key.c

   1 /* $OpenBSD: key.c,v 1.69 2007/07/12 05:48:05 ray Exp $ */
   2 /*
   3  * read_bignum():
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *
   6  * As far as I am concerned, the code I have written for this software
   7  * can be used freely for any purpose.  Any derived versions of this
   8  * software must be clearly marked as such, and if the derived work is
   9  * incompatible with the protocol description in the RFC file, it must be
  10  * called by a name other than "ssh" or "Secure Shell".
  11  *
  12  *
  13  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  14  *
  15  * Redistribution and use in source and binary forms, with or without
  16  * modification, are permitted provided that the following conditions
  17  * are met:
  18  * 1. Redistributions of source code must retain the above copyright
  19  *    notice, this list of conditions and the following disclaimer.
  20  * 2. Redistributions in binary form must reproduce the above copyright
  21  *    notice, this list of conditions and the following disclaimer in the
  22  *    documentation and/or other materials provided with the distribution.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  27  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  33  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 #include "includes.h"
  37
  38 #include <sys/types.h>
  39
  40 #include <openssl/evp.h>
  41 #include <openbsd-compat/openssl-compat.h>
  42
  43 #include <stdarg.h>
  44 #include <stdio.h>
  45 #include <string.h>
  46
  47 #include "xmalloc.h"
  48 #include "key.h"
  49 #include "rsa.h"
  50 #include "uuencode.h"
  51 #include "buffer.h"
  52 #include "log.h"
  53
  54 Key *
  55 key_new(int type)
  56 {
  57         Key *k;
  58         RSA *rsa;
  59         DSA *dsa;
  60         k = xcalloc(1, sizeof(*k));
  61         k->type = type;
  62         k->dsa = NULL;
  63         k->rsa = NULL;
  64         switch (k->type) {
  65         case KEY_RSA1:
  66         case KEY_RSA:
  67                 if ((rsa = RSA_new()) == NULL)
  68                         fatal("key_new: RSA_new failed");
  69                 if ((rsa->n = BN_new()) == NULL)
  70                         fatal("key_new: BN_new failed");
  71                 if ((rsa->e = BN_new()) == NULL)
  72                         fatal("key_new: BN_new failed");
  73                 k->rsa = rsa;
  74                 break;
  75         case KEY_DSA:
  76                 if ((dsa = DSA_new()) == NULL)
  77                         fatal("key_new: DSA_new failed");
  78                 if ((dsa->p = BN_new()) == NULL)
  79                         fatal("key_new: BN_new failed");
  80                 if ((dsa->q = BN_new()) == NULL)
  81                         fatal("key_new: BN_new failed");
  82                 if ((dsa->g = BN_new()) == NULL)
  83                         fatal("key_new: BN_new failed");
  84                 if ((dsa->pub_key = BN_new()) == NULL)
  85                         fatal("key_new: BN_new failed");
  86                 k->dsa = dsa;
  87                 break;
  88         case KEY_UNSPEC:
  89                 break;
  90         default:
  91                 fatal("key_new: bad key type %d", k->type);
  92                 break;
  93         }
  94         return k;
  95 }
  96
  97 Key *
  98 key_new_private(int type)
  99 {
 100         Key *k = key_new(type);
 101         switch (k->type) {
 102         case KEY_RSA1:
 103         case KEY_RSA:
 104                 if ((k->rsa->d = BN_new()) == NULL)
 105                         fatal("key_new_private: BN_new failed");
 106                 if ((k->rsa->iqmp = BN_new()) == NULL)
 107                         fatal("key_new_private: BN_new failed");
 108                 if ((k->rsa->q = BN_new()) == NULL)
 109                         fatal("key_new_private: BN_new failed");
 110                 if ((k->rsa->p = BN_new()) == NULL)
 111                         fatal("key_new_private: BN_new failed");
 112                 if ((k->rsa->dmq1 = BN_new()) == NULL)
 113                         fatal("key_new_private: BN_new failed");
 114                 if ((k->rsa->dmp1 = BN_new()) == NULL)
 115                         fatal("key_new_private: BN_new failed");
 116                 break;
 117         case KEY_DSA:
 118                 if ((k->dsa->priv_key = BN_new()) == NULL)
 119                         fatal("key_new_private: BN_new failed");
 120                 break;
 121         case KEY_UNSPEC:
 122                 break;
 123         default:
 124                 break;
 125         }
 126         return k;
 127 }
 128
 129 void
 130 key_free(Key *k)
 131 {
 132         if (k == NULL)
 133                 fatal("key_free: key is NULL");
 134         switch (k->type) {
 135         case KEY_RSA1:
 136         case KEY_RSA:
 137                 if (k->rsa != NULL)
 138                         RSA_free(k->rsa);
 139                 k->rsa = NULL;
 140                 break;
 141         case KEY_DSA:
 142                 if (k->dsa != NULL)
 143                         DSA_free(k->dsa);
 144                 k->dsa = NULL;
 145                 break;
 146         case KEY_UNSPEC:
 147                 break;
 148         default:
 149                 fatal("key_free: bad key type %d", k->type);
 150                 break;
 151         }
 152         xfree(k);
 153 }
 154
 155 int
 156 key_equal(const Key *a, const Key *b)
 157 {
 158         if (a == NULL || b == NULL || a->type != b->type)
 159                 return 0;
 160         switch (a->type) {
 161         case KEY_RSA1:
 162         case KEY_RSA:
 163                 return a->rsa != NULL && b->rsa != NULL &&
 164                     BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
 165                     BN_cmp(a->rsa->n, b->rsa->n) == 0;
 166         case KEY_DSA:
 167                 return a->dsa != NULL && b->dsa != NULL &&
 168                     BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
 169                     BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
 170                     BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
 171                     BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
 172         default:
 173                 fatal("key_equal: bad key type %d", a->type);
 174         }
 175 }
 176
 177 u_char*
 178 key_fingerprint_raw(const Key *k, enum fp_type dgst_type,
 179     u_int *dgst_raw_length)
 180 {
 181         const EVP_MD *md = NULL;
 182         EVP_MD_CTX ctx;
 183         u_char *blob = NULL;
 184         u_char *retval = NULL;
 185         u_int len = 0;
 186         int nlen, elen;
 187
 188         *dgst_raw_length = 0;
 189
 190         switch (dgst_type) {
 191         case SSH_FP_MD5:
 192                 md = EVP_md5();
 193                 break;
 194         case SSH_FP_SHA1:
 195                 md = EVP_sha1();
 196                 break;
 197         default:
 198                 fatal("key_fingerprint_raw: bad digest type %d",
 199                     dgst_type);
 200         }
 201         switch (k->type) {
 202         case KEY_RSA1:
 203                 nlen = BN_num_bytes(k->rsa->n);
 204                 elen = BN_num_bytes(k->rsa->e);
 205                 len = nlen + elen;
 206                 blob = xmalloc(len);
 207                 BN_bn2bin(k->rsa->n, blob);
 208                 BN_bn2bin(k->rsa->e, blob + nlen);
 209                 break;
 210         case KEY_DSA:
 211         case KEY_RSA:
 212                 key_to_blob(k, &blob, &len);
 213                 break;
 214         case KEY_UNSPEC:
 215                 return retval;
 216         default:
 217                 fatal("key_fingerprint_raw: bad key type %d", k->type);
 218                 break;
 219         }
 220         if (blob != NULL) {
 221                 retval = xmalloc(EVP_MAX_MD_SIZE);
 222                 EVP_DigestInit(&ctx, md);
 223                 EVP_DigestUpdate(&ctx, blob, len);
 224                 EVP_DigestFinal(&ctx, retval, dgst_raw_length);
 225                 memset(blob, 0, len);
 226                 xfree(blob);
 227         } else {
 228                 fatal("key_fingerprint_raw: blob is null");
 229         }
 230         return retval;
 231 }
 232
 233 static char *
 234 key_fingerprint_hex(u_char *dgst_raw, u_int dgst_raw_len)
 235 {
 236         char *retval;
 237         u_int i;
 238
 239         retval = xcalloc(1, dgst_raw_len * 3 + 1);
 240         for (i = 0; i < dgst_raw_len; i++) {
 241                 char hex[4];
 242                 snprintf(hex, sizeof(hex), "%02x:", dgst_raw[i]);
 243                 strlcat(retval, hex, dgst_raw_len * 3 + 1);
 244         }
 245
 246         /* Remove the trailing ':' character */
 247         retval[(dgst_raw_len * 3) - 1] = '\0';
 248         return retval;
 249 }
 250
 251 static char *
 252 key_fingerprint_bubblebabble(u_char *dgst_raw, u_int dgst_raw_len)
 253 {
 254         char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
 255         char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
 256             'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
 257         u_int i, j = 0, rounds, seed = 1;
 258         char *retval;
 259
 260         rounds = (dgst_raw_len / 2) + 1;
 261         retval = xcalloc((rounds * 6), sizeof(char));
 262         retval[j++] = 'x';
 263         for (i = 0; i < rounds; i++) {
 264                 u_int idx0, idx1, idx2, idx3, idx4;
 265                 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
 266                         idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
 267                             seed) % 6;
 268                         idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
 269                         idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
 270                             (seed / 6)) % 6;
 271                         retval[j++] = vowels[idx0];
 272                         retval[j++] = consonants[idx1];
 273                         retval[j++] = vowels[idx2];
 274                         if ((i + 1) < rounds) {
 275                                 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
 276                                 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
 277                                 retval[j++] = consonants[idx3];
 278                                 retval[j++] = '-';
 279                                 retval[j++] = consonants[idx4];
 280                                 seed = ((seed * 5) +
 281                                     ((((u_int)(dgst_raw[2 * i])) * 7) +
 282                                     ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
 283                         }
 284                 } else {
 285                         idx0 = seed % 6;
 286                         idx1 = 16;
 287                         idx2 = seed / 6;
 288                         retval[j++] = vowels[idx0];
 289                         retval[j++] = consonants[idx1];
 290                         retval[j++] = vowels[idx2];
 291                 }
 292         }
 293         retval[j++] = 'x';
 294         retval[j++] = '\0';
 295         return retval;
 296 }
 297
 298 char *
 299 key_fingerprint(const Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep)
 300 {
 301         char *retval = NULL;
 302         u_char *dgst_raw;
 303         u_int dgst_raw_len;
 304
 305         dgst_raw = key_fingerprint_raw(k, dgst_type, &dgst_raw_len);
 306         if (!dgst_raw)
 307                 fatal("key_fingerprint: null from key_fingerprint_raw()");
 308         switch (dgst_rep) {
 309         case SSH_FP_HEX:
 310                 retval = key_fingerprint_hex(dgst_raw, dgst_raw_len);
 311                 break;
 312         case SSH_FP_BUBBLEBABBLE:
 313                 retval = key_fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
 314                 break;
 315         default:
 316                 fatal("key_fingerprint_ex: bad digest representation %d",
 317                     dgst_rep);
 318                 break;
 319         }
 320         memset(dgst_raw, 0, dgst_raw_len);
 321         xfree(dgst_raw);
 322         return retval;
 323 }
 324
 325 /*
 326  * Reads a multiple-precision integer in decimal from the buffer, and advances
 327  * the pointer.  The integer must already be initialized.  This function is
 328  * permitted to modify the buffer.  This leaves *cpp to point just beyond the
 329  * last processed (and maybe modified) character.  Note that this may modify
 330  * the buffer containing the number.
 331  */
 332 static int
 333 read_bignum(char **cpp, BIGNUM * value)
 334 {
 335         char *cp = *cpp;
 336         int old;
 337
 338         /* Skip any leading whitespace. */
 339         for (; *cp == ' ' || *cp == '\t'; cp++)
 340                 ;
 341
 342         /* Check that it begins with a decimal digit. */
 343         if (*cp < '0' || *cp > '9')
 344                 return 0;
 345
 346         /* Save starting position. */
 347         *cpp = cp;
 348
 349         /* Move forward until all decimal digits skipped. */
 350         for (; *cp >= '0' && *cp <= '9'; cp++)
 351                 ;
 352
 353         /* Save the old terminating character, and replace it by \0. */
 354         old = *cp;
 355         *cp = 0;
 356
 357         /* Parse the number. */
 358         if (BN_dec2bn(&value, *cpp) == 0)
 359                 return 0;
 360
 361         /* Restore old terminating character. */
 362         *cp = old;
 363
 364         /* Move beyond the number and return success. */
 365         *cpp = cp;
 366         return 1;
 367 }
 368
 369 static int
 370 write_bignum(FILE *f, BIGNUM *num)
 371 {
 372         char *buf = BN_bn2dec(num);
 373         if (buf == NULL) {
 374                 error("write_bignum: BN_bn2dec() failed");
 375                 return 0;
 376         }
 377         fprintf(f, " %s", buf);
 378         OPENSSL_free(buf);
 379         return 1;
 380 }
 381
 382 /* returns 1 ok, -1 error */
 383 int
 384 key_read(Key *ret, char **cpp)
 385 {
 386         Key *k;
 387         int success = -1;
 388         char *cp, *space;
 389         int len, n, type;
 390         u_int bits;
 391         u_char *blob;
 392
 393         cp = *cpp;
 394
 395         switch (ret->type) {
 396         case KEY_RSA1:
 397                 /* Get number of bits. */
 398                 if (*cp < '0' || *cp > '9')
 399                         return -1;      /* Bad bit count... */
 400                 for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
 401                         bits = 10 * bits + *cp - '0';
 402                 if (bits == 0)
 403                         return -1;
 404                 *cpp = cp;
 405                 /* Get public exponent, public modulus. */
 406                 if (!read_bignum(cpp, ret->rsa->e))
 407                         return -1;
 408                 if (!read_bignum(cpp, ret->rsa->n))
 409                         return -1;
 410                 success = 1;
 411                 break;
 412         case KEY_UNSPEC:
 413         case KEY_RSA:
 414         case KEY_DSA:
 415                 space = strchr(cp, ' ');
 416                 if (space == NULL) {
 417                         debug3("key_read: missing whitespace");
 418                         return -1;
 419                 }
 420                 *space = '\0';
 421                 type = key_type_from_name(cp);
 422                 *space = ' ';
 423                 if (type == KEY_UNSPEC) {
 424                         debug3("key_read: missing keytype");
 425                         return -1;
 426                 }
 427                 cp = space+1;
 428                 if (*cp == '\0') {
 429                         debug3("key_read: short string");
 430                         return -1;
 431                 }
 432                 if (ret->type == KEY_UNSPEC) {
 433                         ret->type = type;
 434                 } else if (ret->type != type) {
 435                         /* is a key, but different type */
 436                         debug3("key_read: type mismatch");
 437                         return -1;
 438                 }
 439                 len = 2*strlen(cp);
 440                 blob = xmalloc(len);
 441                 n = uudecode(cp, blob, len);
 442                 if (n < 0) {
 443                         error("key_read: uudecode %s failed", cp);
 444                         xfree(blob);
 445                         return -1;
 446                 }
 447                 k = key_from_blob(blob, (u_int)n);
 448                 xfree(blob);
 449                 if (k == NULL) {
 450                         error("key_read: key_from_blob %s failed", cp);
 451                         return -1;
 452                 }
 453                 if (k->type != type) {
 454                         error("key_read: type mismatch: encoding error");
 455                         key_free(k);
 456                         return -1;
 457                 }
 458 /*XXXX*/
 459                 if (ret->type == KEY_RSA) {
 460                         if (ret->rsa != NULL)
 461                                 RSA_free(ret->rsa);
 462                         ret->rsa = k->rsa;
 463                         k->rsa = NULL;
 464                         success = 1;
 465 #ifdef DEBUG_PK
 466                         RSA_print_fp(stderr, ret->rsa, 8);
 467 #endif
 468                 } else {
 469                         if (ret->dsa != NULL)
 470                                 DSA_free(ret->dsa);
 471                         ret->dsa = k->dsa;
 472                         k->dsa = NULL;
 473                         success = 1;
 474 #ifdef DEBUG_PK
 475                         DSA_print_fp(stderr, ret->dsa, 8);
 476 #endif
 477                 }
 478 /*XXXX*/
 479                 key_free(k);
 480                 if (success != 1)
 481                         break;
 482                 /* advance cp: skip whitespace and data */
 483                 while (*cp == ' ' || *cp == '\t')
 484                         cp++;
 485                 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 486                         cp++;
 487                 *cpp = cp;
 488                 break;
 489         default:
 490                 fatal("key_read: bad key type: %d", ret->type);
 491                 break;
 492         }
 493         return success;
 494 }
 495
 496 int
 497 key_write(const Key *key, FILE *f)
 498 {
 499         int n, success = 0;
 500         u_int len, bits = 0;
 501         u_char *blob;
 502         char *uu;
 503
 504         if (key->type == KEY_RSA1 && key->rsa != NULL) {
 505                 /* size of modulus 'n' */
 506                 bits = BN_num_bits(key->rsa->n);
 507                 fprintf(f, "%u", bits);
 508                 if (write_bignum(f, key->rsa->e) &&
 509                     write_bignum(f, key->rsa->n)) {
 510                         success = 1;
 511                 } else {
 512                         error("key_write: failed for RSA key");
 513                 }
 514         } else if ((key->type == KEY_DSA && key->dsa != NULL) ||
 515             (key->type == KEY_RSA && key->rsa != NULL)) {
 516                 key_to_blob(key, &blob, &len);
 517                 uu = xmalloc(2*len);
 518                 n = uuencode(blob, len, uu, 2*len);
 519                 if (n > 0) {
 520                         fprintf(f, "%s %s", key_ssh_name(key), uu);
 521                         success = 1;
 522                 }
 523                 xfree(blob);
 524                 xfree(uu);
 525         }
 526         return success;
 527 }
 528
 529 const char *
 530 key_type(const Key *k)
 531 {
 532         switch (k->type) {
 533         case KEY_RSA1:
 534                 return "RSA1";
 535         case KEY_RSA:
 536                 return "RSA";
 537         case KEY_DSA:
 538                 return "DSA";
 539         }
 540         return "unknown";
 541 }
 542
 543 const char *
 544 key_ssh_name(const Key *k)
 545 {
 546         switch (k->type) {
 547         case KEY_RSA:
 548                 return "ssh-rsa";
 549         case KEY_DSA:
 550                 return "ssh-dss";
 551         }
 552         return "ssh-unknown";
 553 }
 554
 555 u_int
 556 key_size(const Key *k)
 557 {
 558         switch (k->type) {
 559         case KEY_RSA1:
 560         case KEY_RSA:
 561                 return BN_num_bits(k->rsa->n);
 562         case KEY_DSA:
 563                 return BN_num_bits(k->dsa->p);
 564         }
 565         return 0;
 566 }
 567
 568 static RSA *
 569 rsa_generate_private_key(u_int bits)
 570 {
 571         RSA *private;
 572
 573         private = RSA_generate_key(bits, 35, NULL, NULL);
 574         if (private == NULL)
 575                 fatal("rsa_generate_private_key: key generation failed.");
 576         return private;
 577 }
 578
 579 static DSA*
 580 dsa_generate_private_key(u_int bits)
 581 {
 582         DSA *private = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
 583
 584         if (private == NULL)
 585                 fatal("dsa_generate_private_key: DSA_generate_parameters failed");
 586         if (!DSA_generate_key(private))
 587                 fatal("dsa_generate_private_key: DSA_generate_key failed.");
 588         if (private == NULL)
 589                 fatal("dsa_generate_private_key: NULL.");
 590         return private;
 591 }
 592
 593 Key *
 594 key_generate(int type, u_int bits)
 595 {
 596         Key *k = key_new(KEY_UNSPEC);
 597         switch (type) {
 598         case KEY_DSA:
 599                 k->dsa = dsa_generate_private_key(bits);
 600                 break;
 601         case KEY_RSA:
 602         case KEY_RSA1:
 603                 k->rsa = rsa_generate_private_key(bits);
 604                 break;
 605         default:
 606                 fatal("key_generate: unknown type %d", type);
 607         }
 608         k->type = type;
 609         return k;
 610 }
 611
 612 Key *
 613 key_from_private(const Key *k)
 614 {
 615         Key *n = NULL;
 616         switch (k->type) {
 617         case KEY_DSA:
 618                 n = key_new(k->type);
 619                 if ((BN_copy(n->dsa->p, k->dsa->p) == NULL) ||
 620                     (BN_copy(n->dsa->q, k->dsa->q) == NULL) ||
 621                     (BN_copy(n->dsa->g, k->dsa->g) == NULL) ||
 622                     (BN_copy(n->dsa->pub_key, k->dsa->pub_key) == NULL))
 623                         fatal("key_from_private: BN_copy failed");
 624                 break;
 625         case KEY_RSA:
 626         case KEY_RSA1:
 627                 n = key_new(k->type);
 628                 if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) ||
 629                     (BN_copy(n->rsa->e, k->rsa->e) == NULL))
 630                         fatal("key_from_private: BN_copy failed");
 631                 break;
 632         default:
 633                 fatal("key_from_private: unknown type %d", k->type);
 634                 break;
 635         }
 636         return n;
 637 }
 638
 639 int
 640 key_type_from_name(char *name)
 641 {
 642         if (strcmp(name, "rsa1") == 0) {
 643                 return KEY_RSA1;
 644         } else if (strcmp(name, "rsa") == 0) {
 645                 return KEY_RSA;
 646         } else if (strcmp(name, "dsa") == 0) {
 647                 return KEY_DSA;
 648         } else if (strcmp(name, "ssh-rsa") == 0) {
 649                 return KEY_RSA;
 650         } else if (strcmp(name, "ssh-dss") == 0) {
 651                 return KEY_DSA;
 652         }
 653         debug2("key_type_from_name: unknown key type '%s'", name);
 654         return KEY_UNSPEC;
 655 }
 656
 657 int
 658 key_names_valid2(const char *names)
 659 {
 660         char *s, *cp, *p;
 661
 662         if (names == NULL || strcmp(names, "") == 0)
 663                 return 0;
 664         s = cp = xstrdup(names);
 665         for ((p = strsep(&cp, ",")); p && *p != '\0';
 666             (p = strsep(&cp, ","))) {
 667                 switch (key_type_from_name(p)) {
 668                 case KEY_RSA1:
 669                 case KEY_UNSPEC:
 670                         xfree(s);
 671                         return 0;
 672                 }
 673         }
 674         debug3("key names ok: [%s]", names);
 675         xfree(s);
 676         return 1;
 677 }
 678
 679 Key *
 680 key_from_blob(const u_char *blob, u_int blen)
 681 {
 682         Buffer b;
 683         int rlen, type;
 684         char *ktype = NULL;
 685         Key *key = NULL;
 686
 687 #ifdef DEBUG_PK
 688         dump_base64(stderr, blob, blen);
 689 #endif
 690         buffer_init(&b);
 691         buffer_append(&b, blob, blen);
 692         if ((ktype = buffer_get_string_ret(&b, NULL)) == NULL) {
 693                 error("key_from_blob: can't read key type");
 694                 goto out;
 695         }
 696
 697         type = key_type_from_name(ktype);
 698
 699         switch (type) {
 700         case KEY_RSA:
 701                 key = key_new(type);
 702                 if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 ||
 703                     buffer_get_bignum2_ret(&b, key->rsa->n) == -1) {
 704                         error("key_from_blob: can't read rsa key");
 705                         key_free(key);
 706                         key = NULL;
 707                         goto out;
 708                 }
 709 #ifdef DEBUG_PK
 710                 RSA_print_fp(stderr, key->rsa, 8);
 711 #endif
 712                 break;
 713         case KEY_DSA:
 714                 key = key_new(type);
 715                 if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 ||
 716                     buffer_get_bignum2_ret(&b, key->dsa->q) == -1 ||
 717                     buffer_get_bignum2_ret(&b, key->dsa->g) == -1 ||
 718                     buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) {
 719                         error("key_from_blob: can't read dsa key");
 720                         key_free(key);
 721                         key = NULL;
 722                         goto out;
 723                 }
 724 #ifdef DEBUG_PK
 725                 DSA_print_fp(stderr, key->dsa, 8);
 726 #endif
 727                 break;
 728         case KEY_UNSPEC:
 729                 key = key_new(type);
 730                 break;
 731         default:
 732                 error("key_from_blob: cannot handle type %s", ktype);
 733                 goto out;
 734         }
 735         rlen = buffer_len(&b);
 736         if (key != NULL && rlen != 0)
 737                 error("key_from_blob: remaining bytes in key blob %d", rlen);
 738  out:
 739         if (ktype != NULL)
 740                 xfree(ktype);
 741         buffer_free(&b);
 742         return key;
 743 }
 744
 745 int
 746 key_to_blob(const Key *key, u_char **blobp, u_int *lenp)
 747 {
 748         Buffer b;
 749         int len;
 750
 751         if (key == NULL) {
 752                 error("key_to_blob: key == NULL");
 753                 return 0;
 754         }
 755         buffer_init(&b);
 756         switch (key->type) {
 757         case KEY_DSA:
 758                 buffer_put_cstring(&b, key_ssh_name(key));
 759                 buffer_put_bignum2(&b, key->dsa->p);
 760                 buffer_put_bignum2(&b, key->dsa->q);
 761                 buffer_put_bignum2(&b, key->dsa->g);
 762                 buffer_put_bignum2(&b, key->dsa->pub_key);
 763                 break;
 764         case KEY_RSA:
 765                 buffer_put_cstring(&b, key_ssh_name(key));
 766                 buffer_put_bignum2(&b, key->rsa->e);
 767                 buffer_put_bignum2(&b, key->rsa->n);
 768                 break;
 769         default:
 770                 error("key_to_blob: unsupported key type %d", key->type);
 771                 buffer_free(&b);
 772                 return 0;
 773         }
 774         len = buffer_len(&b);
 775         if (lenp != NULL)
 776                 *lenp = len;
 777         if (blobp != NULL) {
 778                 *blobp = xmalloc(len);
 779                 memcpy(*blobp, buffer_ptr(&b), len);
 780         }
 781         memset(buffer_ptr(&b), 0, len);
 782         buffer_free(&b);
 783         return len;
 784 }
 785
 786 int
 787 key_sign(
 788     const Key *key,
 789     u_char **sigp, u_int *lenp,
 790     const u_char *data, u_int datalen)
 791 {
 792         switch (key->type) {
 793         case KEY_DSA:
 794                 return ssh_dss_sign(key, sigp, lenp, data, datalen);
 795         case KEY_RSA:
 796                 return ssh_rsa_sign(key, sigp, lenp, data, datalen);
 797         default:
 798                 error("key_sign: invalid key type %d", key->type);
 799                 return -1;
 800         }
 801 }
 802
 803 /*
 804  * key_verify returns 1 for a correct signature, 0 for an incorrect signature
 805  * and -1 on error.
 806  */
 807 int
 808 key_verify(
 809     const Key *key,
 810     const u_char *signature, u_int signaturelen,
 811     const u_char *data, u_int datalen)
 812 {
 813         if (signaturelen == 0)
 814                 return -1;
 815
 816         switch (key->type) {
 817         case KEY_DSA:
 818                 return ssh_dss_verify(key, signature, signaturelen, data, datalen);
 819         case KEY_RSA:
 820                 return ssh_rsa_verify(key, signature, signaturelen, data, datalen);
 821         default:
 822                 error("key_verify: invalid key type %d", key->type);
 823                 return -1;
 824         }
 825 }
 826
 827 /* Converts a private to a public key */
 828 Key *
 829 key_demote(const Key *k)
 830 {
 831         Key *pk;
 832
 833         pk = xcalloc(1, sizeof(*pk));
 834         pk->type = k->type;
 835         pk->flags = k->flags;
 836         pk->dsa = NULL;
 837         pk->rsa = NULL;
 838
 839         switch (k->type) {
 840         case KEY_RSA1:
 841         case KEY_RSA:
 842                 if ((pk->rsa = RSA_new()) == NULL)
 843                         fatal("key_demote: RSA_new failed");
 844                 if ((pk->rsa->e = BN_dup(k->rsa->e)) == NULL)
 845                         fatal("key_demote: BN_dup failed");
 846                 if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL)
 847                         fatal("key_demote: BN_dup failed");
 848                 break;
 849         case KEY_DSA:
 850                 if ((pk->dsa = DSA_new()) == NULL)
 851                         fatal("key_demote: DSA_new failed");
 852                 if ((pk->dsa->p = BN_dup(k->dsa->p)) == NULL)
 853                         fatal("key_demote: BN_dup failed");
 854                 if ((pk->dsa->q = BN_dup(k->dsa->q)) == NULL)
 855                         fatal("key_demote: BN_dup failed");
 856                 if ((pk->dsa->g = BN_dup(k->dsa->g)) == NULL)
 857                         fatal("key_demote: BN_dup failed");
 858                 if ((pk->dsa->pub_key = BN_dup(k->dsa->pub_key)) == NULL)
 859                         fatal("key_demote: BN_dup failed");
 860                 break;
 861         default:
 862                 fatal("key_free: bad key type %d", k->type);
 863                 break;
 864         }
 865
 866         return (pk);
 867 }