTR " },
        { T_A6,         "A6 " },
        { T_ATMA,       "ATMA " },
        { T_NAPTR,      "NAPTR " },
        { T_A6,         "A6 " },

-#ifndef T_UINFO
-#define T_UINFO 100
-#endif
+       { T_DNAME,      "DNAME " },

        { T_UINFO,      "UINFO" },
        { T_UINFO,      "UINFO" },

-#ifndef T_UID
-#define T_UID 101
-#endif

        { T_UID,        "UID" },
        { T_UID,        "UID" },

-#ifndef T_GID
-#define T_GID 102
-#endif

        { T_GID,        "GID" },
        { T_UNSPEC,     "UNSPEC" },
        { T_UNSPECA,    "UNSPECA" },
        { T_GID,        "GID" },
        { T_UNSPEC,     "UNSPEC" },
        { T_UNSPECA,    "UNSPECA" },


@@ -287,7 +373,7 @@ static struct tok class2str[] = {
 };
 
 /* print a query */
 };
 
 /* print a query */

-static void
+static const u_char *

 ns_qprint(register const u_char *cp, register const u_char *bp)
 {
        register const u_char *np = cp;
 ns_qprint(register const u_char *cp, register const u_char *bp)
 {
        register const u_char *np = cp;


@@ -295,8 +381,8 @@ ns_qprint(register const u_char *cp, register const u_char *bp)
 
        cp = ns_nskip(cp, bp);
 
 
        cp = ns_nskip(cp, bp);
 

-       if (cp + 4 > snapend)
-               return;
+       if (cp + 4 > snapend || cp == NULL)
+               return(NULL);

 
        /* print the qtype and qclass (if it's not IN) */
        i = *cp++ << 8;
 
        /* print the qtype and qclass (if it's not IN) */
        i = *cp++ << 8;


@@ -308,7 +394,8 @@ ns_qprint(register const u_char *cp, register const u_char *bp)
                printf(" %s", tok2str(class2str, "(Class %d)", i));
 
        fputs("? ", stdout);
                printf(" %s", tok2str(class2str, "(Class %d)", i));
 
        fputs("? ", stdout);

-       ns_nprint(np, bp);
+       cp = ns_nprint(np, bp);
+       return(cp ? cp + 4 : NULL);

 }
 
 /* print a reply */
 }
 
 /* print a reply */


@@ -321,11 +408,12 @@ ns_rprint(register const u_char *cp, register const u_char *bp)
 
        if (vflag) {
                putchar(' ');
 
        if (vflag) {
                putchar(' ');

-               cp = ns_nprint(cp, bp);
+               if ((cp = ns_nprint(cp, bp)) == NULL)
+                       return NULL;

        } else
                cp = ns_nskip(cp, bp);
 
        } else
                cp = ns_nskip(cp, bp);
 

-       if (cp + 10 > snapend)
+       if (cp + 10 > snapend || cp == NULL)

                return (snapend);
 
        /* print the type/qtype and class (if it's not IN) */
                return (snapend);
 
        /* print the type/qtype and class (if it's not IN) */


@@ -345,9 +433,13 @@ ns_rprint(register const u_char *cp, register const u_char *bp)
        rp = cp + len;
 
        printf(" %s", tok2str(type2str, "Type%d", typ));
        rp = cp + len;
 
        printf(" %s", tok2str(type2str, "Type%d", typ));

-       switch (typ) {
+       if (rp > snapend)
+               return(NULL);

 
 

+       switch (typ) {

        case T_A:
        case T_A:

+               if (cp + sizeof(struct in_addr) > snapend)
+                       return(NULL);

                printf(" %s", ipaddr_string(cp));
                break;
 
                printf(" %s", ipaddr_string(cp));
                break;
 


@@ -355,15 +447,41 @@ ns_rprint(register const u_char *cp, register const u_char *bp)
        case T_CNAME:
        case T_PTR:
 #ifdef T_DNAME
        case T_CNAME:
        case T_PTR:
 #ifdef T_DNAME

-       case T_DNAME:   /*XXX not checked as there's no server support yet*/
+       case T_DNAME:

 #endif
                putchar(' ');
 #endif
                putchar(' ');

-               (void)ns_nprint(cp, bp);
+               if (ns_nprint(cp, bp) == NULL)
+                       return(NULL);

                break;
 
                break;
 

+       case T_SOA:
+               if (!vflag)
+                       break;
+               putchar(' ');
+               if ((cp = ns_nprint(cp, bp)) == NULL)
+                       return(NULL);
+               putchar(' ');
+               if ((cp = ns_nprint(cp, bp)) == NULL)
+                       return(NULL);
+               if (cp + 5 * 4 > snapend)
+                       return(NULL);
+               printf(" %u", EXTRACT_32BITS(cp));
+               cp += 4;
+               printf(" %u", EXTRACT_32BITS(cp));
+               cp += 4;
+               printf(" %u", EXTRACT_32BITS(cp));
+               cp += 4;
+               printf(" %u", EXTRACT_32BITS(cp));
+               cp += 4;
+               printf(" %u", EXTRACT_32BITS(cp));
+               cp += 4;
+               break;

        case T_MX:
                putchar(' ');
        case T_MX:
                putchar(' ');

-               (void)ns_nprint(cp + 2, bp);
+               if (cp + 2 > snapend)
+                       return(NULL);
+               if (ns_nprint(cp + 2, bp) == NULL)
+                       return(NULL);

                printf(" %d", EXTRACT_16BITS(cp));
                break;
 
                printf(" %d", EXTRACT_16BITS(cp));
                break;
 


@@ -374,25 +492,37 @@ ns_rprint(register const u_char *cp, register const u_char *bp)
 
 #ifdef INET6
        case T_AAAA:
 
 #ifdef INET6
        case T_AAAA:

+               if (cp + sizeof(struct in6_addr) > snapend)
+                       return(NULL);

                printf(" %s", ip6addr_string(cp));
                break;
 
                printf(" %s", ip6addr_string(cp));
                break;
 

-       case T_A6:      /*XXX not checked as there's no server support yet*/
+       case T_A6:

            {
                struct in6_addr a;
            {
                struct in6_addr a;

-               int pbyte;
-
-               pbyte = (*cp + 7) / 8;
-               memset(&a, 0, sizeof(a));
-               memcpy(&a.s6_addr[pbyte], cp + 1, sizeof(a) - pbyte);
-               printf(" %u %s ", *cp, ip6addr_string(&a));
-               (void)ns_nprint(cp + 1 + sizeof(a) - pbyte, bp);
+               int pbit, pbyte;
+
+               pbit = *cp;
+               pbyte = (pbit & ~7) / 8;
+               if (pbit > 128) {
+                       printf(" %u(bad plen)", pbit);
+                       break;
+               } else if (pbit < 128) {
+                       memset(&a, 0, sizeof(a));
+                       memcpy(&a.s6_addr[pbyte], cp + 1, sizeof(a) - pbyte);
+                       printf(" %u %s ", pbit, ip6addr_string(&a));
+               }
+               if (pbit > 0)
+                       if (ns_nprint(cp + 1 + sizeof(a) - pbyte, bp) == NULL)
+                               return(NULL);

                break;
            }
 #endif /*INET6*/
 
        case T_UNSPECA:         /* One long string */
                break;
            }
 #endif /*INET6*/
 
        case T_UNSPECA:         /* One long string */

-               printf(" %.*s", len, cp);
+               if (cp + len > snapend)
+                       return(NULL);
+               fn_printn(cp, len, snapend);

                break;
        }
        return (rp);            /* XXX This isn't always right */
                break;
        }
        return (rp);            /* XXX This isn't always right */


@@ -427,26 +557,55 @@ ns_print(register const u_char *bp, u_int length)
                        printf(" [%dq]", qdcount);
                /* Print QUESTION section on -vv */
                if (vflag > 1) {
                        printf(" [%dq]", qdcount);
                /* Print QUESTION section on -vv */
                if (vflag > 1) {

-                           fputs(" q: ", stdout);
-                           cp = ns_nprint((const u_char *)(np + 1), bp);
-               } else
-                           cp = ns_nskip((const u_char *)(np + 1), bp);
+                       fputs(" q:", stdout);
+                       if ((cp = ns_qprint((const u_char *)(np + 1), bp))
+                           == NULL)
+                               goto trunc;
+               } else {
+                       if ((cp = ns_nskip((const u_char *)(np + 1), bp))
+                           == NULL)
+                               goto trunc;
+                       cp += 4;
+               }

                printf(" %d/%d/%d", ancount, nscount, arcount);
                if (ancount--) {
                printf(" %d/%d/%d", ancount, nscount, arcount);
                if (ancount--) {

-                       cp = ns_rprint(cp + 4, bp);
+                       if ((cp = ns_rprint(cp, bp)) == NULL)
+                               goto trunc;

                        while (ancount-- && cp < snapend) {
                                putchar(',');
                        while (ancount-- && cp < snapend) {
                                putchar(',');

-                               cp = ns_rprint(cp, bp);
+                               if ((cp = ns_rprint(cp, bp)) == NULL)
+                                       goto trunc;
+                       }
+               }
+               /* Print NS and AR sections on -vv */
+               if (vflag > 1) {
+                       if (nscount-- && cp < snapend) {
+                               fputs(" ns:", stdout);
+                               if ((cp = ns_rprint(cp, bp)) == NULL)
+                                       goto trunc;
+                               while (nscount-- && cp < snapend) {
+                                       putchar(',');
+                                       if ((cp = ns_rprint(cp, bp)) == NULL)
+                                               goto trunc;
+                               }
+                       }
+                       if (arcount-- && cp < snapend) {
+                               fputs(" ar:", stdout);
+                               if ((cp = ns_rprint(cp, bp)) == NULL)
+                                       goto trunc;
+                               while (arcount-- && cp < snapend) {
+                                       putchar(',');
+                                       if ((cp = ns_rprint(cp, bp)) == NULL)
+                                               goto trunc;
+                               }

                        }
                }
        }
        else {
                /* this is a request */
                        }
                }
        }
        else {
                /* this is a request */

-               printf(" %d%s%s%s",
-                       ntohs(np->id),
-                       ns_ops[DNS_OPCODE(np)],
-                       DNS_RD(np)? "+" : "",
-                       DNS_AD(np)? "$" : "");
+               printf(" %d%s%s%s", ntohs(np->id), ns_ops[DNS_OPCODE(np)],
+                   DNS_RD(np) ? "+" : "",
+                   DNS_AD(np) ? "$" : "");

 
                /* any weirdness? */
                if (*(((u_short *)np)+1) & htons(0x6cf))
 
                /* any weirdness? */
                if (*(((u_short *)np)+1) & htons(0x6cf))


@@ -472,4 +631,9 @@ ns_print(register const u_char *bp, u_int length)
                ns_qprint((const u_char *)(np + 1), (const u_char *)np);
        }
        printf(" (%d)", length);
                ns_qprint((const u_char *)(np + 1), (const u_char *)np);
        }
        printf(" (%d)", length);

+       return;
+
+  trunc:
+       printf("[|domain]");
+       return;

 }
 }