contrib/bind-9.2.4rc7/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 1.1.2.3 2004/03/09 09:17:37 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 = msg + *msglen, *eob = msg + msgsize;
  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         /* Name. */
 104         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 105                 n = ns_name_pton(key->dk_key_name, name, sizeof name);
 106                 if (n != -1)
 107                         n = ns_name_pack(name, cp, eob - cp,
 108                                          (const u_char **)dnptrs,
 109                                          (const u_char **)lastdnptr);
 110
 111         } else {
 112                 n = ns_name_pton("", name, sizeof name);
 113                 if (n != -1)
 114                         n = ns_name_pack(name, cp, eob - cp, NULL, NULL);
 115         }
 116         if (n < 0)
 117                 return (NS_TSIG_ERROR_NO_SPACE);
 118         cp += n;
 119
 120         /* Type, class, ttl, length (not filled in yet). */
 121         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 122         PUTSHORT(ns_t_tsig, cp);
 123         PUTSHORT(ns_c_any, cp);
 124         PUTLONG(0, cp);         /* TTL */
 125         lenp = cp;
 126         cp += 2;
 127
 128         /* Alg. */
 129         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 130                 if (key->dk_alg != KEY_HMAC_MD5)
 131                         return (-ns_r_badkey);
 132                 n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
 133         }
 134         else
 135                 n = dn_comp("", cp, eob - cp, NULL, NULL);
 136         if (n < 0)
 137                 return (NS_TSIG_ERROR_NO_SPACE);
 138         alg = cp;
 139         cp += n;
 140
 141         /* Time. */
 142         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 143         PUTSHORT(0, cp);
 144         timesigned = time(NULL);
 145         if (error != ns_r_badtime)
 146                 PUTLONG(timesigned, cp);
 147         else
 148                 PUTLONG(in_timesigned, cp);
 149         PUTSHORT(NS_TSIG_FUDGE, cp);
 150
 151         /* Compute the signature. */
 152         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 153                 void *ctx;
 154                 u_char buf[NS_MAXCDNAME], *cp2;
 155                 int n;
 156
 157                 dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
 158
 159                 /* Digest the query signature, if this is a response. */
 160                 if (querysiglen > 0 && querysig != NULL) {
 161                         u_int16_t len_n = htons(querysiglen);
 162                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 163                                       (u_char *)&len_n, INT16SZ, NULL, 0);
 164                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 165                                       querysig, querysiglen, NULL, 0);
 166                 }
 167
 168                 /* Digest the message. */
 169                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
 170                               NULL, 0);
 171
 172                 /* Digest the key name. */
 173                 n = ns_name_ntol(name, buf, sizeof(buf));
 174                 INSIST(n > 0);
 175                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 176
 177                 /* Digest the class and TTL. */
 178                 cp2 = buf;
 179                 PUTSHORT(ns_c_any, cp2);
 180                 PUTLONG(0, cp2);
 181                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
 182                               NULL, 0);
 183
 184                 /* Digest the algorithm. */
 185                 n = ns_name_ntol(alg, buf, sizeof(buf));
 186                 INSIST(n > 0);
 187                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 188
 189                 /* Digest the time signed, fudge, error, and other data */
 190                 cp2 = buf;
 191                 PUTSHORT(0, cp2);       /* Top 16 bits of time */
 192                 if (error != ns_r_badtime)
 193                         PUTLONG(timesigned, cp2);
 194                 else
 195                         PUTLONG(in_timesigned, cp2);
 196                 PUTSHORT(NS_TSIG_FUDGE, cp2);
 197                 PUTSHORT(error, cp2);   /* Error */
 198                 if (error != ns_r_badtime)
 199                         PUTSHORT(0, cp2);       /* Other data length */
 200                 else {
 201                         PUTSHORT(INT16SZ+INT32SZ, cp2); /* Other data length */
 202                         PUTSHORT(0, cp2);       /* Top 16 bits of time */
 203                         PUTLONG(timesigned, cp2);
 204                 }
 205                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, cp2-buf,
 206                               NULL, 0);
 207
 208                 n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
 209                                   sig, *siglen);
 210                 if (n < 0)
 211                         return (-ns_r_badkey);
 212                 *siglen = n;
 213         } else
 214                 *siglen = 0;
 215
 216         /* Add the signature. */
 217         BOUNDS_CHECK(cp, INT16SZ + (*siglen));
 218         PUTSHORT(*siglen, cp);
 219         memcpy(cp, sig, *siglen);
 220         cp += (*siglen);
 221
 222         /* The original message ID & error. */
 223         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 224         PUTSHORT(ntohs(hp->id), cp);    /* already in network order */
 225         PUTSHORT(error, cp);
 226
 227         /* Other data. */
 228         BOUNDS_CHECK(cp, INT16SZ);
 229         if (error != ns_r_badtime)
 230                 PUTSHORT(0, cp);        /* Other data length */
 231         else {
 232                 PUTSHORT(INT16SZ+INT32SZ, cp);  /* Other data length */
 233                 BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
 234                 PUTSHORT(0, cp);        /* Top 16 bits of time */
 235                 PUTLONG(timesigned, cp);
 236         }
 237
 238         /* Go back and fill in the length. */
 239         PUTSHORT(cp - lenp - INT16SZ, lenp);
 240
 241         hp->arcount = htons(ntohs(hp->arcount) + 1);
 242         *msglen = (cp - msg);
 243         return (0);
 244 }
 245
 246 int
 247 ns_sign_tcp_init(void *k, const u_char *querysig, int querysiglen,
 248                  ns_tcp_tsig_state *state)
 249 {
 250         dst_init();
 251         if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
 252                 return (-1);
 253         state->counter = -1;
 254         state->key = k;
 255         if (state->key->dk_alg != KEY_HMAC_MD5)
 256                 return (-ns_r_badkey);
 257         if (querysiglen > (int)sizeof(state->sig))
 258                 return (-1);
 259         memcpy(state->sig, querysig, querysiglen);
 260         state->siglen = querysiglen;
 261         return (0);
 262 }
 263
 264 int
 265 ns_sign_tcp(u_char *msg, int *msglen, int msgsize, int error,
 266             ns_tcp_tsig_state *state, int done)
 267 {
 268         return (ns_sign_tcp2(msg, msglen, msgsize, error, state,
 269                              done, NULL, NULL));
 270 }
 271
 272 int
 273 ns_sign_tcp2(u_char *msg, int *msglen, int msgsize, int error,
 274              ns_tcp_tsig_state *state, int done,
 275              u_char **dnptrs, u_char **lastdnptr)
 276 {
 277         u_char *cp, *eob, *lenp;
 278         u_char buf[MAXDNAME], *cp2;
 279         HEADER *hp = (HEADER *)msg;
 280         time_t timesigned;
 281         int n;
 282
 283         if (msg == NULL || msglen == NULL || state == NULL)
 284                 return (-1);
 285
 286         state->counter++;
 287         if (state->counter == 0)
 288                 return (ns_sign2(msg, msglen, msgsize, error, state->key,
 289                                  state->sig, state->siglen,
 290                                  state->sig, &state->siglen, 0,
 291                                  dnptrs, lastdnptr));
 292
 293         if (state->siglen > 0) {
 294                 u_int16_t siglen_n = htons(state->siglen);
 295                 dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
 296                               NULL, 0, NULL, 0);
 297                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 298                               (u_char *)&siglen_n, INT16SZ, NULL, 0);
 299                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 300                               state->sig, state->siglen, NULL, 0);
 301                 state->siglen = 0;
 302         }
 303
 304         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
 305                       NULL, 0);
 306
 307         if (done == 0 && (state->counter % 100 != 0))
 308                 return (0);
 309
 310         cp = msg + *msglen;
 311         eob = msg + msgsize;
 312
 313         /* Name. */
 314         n = dn_comp(state->key->dk_key_name, cp, eob - cp, dnptrs, lastdnptr);
 315         if (n < 0)
 316                 return (NS_TSIG_ERROR_NO_SPACE);
 317         cp += n;
 318
 319         /* Type, class, ttl, length (not filled in yet). */
 320         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 321         PUTSHORT(ns_t_tsig, cp);
 322         PUTSHORT(ns_c_any, cp);
 323         PUTLONG(0, cp);         /* TTL */
 324         lenp = cp;
 325         cp += 2;
 326
 327         /* Alg. */
 328         n = dn_comp(NS_TSIG_ALG_HMAC_MD5, cp, eob - cp, NULL, NULL);
 329         if (n < 0)
 330                 return (NS_TSIG_ERROR_NO_SPACE);
 331         cp += n;
 332
 333         /* Time. */
 334         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 335         PUTSHORT(0, cp);
 336         timesigned = time(NULL);
 337         PUTLONG(timesigned, cp);
 338         PUTSHORT(NS_TSIG_FUDGE, cp);
 339
 340         /*
 341          * Compute the signature.
 342          */
 343
 344         /* Digest the time signed and fudge. */
 345         cp2 = buf;
 346         PUTSHORT(0, cp2);       /* Top 16 bits of time */
 347         PUTLONG(timesigned, cp2);
 348         PUTSHORT(NS_TSIG_FUDGE, cp2);
 349
 350         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 351                       buf, cp2 - buf, NULL, 0);
 352
 353         n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
 354                           state->sig, sizeof(state->sig));
 355         if (n < 0)
 356                 return (-ns_r_badkey);
 357         state->siglen = n;
 358
 359         /* Add the signature. */
 360         BOUNDS_CHECK(cp, INT16SZ + state->siglen);
 361         PUTSHORT(state->siglen, cp);
 362         memcpy(cp, state->sig, state->siglen);
 363         cp += state->siglen;
 364
 365         /* The original message ID & error. */
 366         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 367         PUTSHORT(ntohs(hp->id), cp);    /* already in network order */
 368         PUTSHORT(error, cp);
 369
 370         /* Other data. */
 371         BOUNDS_CHECK(cp, INT16SZ);
 372         PUTSHORT(0, cp);
 373
 374         /* Go back and fill in the length. */
 375         PUTSHORT(cp - lenp - INT16SZ, lenp);
 376
 377         hp->arcount = htons(ntohs(hp->arcount) + 1);
 378         *msglen = (cp - msg);
 379         return (0);
 380 }