contrib/bind-9.5.2/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 1.6 2006/03/09 23:57:56 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 /*%
  57  *  ns_sign
  58  *
  59  * Parameters:
  60  *\li   msg             message to be sent
  61  *\li   msglen          input - length of message
  62  *                      output - length of signed message
  63  *\li   msgsize         length of buffer containing message
  64  *\li   error           value to put in the error field
  65  *\li   key             tsig key used for signing
  66  *\li   querysig        (response), the signature in the query
  67  *\li   querysiglen     (response), the length of the signature in the query
  68  *\li   sig             a buffer to hold the generated signature
  69  *\li   siglen          input - length of signature buffer
  70  *                      output - length of signature
  71  *
  72  * Errors:
  73  *\li   - bad input data (-1)
  74  *\li   - bad key / sign failed (-BADKEY)
  75  *\li   - not enough space (NS_TSIG_ERROR_NO_SPACE)
  76  */
  77 int
  78 ns_sign(u_char *msg, int *msglen, int msgsize, int error, void *k,
  79         const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
  80         time_t in_timesigned)
  81 {
  82         return(ns_sign2(msg, msglen, msgsize, error, k,
  83                         querysig, querysiglen, sig, siglen,
  84                         in_timesigned, NULL, NULL));
  85 }
  86
  87 int
  88 ns_sign2(u_char *msg, int *msglen, int msgsize, int error, void *k,
  89          const u_char *querysig, int querysiglen, u_char *sig, int *siglen,
  90          time_t in_timesigned, u_char **dnptrs, u_char **lastdnptr)
  91 {
  92         HEADER *hp = (HEADER *)msg;
  93         DST_KEY *key = (DST_KEY *)k;
  94         u_char *cp, *eob;
  95         u_char *lenp;
  96         u_char *alg;
  97         int n;
  98         time_t timesigned;
  99         u_char name[NS_MAXCDNAME];
 100
 101         dst_init();
 102         if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
 103                 return (-1);
 104
 105         cp = msg + *msglen;
 106         eob = msg + msgsize;
 107
 108         /* Name. */
 109         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 110                 n = ns_name_pton(key->dk_key_name, name, sizeof name);
 111                 if (n != -1)
 112                         n = ns_name_pack(name, cp, eob - cp,
 113                                          (const u_char **)dnptrs,
 114                                          (const u_char **)lastdnptr);
 115
 116         } else {
 117                 n = ns_name_pton("", name, sizeof name);
 118                 if (n != -1)
 119                         n = ns_name_pack(name, cp, eob - cp, NULL, NULL);
 120         }
 121         if (n < 0)
 122                 return (NS_TSIG_ERROR_NO_SPACE);
 123         cp += n;
 124
 125         /* Type, class, ttl, length (not filled in yet). */
 126         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 127         PUTSHORT(ns_t_tsig, cp);
 128         PUTSHORT(ns_c_any, cp);
 129         PUTLONG(0, cp);         /*%< TTL */
 130         lenp = cp;
 131         cp += 2;
 132
 133         /* Alg. */
 134         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 135                 if (key->dk_alg != KEY_HMAC_MD5)
 136                         return (-ns_r_badkey);
 137                 n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
 138         }
 139         else
 140                 n = dn_comp("", cp, eob - cp, NULL, NULL);
 141         if (n < 0)
 142                 return (NS_TSIG_ERROR_NO_SPACE);
 143         alg = cp;
 144         cp += n;
 145
 146         /* Time. */
 147         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 148         PUTSHORT(0, cp);
 149         timesigned = time(NULL);
 150         if (error != ns_r_badtime)
 151                 PUTLONG(timesigned, cp);
 152         else
 153                 PUTLONG(in_timesigned, cp);
 154         PUTSHORT(NS_TSIG_FUDGE, cp);
 155
 156         /* Compute the signature. */
 157         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 158                 void *ctx;
 159                 u_char buf[NS_MAXCDNAME], *cp2;
 160                 int n;
 161
 162                 dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
 163
 164                 /* Digest the query signature, if this is a response. */
 165                 if (querysiglen > 0 && querysig != NULL) {
 166                         u_int16_t len_n = htons(querysiglen);
 167                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 168                                       (u_char *)&len_n, INT16SZ, NULL, 0);
 169                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 170                                       querysig, querysiglen, NULL, 0);
 171                 }
 172
 173                 /* Digest the message. */
 174                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
 175                               NULL, 0);
 176
 177                 /* Digest the key name. */
 178                 n = ns_name_ntol(name, buf, sizeof(buf));
 179                 INSIST(n > 0);
 180                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 181
 182                 /* Digest the class and TTL. */
 183                 cp2 = buf;
 184                 PUTSHORT(ns_c_any, cp2);
 185                 PUTLONG(0, cp2);
 186                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
 187                               NULL, 0);
 188
 189                 /* Digest the algorithm. */
 190                 n = ns_name_ntol(alg, buf, sizeof(buf));
 191                 INSIST(n > 0);
 192                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 193
 194                 /* Digest the time signed, fudge, error, and other data */
 195                 cp2 = buf;
 196                 PUTSHORT(0, cp2);       /*%< Top 16 bits of time */
 197                 if (error != ns_r_badtime)
 198                         PUTLONG(timesigned, cp2);
 199                 else
 200                         PUTLONG(in_timesigned, cp2);
 201                 PUTSHORT(NS_TSIG_FUDGE, cp2);
 202                 PUTSHORT(error, cp2);   /*%< Error */
 203                 if (error != ns_r_badtime)
 204                         PUTSHORT(0, cp2);       /*%< Other data length */
 205                 else {
 206                         PUTSHORT(INT16SZ+INT32SZ, cp2); /*%< Other data length */
 207                         PUTSHORT(0, cp2);       /*%< Top 16 bits of time */
 208                         PUTLONG(timesigned, cp2);
 209                 }
 210                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
 211                               NULL, 0);
 212
 213                 n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
 214                                   sig, *siglen);
 215                 if (n < 0)
 216                         return (-ns_r_badkey);
 217                 *siglen = n;
 218         } else
 219                 *siglen = 0;
 220
 221         /* Add the signature. */
 222         BOUNDS_CHECK(cp, INT16SZ + (*siglen));
 223         PUTSHORT(*siglen, cp);
 224         memcpy(cp, sig, *siglen);
 225         cp += (*siglen);
 226
 227         /* The original message ID & error. */
 228         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 229         PUTSHORT(ntohs(hp->id), cp);    /*%< already in network order */
 230         PUTSHORT(error, cp);
 231
 232         /* Other data. */
 233         BOUNDS_CHECK(cp, INT16SZ);
 234         if (error != ns_r_badtime)
 235                 PUTSHORT(0, cp);        /*%< Other data length */
 236         else {
 237                 PUTSHORT(INT16SZ+INT32SZ, cp);  /*%< Other data length */
 238                 BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
 239                 PUTSHORT(0, cp);        /*%< Top 16 bits of time */
 240                 PUTLONG(timesigned, cp);
 241         }
 242
 243         /* Go back and fill in the length. */
 244         PUTSHORT(cp - lenp - INT16SZ, lenp);
 245
 246         hp->arcount = htons(ntohs(hp->arcount) + 1);
 247         *msglen = (cp - msg);
 248         return (0);
 249 }
 250
 251 int
 252 ns_sign_tcp_init(void *k, const u_char *querysig, int querysiglen,
 253                  ns_tcp_tsig_state *state)
 254 {
 255         dst_init();
 256         if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
 257                 return (-1);
 258         state->counter = -1;
 259         state->key = k;
 260         if (state->key->dk_alg != KEY_HMAC_MD5)
 261                 return (-ns_r_badkey);
 262         if (querysiglen > (int)sizeof(state->sig))
 263                 return (-1);
 264         memcpy(state->sig, querysig, querysiglen);
 265         state->siglen = querysiglen;
 266         return (0);
 267 }
 268
 269 int
 270 ns_sign_tcp(u_char *msg, int *msglen, int msgsize, int error,
 271             ns_tcp_tsig_state *state, int done)
 272 {
 273         return (ns_sign_tcp2(msg, msglen, msgsize, error, state,
 274                              done, NULL, NULL));
 275 }
 276
 277 int
 278 ns_sign_tcp2(u_char *msg, int *msglen, int msgsize, int error,
 279              ns_tcp_tsig_state *state, int done,
 280              u_char **dnptrs, u_char **lastdnptr)
 281 {
 282         u_char *cp, *eob, *lenp;
 283         u_char buf[MAXDNAME], *cp2;
 284         HEADER *hp = (HEADER *)msg;
 285         time_t timesigned;
 286         int n;
 287
 288         if (msg == NULL || msglen == NULL || state == NULL)
 289                 return (-1);
 290
 291         state->counter++;
 292         if (state->counter == 0)
 293                 return (ns_sign2(msg, msglen, msgsize, error, state->key,
 294                                  state->sig, state->siglen,
 295                                  state->sig, &state->siglen, 0,
 296                                  dnptrs, lastdnptr));
 297
 298         if (state->siglen > 0) {
 299                 u_int16_t siglen_n = htons(state->siglen);
 300                 dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
 301                               NULL, 0, NULL, 0);
 302                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 303                               (u_char *)&siglen_n, INT16SZ, NULL, 0);
 304                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 305                               state->sig, state->siglen, NULL, 0);
 306                 state->siglen = 0;
 307         }
 308
 309         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
 310                       NULL, 0);
 311
 312         if (done == 0 && (state->counter % 100 != 0))
 313                 return (0);
 314
 315         cp = msg + *msglen;
 316         eob = msg + msgsize;
 317
 318         /* Name. */
 319         n = dn_comp(state->key->dk_key_name, cp, eob - cp, dnptrs, lastdnptr);
 320         if (n < 0)
 321                 return (NS_TSIG_ERROR_NO_SPACE);
 322         cp += n;
 323
 324         /* Type, class, ttl, length (not filled in yet). */
 325         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 326         PUTSHORT(ns_t_tsig, cp);
 327         PUTSHORT(ns_c_any, cp);
 328         PUTLONG(0, cp);         /*%< TTL */
 329         lenp = cp;
 330         cp += 2;
 331
 332         /* Alg. */
 333         n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
 334         if (n < 0)
 335                 return (NS_TSIG_ERROR_NO_SPACE);
 336         cp += n;
 337
 338         /* Time. */
 339         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 340         PUTSHORT(0, cp);
 341         timesigned = time(NULL);
 342         PUTLONG(timesigned, cp);
 343         PUTSHORT(NS_TSIG_FUDGE, cp);
 344
 345         /*
 346          * Compute the signature.
 347          */
 348
 349         /* Digest the time signed and fudge. */
 350         cp2 = buf;
 351         PUTSHORT(0, cp2);       /*%< Top 16 bits of time */
 352         PUTLONG(timesigned, cp2);
 353         PUTSHORT(NS_TSIG_FUDGE, cp2);
 354
 355         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 356                       buf, cp2 - buf, NULL, 0);
 357
 358         n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
 359                           state->sig, sizeof(state->sig));
 360         if (n < 0)
 361                 return (-ns_r_badkey);
 362         state->siglen = n;
 363
 364         /* Add the signature. */
 365         BOUNDS_CHECK(cp, INT16SZ + state->siglen);
 366         PUTSHORT(state->siglen, cp);
 367         memcpy(cp, state->sig, state->siglen);
 368         cp += state->siglen;
 369
 370         /* The original message ID & error. */
 371         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 372         PUTSHORT(ntohs(hp->id), cp);    /*%< already in network order */
 373         PUTSHORT(error, cp);
 374
 375         /* Other data. */
 376         BOUNDS_CHECK(cp, INT16SZ);
 377         PUTSHORT(0, cp);
 378
 379         /* Go back and fill in the length. */
 380         PUTSHORT(cp - lenp - INT16SZ, lenp);
 381
 382         hp->arcount = htons(ntohs(hp->arcount) + 1);
 383         *msglen = (cp - msg);
 384         return (0);
 385 }
 386
 387 /*! \file */