contrib/dhcp-3.0/minires/ns_sign.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1999-2003 by Internet Software Consortium
   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  *   Internet Systems Consortium, Inc.
  18  *   950 Charter Street
  19  *   Redwood City, CA 94063
  20  *   <info@isc.org>
  21  *   http://www.isc.org/
  22  */
  23
  24 #ifndef lint
  25 static const char rcsid[] = "$Id: ns_sign.c,v 1.4.2.4 2004/06/10 17:59:42 dhankins Exp $";
  26 #endif
  27
  28 #if defined (TRACING)
  29 #define time(x)         trace_mr_time (x)
  30 time_t trace_mr_time (time_t *);
  31 #endif
  32
  33 /* Import. */
  34
  35 #include <sys/types.h>
  36 #include <sys/param.h>
  37
  38 #include <netinet/in.h>
  39 #include <arpa/inet.h>
  40 #include <sys/socket.h>
  41
  42 #include <errno.h>
  43 #include <netdb.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48 #include <time.h>
  49
  50 #include "minires/minires.h"
  51 #include "arpa/nameser.h"
  52
  53 #include <isc-dhcp/dst.h>
  54
  55 #define BOUNDS_CHECK(ptr, count) \
  56         do { \
  57                 if ((ptr) + (count) > eob) { \
  58                         return ISC_R_NOSPACE; \
  59                 } \
  60         } while (0)
  61
  62 /* ns_sign
  63  * Parameters:
  64  *      msg             message to be sent
  65  *      msglen          input - length of message
  66  *                      output - length of signed message
  67  *      msgsize         length of buffer containing message
  68  *      error           value to put in the error field
  69  *      key             tsig key used for signing
  70  *      querysig        (response), the signature in the query
  71  *      querysiglen     (response), the length of the signature in the query
  72  *      sig             a buffer to hold the generated signature
  73  *      siglen          input - length of signature buffer
  74  *                      output - length of signature
  75  *
  76  * Errors:
  77  *      - bad input data (-1)
  78  *      - bad key / sign failed (-BADKEY)
  79  *      - not enough space (NS_TSIG_ERROR_NO_SPACE)
  80  */
  81 isc_result_t
  82 ns_sign(u_char *msg, unsigned *msglen, unsigned msgsize, int error, void *k,
  83         const u_char *querysig, unsigned querysiglen, u_char *sig,
  84         unsigned *siglen, time_t in_timesigned)
  85 {
  86         HEADER *hp = (HEADER *)msg;
  87         DST_KEY *key = (DST_KEY *)k;
  88         u_char *cp = msg + *msglen, *eob = msg + msgsize;
  89         u_char *lenp;
  90         u_char *name, *alg;
  91         unsigned n;
  92         time_t timesigned;
  93
  94         dst_init();
  95         if (msg == NULL || msglen == NULL || sig == NULL || siglen == NULL)
  96                 return ISC_R_INVALIDARG;
  97
  98         /* Name. */
  99         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey)
 100                 n = dn_comp(key->dk_key_name,
 101                             cp, (unsigned)(eob - cp), NULL, NULL);
 102         else
 103                 n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
 104         if (n < 0)
 105                 return ISC_R_NOSPACE;
 106         name = cp;
 107         cp += n;
 108
 109         /* Type, class, ttl, length (not filled in yet). */
 110         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 111         PUTSHORT(ns_t_tsig, cp);
 112         PUTSHORT(ns_c_any, cp);
 113         PUTLONG(0, cp);         /* TTL */
 114         lenp = cp;
 115         cp += 2;
 116
 117         /* Alg. */
 118         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 119                 if (key->dk_alg != KEY_HMAC_MD5)
 120                         return ISC_R_BADKEY;
 121                 n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
 122                             cp, (unsigned)(eob - cp), NULL, NULL);
 123         }
 124         else
 125                 n = dn_comp("", cp, (unsigned)(eob - cp), NULL, NULL);
 126         if (n < 0)
 127                 return ISC_R_NOSPACE;
 128         alg = cp;
 129         cp += n;
 130
 131         /* Time. */
 132         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 133         PUTSHORT(0, cp);
 134         timesigned = time(NULL);
 135         if (error != ns_r_badtime)
 136                 PUTLONG(timesigned, cp);
 137         else
 138                 PUTLONG(in_timesigned, cp);
 139         PUTSHORT(NS_TSIG_FUDGE, cp);
 140
 141         /* Compute the signature. */
 142         if (key != NULL && error != ns_r_badsig && error != ns_r_badkey) {
 143                 void *ctx;
 144                 u_char buf[MAXDNAME], *cp2;
 145                 unsigned n;
 146
 147                 dst_sign_data(SIG_MODE_INIT, key, &ctx, NULL, 0, NULL, 0);
 148
 149                 /* Digest the query signature, if this is a response. */
 150                 if (querysiglen > 0 && querysig != NULL) {
 151                         u_int16_t len_n = htons(querysiglen);
 152                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 153                                       (u_char *)&len_n, INT16SZ, NULL, 0);
 154                         dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 155                                       querysig, querysiglen, NULL, 0);
 156                 }
 157
 158                 /* Digest the message. */
 159                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, msg, *msglen,
 160                               NULL, 0);
 161
 162                 /* Digest the key name. */
 163                 n = ns_name_ntol(name, buf, sizeof(buf));
 164                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 165
 166                 /* Digest the class and TTL. */
 167                 cp2 = buf;
 168                 PUTSHORT(ns_c_any, cp2);
 169                 PUTLONG(0, cp2);
 170                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 171                               buf, (unsigned)(cp2-buf), NULL, 0);
 172
 173                 /* Digest the algorithm. */
 174                 n = ns_name_ntol(alg, buf, sizeof(buf));
 175                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx, buf, n, NULL, 0);
 176
 177                 /* Digest the time signed, fudge, error, and other data */
 178                 cp2 = buf;
 179                 PUTSHORT(0, cp2);       /* Top 16 bits of time */
 180                 if (error != ns_r_badtime)
 181                         PUTLONG(timesigned, cp2);
 182                 else
 183                         PUTLONG(in_timesigned, cp2);
 184                 PUTSHORT(NS_TSIG_FUDGE, cp2);
 185                 PUTSHORT(error, cp2);   /* Error */
 186                 if (error != ns_r_badtime)
 187                         PUTSHORT(0, cp2);       /* Other data length */
 188                 else {
 189                         PUTSHORT(INT16SZ+INT32SZ, cp2); /* Other data length */
 190                         PUTSHORT(0, cp2);       /* Top 16 bits of time */
 191                         PUTLONG(timesigned, cp2);
 192                 }
 193                 dst_sign_data(SIG_MODE_UPDATE, key, &ctx,
 194                               buf, (unsigned)(cp2-buf), NULL, 0);
 195
 196                 n = dst_sign_data(SIG_MODE_FINAL, key, &ctx, NULL, 0,
 197                                   sig, *siglen);
 198                 if (n < 0)
 199                         return ISC_R_BADKEY;
 200                 *siglen = n;
 201         } else
 202                 *siglen = 0;
 203
 204         /* Add the signature. */
 205         BOUNDS_CHECK(cp, INT16SZ + (*siglen));
 206         PUTSHORT(*siglen, cp);
 207         memcpy(cp, sig, *siglen);
 208         cp += (*siglen);
 209
 210         /* The original message ID & error. */
 211         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 212         PUTSHORT(ntohs(hp->id), cp);    /* already in network order */
 213         PUTSHORT(error, cp);
 214
 215         /* Other data. */
 216         BOUNDS_CHECK(cp, INT16SZ);
 217         if (error != ns_r_badtime)
 218                 PUTSHORT(0, cp);        /* Other data length */
 219         else {
 220                 PUTSHORT(INT16SZ+INT32SZ, cp);  /* Other data length */
 221                 BOUNDS_CHECK(cp, INT32SZ+INT16SZ);
 222                 PUTSHORT(0, cp);        /* Top 16 bits of time */
 223                 PUTLONG(timesigned, cp);
 224         }
 225
 226         /* Go back and fill in the length. */
 227         PUTSHORT(cp - lenp - INT16SZ, lenp);
 228
 229         hp->arcount = htons(ntohs(hp->arcount) + 1);
 230         *msglen = (cp - msg);
 231         return ISC_R_SUCCESS;
 232 }
 233
 234 #if 0
 235 isc_result_t
 236 ns_sign_tcp_init(void *k, const u_char *querysig, unsigned querysiglen,
 237                  ns_tcp_tsig_state *state)
 238 {
 239         dst_init();
 240         if (state == NULL || k == NULL || querysig == NULL || querysiglen < 0)
 241                 return ISC_R_INVALIDARG;
 242         state->counter = -1;
 243         state->key = k;
 244         if (state->key->dk_alg != KEY_HMAC_MD5)
 245                 return ISC_R_BADKEY;
 246         if (querysiglen > sizeof(state->sig))
 247                 return ISC_R_NOSPACE;
 248         memcpy(state->sig, querysig, querysiglen);
 249         state->siglen = querysiglen;
 250         return ISC_R_SUCCESS;
 251 }
 252
 253 isc_result_t
 254 ns_sign_tcp(u_char *msg, unsigned *msglen, unsigned msgsize, int error,
 255             ns_tcp_tsig_state *state, int done)
 256 {
 257         u_char *cp, *eob, *lenp;
 258         u_char buf[MAXDNAME], *cp2;
 259         HEADER *hp = (HEADER *)msg;
 260         time_t timesigned;
 261         int n;
 262
 263         if (msg == NULL || msglen == NULL || state == NULL)
 264                 return ISC_R_INVALIDARG;
 265
 266         state->counter++;
 267         if (state->counter == 0)
 268                 return ns_sign(msg, msglen, msgsize, error, state->key,
 269                                state->sig, state->siglen,
 270                                state->sig, &state->siglen, 0);
 271
 272         if (state->siglen > 0) {
 273                 u_int16_t siglen_n = htons(state->siglen);
 274                 dst_sign_data(SIG_MODE_INIT, state->key, &state->ctx,
 275                               NULL, 0, NULL, 0);
 276                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 277                               (u_char *)&siglen_n, INT16SZ, NULL, 0);
 278                 dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 279                               state->sig, state->siglen, NULL, 0);
 280                 state->siglen = 0;
 281         }
 282
 283         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx, msg, *msglen,
 284                       NULL, 0);
 285
 286         if (done == 0 && (state->counter % 100 != 0))
 287                 return ISC_R_SUCCESS;
 288
 289         cp = msg + *msglen;
 290         eob = msg + msgsize;
 291
 292         /* Name. */
 293         n = dn_comp(state->key->dk_key_name,
 294                     cp, (unsigned)(eob - cp), NULL, NULL);
 295         if (n < 0)
 296                 return ISC_R_NOSPACE;
 297         cp += n;
 298
 299         /* Type, class, ttl, length (not filled in yet). */
 300         BOUNDS_CHECK(cp, INT16SZ + INT16SZ + INT32SZ + INT16SZ);
 301         PUTSHORT(ns_t_tsig, cp);
 302         PUTSHORT(ns_c_any, cp);
 303         PUTLONG(0, cp);         /* TTL */
 304         lenp = cp;
 305         cp += 2;
 306
 307         /* Alg. */
 308         n = dn_comp(NS_TSIG_ALG_HMAC_MD5,
 309                     cp, (unsigned)(eob - cp), NULL, NULL);
 310         if (n < 0)
 311                 return ISC_R_NOSPACE;
 312         cp += n;
 313
 314         /* Time. */
 315         BOUNDS_CHECK(cp, INT16SZ + INT32SZ + INT16SZ);
 316         PUTSHORT(0, cp);
 317         timesigned = time(NULL);
 318         PUTLONG(timesigned, cp);
 319         PUTSHORT(NS_TSIG_FUDGE, cp);
 320
 321         /*
 322          * Compute the signature.
 323          */
 324
 325         /* Digest the time signed and fudge. */
 326         cp2 = buf;
 327         PUTSHORT(0, cp2);       /* Top 16 bits of time */
 328         PUTLONG(timesigned, cp2);
 329         PUTSHORT(NS_TSIG_FUDGE, cp2);
 330
 331         dst_sign_data(SIG_MODE_UPDATE, state->key, &state->ctx,
 332                       buf, (unsigned)(cp2 - buf), NULL, 0);
 333
 334         n = dst_sign_data(SIG_MODE_FINAL, state->key, &state->ctx, NULL, 0,
 335                           state->sig, sizeof(state->sig));
 336         if (n < 0)
 337                 return ISC_R_BADKEY;
 338         state->siglen = n;
 339
 340         /* Add the signature. */
 341         BOUNDS_CHECK(cp, INT16SZ + state->siglen);
 342         PUTSHORT(state->siglen, cp);
 343         memcpy(cp, state->sig, state->siglen);
 344         cp += state->siglen;
 345
 346         /* The original message ID & error. */
 347         BOUNDS_CHECK(cp, INT16SZ + INT16SZ);
 348         PUTSHORT(ntohs(hp->id), cp);    /* already in network order */
 349         PUTSHORT(error, cp);
 350
 351         /* Other data. */
 352         BOUNDS_CHECK(cp, INT16SZ);
 353         PUTSHORT(0, cp);
 354
 355         /* Go back and fill in the length. */
 356         PUTSHORT(cp - lenp - INT16SZ, lenp);
 357
 358         hp->arcount = htons(ntohs(hp->arcount) + 1);
 359         *msglen = (cp - msg);
 360         return ISC_R_SUCCESS;
 361 }
 362 #endif