contrib/bind-9.3/lib/bind/nameser/ns_sign.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1999 by Internet Software Consortium, Inc.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #ifndef lint
  19 static const char rcsid[] = "$Id: ns_sign.c,v 1.1.2.2.4.2 2006/03/10 00:17:21 marka Exp $";
  20 #endif
  21
  22 /* Import. */
  23
  24 #include "port_before.h"
  25 #include "fd_setsize.h"
  26
  27 #include <sys/types.h>
  28 #include <sys/param.h>
  29
  30 #include <netinet/in.h>
  31 #include <arpa/nameser.h>
  32 #include <arpa/inet.h>
  33
  34 #include <errno.h>
  35 #include <netdb.h>
  36 #include <resolv.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <time.h>
  41 #include <unistd.h>
  42
  43 #include <isc/dst.h>
  44 #include <isc/assertions.h>
  45
  46 #include "port_after.h"
  47
  48 #define BOUNDS_CHECK(ptr, count) \
  49         do { \
  50                 if ((ptr) + (count) > eob) { \
  51                         errno = EMSGSIZE; \
  52                         return(NS_TSIG_ERROR_NO_SPACE); \
  53                 } \
  54         } while (0)
  55
  56 /* ns_sign
  57  * Parameters:
  58  *      msg             message to be sent
  59  *      msglen          input - length of message
  60  *                      output - length of signed message
  61  *      msgsize         length of buffer containing message
  62  *      error           value to put in the error field
  63  *      key             tsig key used for signing
  64  *      querysig        (response), the signature in the query
  65  *      querysiglen     (response), the length of the signature in the query
  66  *      sig             a buffer to hold the generated signature
  67  *      siglen          input - length of signature buffer
  68  *                      output - length of signature
  69  *
  70  * Errors:
  71  *      - bad input data (-1)
  72  *      - bad key / sign failed (-BADKEY)
  73  *      - not enough space (NS_TSIG_ERROR_NO_SPACE)
  74  */
  75 int
  76 ns_sign(u_char *msg, int *msglen, int msgsize, int error, void *k,
  77         const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
  78         time_t in_timesigned)
  79 {
  80         return(ns_sign2(msg, msglen, msgsize, error, k,
  81                         querysig, querysiglen, sig, siglen,
  82                         in_timesigned, NULL, NULL));
  83 }
  84
  85 int
  86 ns_sign2(u_char *msg, int *msglen, int msgsize, int error, void *k,
  87          const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
  88          time_t in_timesigned, u_char **dnptrs, u_char **lastdnptr)
  89 {
  90         HEADER *hp = (HEADER *)msg;
  91         DST_KEY *key = (DST_KEY *)k;
  92         u_char *cp, *eob;
  93         u_char *lenp;
  94         u_char *alg;
  95         int n;
  96         time_t timesigned;
  97         u_char name[NS_MAXCDNAME];
  98
  99         dst_init();
 100         if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
 101                 return (-1);
 102
 103         cp = msg + *msglen;
 104         eob = msg + msgsize;
 105
 106         /* Name. */
 107         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 108                 n = ns_name_pton(key->dk_key_name, name, sizeof name);
 109                 if (n != -1)
 110                         n = ns_name_pack(name, cp, eob - cp,
 111                                          (const u_char **)dnptrs,
 112                                          (const u_char **)lastdnptr);
 113
 114         } else {
 115                 n = ns_name_pton("", name, sizeof name);
 116                 if (n != -1)
 117                         n = ns_name_pack(name, cp, eob - cp, NULL, NULL);
 118         }
 119         if (n < 0)
 120                 return (NS_TSIG_ERROR_NO_SPACE);
 121         cp += n;
 122
 123         /* Type, class, ttl, length (not filled in yet). */
 124         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 125         PUTSHORT(ns_t_tsig, cp);
 126         PUTSHORT(ns_c_any, cp);
 127         PUTLONG(0, cp);         /* TTL */
 128         lenp = cp;
 129         cp += 2;
 130
 131         /* Alg. */
 132         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 133                 if (key->dk_alg != KEY_HMAC_MD5)
 134                         return (-ns_r_badkey);
 135                 n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
 136         }
 137         else
 138                 n = dn_comp("", cp, eob - cp, NULL, NULL);
 139         if (n < 0)
 140                 return (NS_TSIG_ERROR_NO_SPACE);
 141         alg = cp;
 142         cp += n;
 143
 144         /* Time. */
 145         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 146         PUTSHORT(0, cp);
 147         timesigned = time(NULL);
 148         if (error != ns_r_badtime)
 149                 PUTLONG(timesigned, cp);
 150         else
 151                 PUTLONG(in_timesigned, cp);
 152         PUTSHORT(NS_TSIG_FUDGE, cp);
 153
 154         /* Compute the signature. */
 155         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 156                 void *ctx;
 157                 u_char buf[NS_MAXCDNAME], *cp2;
 158                 int n;
 159
 160                 dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
 161
 162                 /* Digest the query signature, if this is a response. */
 163                 if (querysiglen > 0 && querysig != NULL) {
 164                         u_int16_t len_n = htons(querysiglen);
 165                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 166                                       (u_char *)&len_n, INT16SZ, NULL, 0);
 167                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 168                                       querysig, querysiglen, NULL, 0);
 169                 }
 170
 171                 /* Digest the message. */
 172                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
 173                               NULL, 0);
 174
 175                 /* Digest the key name. */
 176                 n = ns_name_ntol(name, buf, sizeof(buf));
 177                 INSIST(n > 0);
 178                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 179
 180                 /* Digest the class and TTL. */
 181                 cp2 = buf;
 182                 PUTSHORT(ns_c_any, cp2);
 183                 PUTLONG(0, cp2);
 184                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
 185                               NULL, 0);
 186
 187                 /* Digest the algorithm. */
 188                 n = ns_name_ntol(alg, buf, sizeof(buf));
 189                 INSIST(n > 0);
 190                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 191
 192                 /* Digest the time signed, fudge, error, and other data */
 193                 cp2 = buf;
 194                 PUTSHORT(0, cp2);       /* Top 16 bits of time */
 195                 if (error != ns_r_badtime)
 196                         PUTLONG(timesigned, cp2);
 197                 else
 198                         PUTLONG(in_timesigned, cp2);
 199                 PUTSHORT(NS_TSIG_FUDGE, cp2);
 200                 PUTSHORT(error, cp2);   /* Error */
 201                 if (error != ns_r_badtime)
 202                         PUTSHORT(0, cp2);       /* Other data length */
 203                 else {
 204                         PUTSHORT(INT16SZ+INT32SZ, cp2); /* Other data length */
 205                         PUTSHORT(0, cp2);       /* Top 16 bits of time */
 206                         PUTLONG(timesigned, cp2);
 207                 }
 208                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
 209                               NULL, 0);
 210
 211                 n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
 212                                   sig, *siglen);
 213                 if (n < 0)
 214                         return (-ns_r_badkey);
 215                 *siglen = n;
 216         } else
 217                 *siglen = 0;
 218
 219         /* Add the signature. */
 220         BOUNDS_CHECK(cp, INT16SZ + (*siglen));
 221         PUTSHORT(*siglen, cp);
 222         memcpy(cp, sig, *siglen);
 223         cp += (*siglen);
 224
 225         /* The original message ID & error. */
 226         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 227         PUTSHORT(ntohs(hp->id), cp);    /* already in network order */
 228         PUTSHORT(error, cp);
 229
 230         /* Other data. */
 231         BOUNDS_CHECK(cp, INT16SZ);
 232         if (error != ns_r_badtime)
 233                 PUTSHORT(0, cp);        /* Other data length */
 234         else {
 235                 PUTSHORT(INT16SZ+INT32SZ, cp);  /* Other data length */
 236                 BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
 237                 PUTSHORT(0, cp);        /* Top 16 bits of time */
 238                 PUTLONG(timesigned, cp);
 239         }
 240
 241         /* Go back and fill in the length. */
 242         PUTSHORT(cp - lenp - INT16SZ, lenp);
 243
 244         hp->arcount = htons(ntohs(hp->arcount) + 1);
 245         *msglen = (cp - msg);
 246         return (0);
 247 }
 248
 249 int
 250 ns_sign_tcp_init(void *k, const u_char *querysig, int querysiglen,
 251                  ns_tcp_tsig_state *state)
 252 {
 253         dst_init();
 254         if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
 255                 return (-1);
 256         state->counter = -1;
 257         state->key = k;
 258         if (state->key->dk_alg != KEY_HMAC_MD5)
 259                 return (-ns_r_badkey);
 260         if (querysiglen > (int)sizeof(state->sig))
 261                 return (-1);
 262         memcpy(state->sig, querysig, querysiglen);
 263         state->siglen = querysiglen;
 264         return (0);
 265 }
 266
 267 int
 268 ns_sign_tcp(u_char *msg, int *msglen, int msgsize, int error,
 269             ns_tcp_tsig_state *state, int done)
 270 {
 271         return (ns_sign_tcp2(msg, msglen, msgsize, error, state,
 272                              done, NULL, NULL));
 273 }
 274
 275 int
 276 ns_sign_tcp2(u_char *msg, int *msglen, int msgsize, int error,
 277              ns_tcp_tsig_state *state, int done,
 278              u_char **dnptrs, u_char **lastdnptr)
 279 {
 280         u_char *cp, *eob, *lenp;
 281         u_char buf[MAXDNAME], *cp2;
 282         HEADER *hp = (HEADER *)msg;
 283         time_t timesigned;
 284         int n;
 285
 286         if (msg == NULL || msglen == NULL || state == NULL)
 287                 return (-1);
 288
 289         state->counter++;
 290         if (state->counter == 0)
 291                 return (ns_sign2(msg, msglen, msgsize, error, state->key,
 292                                  state->sig, state->siglen,
 293                                  state->sig, &state->siglen, 0,
 294                                  dnptrs, lastdnptr));
 295
 296         if (state->siglen > 0) {
 297                 u_int16_t siglen_n = htons(state->siglen);
 298                 dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
 299                               NULL, 0, NULL, 0);
 300                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 301                               (u_char *)&siglen_n, INT16SZ, NULL, 0);
 302                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 303                               state->sig, state->siglen, NULL, 0);
 304                 state->siglen = 0;
 305         }
 306
 307         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
 308                       NULL, 0);
 309
 310         if (done == 0 && (state->counter % 100 != 0))
 311                 return (0);
 312
 313         cp = msg + *msglen;
 314         eob = msg + msgsize;
 315
 316         /* Name. */
 317         n = dn_comp(state->key->dk_key_name, cp, eob - cp, dnptrs, lastdnptr);
 318         if (n < 0)
 319                 return (NS_TSIG_ERROR_NO_SPACE);
 320         cp += n;
 321
 322         /* Type, class, ttl, length (not filled in yet). */
 323         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 324         PUTSHORT(ns_t_tsig, cp);
 325         PUTSHORT(ns_c_any, cp);
 326         PUTLONG(0, cp);         /* TTL */
 327         lenp = cp;
 328         cp += 2;
 329
 330         /* Alg. */
 331         n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
 332         if (n < 0)
 333                 return (NS_TSIG_ERROR_NO_SPACE);
 334         cp += n;
 335
 336         /* Time. */
 337         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 338         PUTSHORT(0, cp);
 339         timesigned = time(NULL);
 340         PUTLONG(timesigned, cp);
 341         PUTSHORT(NS_TSIG_FUDGE, cp);
 342
 343         /*
 344          * Compute the signature.
 345          */
 346
 347         /* Digest the time signed and fudge. */
 348         cp2 = buf;
 349         PUTSHORT(0, cp2);       /* Top 16 bits of time */
 350         PUTLONG(timesigned, cp2);
 351         PUTSHORT(NS_TSIG_FUDGE, cp2);
 352
 353         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 354                       buf, cp2 - buf, NULL, 0);
 355
 356         n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
 357                           state->sig, sizeof(state->sig));
 358         if (n < 0)
 359                 return (-ns_r_badkey);
 360         state->siglen = n;
 361
 362         /* Add the signature. */
 363         BOUNDS_CHECK(cp, INT16SZ + state->siglen);
 364         PUTSHORT(state->siglen, cp);
 365         memcpy(cp, state->sig, state->siglen);
 366         cp += state->siglen;
 367
 368         /* The original message ID & error. */
 369         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 370         PUTSHORT(ntohs(hp->id), cp);    /* already in network order */
 371         PUTSHORT(error, cp);
 372
 373         /* Other data. */
 374         BOUNDS_CHECK(cp, INT16SZ);
 375         PUTSHORT(0, cp);
 376
 377         /* Go back and fill in the length. */
 378         PUTSHORT(cp - lenp - INT16SZ, lenp);
 379
 380         hp->arcount = htons(ntohs(hp->arcount) + 1);
 381         *msglen = (cp - msg);
 382         return (0);
 383 }