crypto/openssh-4/key.c

   1 /* $OpenBSD: key.c,v 1.68 2006/11/06 21:25:28 markus 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
  42 #include <stdarg.h>
  43 #include <stdio.h>
  44 #include <string.h>
  45
  46 #include "xmalloc.h"
  47 #include "key.h"
  48 #include "rsa.h"
  49 #include "uuencode.h"
  50 #include "buffer.h"
  51 #include "log.h"
  52
  53 Key *
  54 key_new(int type)
  55 {
  56         Key *k;
  57         RSA *rsa;
  58         DSA *dsa;
  59         k = xcalloc(1, sizeof(*k));
  60         k->type = type;
  61         k->dsa = NULL;
  62         k->rsa = NULL;
  63         switch (k->type) {
  64         case KEY_RSA1:
  65         case KEY_RSA:
  66                 if ((rsa = RSA_new()) == NULL)
  67                         fatal("key_new: RSA_new failed");
  68                 if ((rsa->n = BN_new()) == NULL)
  69                         fatal("key_new: BN_new failed");
  70                 if ((rsa->e = BN_new()) == NULL)
  71                         fatal("key_new: BN_new failed");
  72                 k->rsa = rsa;
  73                 break;
  74         case KEY_DSA:
  75                 if ((dsa = DSA_new()) == NULL)
  76                         fatal("key_new: DSA_new failed");
  77                 if ((dsa->p = BN_new()) == NULL)
  78                         fatal("key_new: BN_new failed");
  79                 if ((dsa->q = BN_new()) == NULL)
  80                         fatal("key_new: BN_new failed");
  81                 if ((dsa->g = BN_new()) == NULL)
  82                         fatal("key_new: BN_new failed");
  83                 if ((dsa->pub_key = BN_new()) == NULL)
  84                         fatal("key_new: BN_new failed");
  85                 k->dsa = dsa;
  86                 break;
  87         case KEY_UNSPEC:
  88                 break;
  89         default:
  90                 fatal("key_new: bad key type %d", k->type);
  91                 break;
  92         }
  93         return k;
  94 }
  95
  96 Key *
  97 key_new_private(int type)
  98 {
  99         Key *k = key_new(type);
 100         switch (k->type) {
 101         case KEY_RSA1:
 102         case KEY_RSA:
 103                 if ((k->rsa->d = BN_new()) == NULL)
 104                         fatal("key_new_private: BN_new failed");
 105                 if ((k->rsa->iqmp = BN_new()) == NULL)
 106                         fatal("key_new_private: BN_new failed");
 107                 if ((k->rsa->q = BN_new()) == NULL)
 108                         fatal("key_new_private: BN_new failed");
 109                 if ((k->rsa->p = BN_new()) == NULL)
 110                         fatal("key_new_private: BN_new failed");
 111                 if ((k->rsa->dmq1 = BN_new()) == NULL)
 112                         fatal("key_new_private: BN_new failed");
 113                 if ((k->rsa->dmp1 = BN_new()) == NULL)
 114                         fatal("key_new_private: BN_new failed");
 115                 break;
 116         case KEY_DSA:
 117                 if ((k->dsa->priv_key = BN_new()) == NULL)
 118                         fatal("key_new_private: BN_new failed");
 119                 break;
 120         case KEY_UNSPEC:
 121                 break;
 122         default:
 123                 break;
 124         }
 125         return k;
 126 }
 127
 128 void
 129 key_free(Key *k)
 130 {
 131         if (k == NULL)
 132                 fatal("key_free: key is NULL");
 133         switch (k->type) {
 134         case KEY_RSA1:
 135         case KEY_RSA:
 136                 if (k->rsa != NULL)
 137                         RSA_free(k->rsa);
 138                 k->rsa = NULL;
 139                 break;
 140         case KEY_DSA:
 141                 if (k->dsa != NULL)
 142                         DSA_free(k->dsa);
 143                 k->dsa = NULL;
 144                 break;
 145         case KEY_UNSPEC:
 146                 break;
 147         default:
 148                 fatal("key_free: bad key type %d", k->type);
 149                 break;
 150         }
 151         xfree(k);
 152 }
 153
 154 int
 155 key_equal(const Key *a, const Key *b)
 156 {
 157         if (a == NULL || b == NULL || a->type != b->type)
 158                 return 0;
 159         switch (a->type) {
 160         case KEY_RSA1:
 161         case KEY_RSA:
 162                 return a->rsa != NULL && b->rsa != NULL &&
 163                     BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
 164                     BN_cmp(a->rsa->n, b->rsa->n) == 0;
 165         case KEY_DSA:
 166                 return a->dsa != NULL && b->dsa != NULL &&
 167                     BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
 168                     BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
 169                     BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
 170                     BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
 171         default:
 172                 fatal("key_equal: bad key type %d", a->type);
 173                 break;
 174         }
 175         return 0;
 176 }
 177
 178 u_char*
 179 key_fingerprint_raw(const Key *k, enum fp_type dgst_type,
 180     u_int *dgst_raw_length)
 181 {
 182         const EVP_MD *md = NULL;
 183         EVP_MD_CTX ctx;
 184         u_char *blob = NULL;
 185         u_char *retval = NULL;
 186         u_int len = 0;
 187         int nlen, elen;
 188
 189         *dgst_raw_length = 0;
 190
 191         switch (dgst_type) {
 192         case SSH_FP_MD5:
 193                 md = EVP_md5();
 194                 break;
 195         case SSH_FP_SHA1:
 196                 md = EVP_sha1();
 197                 break;
 198         default:
 199                 fatal("key_fingerprint_raw: bad digest type %d",
 200                     dgst_type);
 201         }
 202         switch (k->type) {
 203         case KEY_RSA1:
 204                 nlen = BN_num_bytes(k->rsa->n);
 205                 elen = BN_num_bytes(k->rsa->e);
 206                 len = nlen + elen;
 207                 blob = xmalloc(len);
 208                 BN_bn2bin(k->rsa->n, blob);
 209                 BN_bn2bin(k->rsa->e, blob + nlen);
 210                 break;
 211         case KEY_DSA:
 212         case KEY_RSA:
 213                 key_to_blob(k, &blob, &len);
 214                 break;
 215         case KEY_UNSPEC:
 216                 return retval;
 217         default:
 218                 fatal("key_fingerprint_raw: bad key type %d", k->type);
 219                 break;
 220         }
 221         if (blob != NULL) {
 222                 retval = xmalloc(EVP_MAX_MD_SIZE);
 223                 EVP_DigestInit(&ctx, md);
 224                 EVP_DigestUpdate(&ctx, blob, len);
 225                 EVP_DigestFinal(&ctx, retval, dgst_raw_length);
 226                 memset(blob, 0, len);
 227                 xfree(blob);
 228         } else {
 229                 fatal("key_fingerprint_raw: blob is null");
 230         }
 231         return retval;
 232 }
 233
 234 static char *
 235 key_fingerprint_hex(u_char *dgst_raw, u_int dgst_raw_len)
 236 {
 237         char *retval;
 238         u_int i;
 239
 240         retval = xcalloc(1, dgst_raw_len * 3 + 1);
 241         for (i = 0; i < dgst_raw_len; i++) {
 242                 char hex[4];
 243                 snprintf(hex, sizeof(hex), "%02x:", dgst_raw[i]);
 244                 strlcat(retval, hex, dgst_raw_len * 3 + 1);
 245         }
 246
 247         /* Remove the trailing ':' character */
 248         retval[(dgst_raw_len * 3) - 1] = '\0';
 249         return retval;
 250 }
 251
 252 static char *
 253 key_fingerprint_bubblebabble(u_char *dgst_raw, u_int dgst_raw_len)
 254 {
 255         char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
 256         char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
 257             'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
 258         u_int i, j = 0, rounds, seed = 1;
 259         char *retval;
 260
 261         rounds = (dgst_raw_len / 2) + 1;
 262         retval = xcalloc((rounds * 6), sizeof(char));
 263         retval[j++] = 'x';
 264         for (i = 0; i < rounds; i++) {
 265                 u_int idx0, idx1, idx2, idx3, idx4;
 266                 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
 267                         idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
 268                             seed) % 6;
 269                         idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
 270                         idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
 271                             (seed / 6)) % 6;
 272                         retval[j++] = vowels[idx0];
 273                         retval[j++] = consonants[idx1];
 274                         retval[j++] = vowels[idx2];
 275                         if ((i + 1) < rounds) {
 276                                 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
 277                                 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
 278                                 retval[j++] = consonants[idx3];
 279                                 retval[j++] = '-';
 280                                 retval[j++] = consonants[idx4];
 281                                 seed = ((seed * 5) +
 282                                     ((((u_int)(dgst_raw[2 * i])) * 7) +
 283                                     ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
 284                         }
 285                 } else {
 286                         idx0 = seed % 6;
 287                         idx1 = 16;
 288                         idx2 = seed / 6;
 289                         retval[j++] = vowels[idx0];
 290                         retval[j++] = consonants[idx1];
 291                         retval[j++] = vowels[idx2];
 292                 }
 293         }
 294         retval[j++] = 'x';
 295         retval[j++] = '\0';
 296         return retval;
 297 }
 298
 299 char *
 300 key_fingerprint(const Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep)
 301 {
 302         char *retval = NULL;
 303         u_char *dgst_raw;
 304         u_int dgst_raw_len;
 305
 306         dgst_raw = key_fingerprint_raw(k, dgst_type, &dgst_raw_len);
 307         if (!dgst_raw)
 308                 fatal("key_fingerprint: null from key_fingerprint_raw()");
 309         switch (dgst_rep) {
 310         case SSH_FP_HEX:
 311                 retval = key_fingerprint_hex(dgst_raw, dgst_raw_len);
 312                 break;
 313         case SSH_FP_BUBBLEBABBLE:
 314                 retval = key_fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
 315                 break;
 316         default:
 317                 fatal("key_fingerprint_ex: bad digest representation %d",
 318                     dgst_rep);
 319                 break;
 320         }
 321         memset(dgst_raw, 0, dgst_raw_len);
 322         xfree(dgst_raw);
 323         return retval;
 324 }
 325
 326 /*
 327  * Reads a multiple-precision integer in decimal from the buffer, and advances
 328  * the pointer.  The integer must already be initialized.  This function is
 329  * permitted to modify the buffer.  This leaves *cpp to point just beyond the
 330  * last processed (and maybe modified) character.  Note that this may modify
 331  * the buffer containing the number.
 332  */
 333 static int
 334 read_bignum(char **cpp, BIGNUM * value)
 335 {
 336         char *cp = *cpp;
 337         int old;
 338
 339         /* Skip any leading whitespace. */
 340         for (; *cp == ' ' || *cp == '\t'; cp++)
 341                 ;
 342
 343         /* Check that it begins with a decimal digit. */
 344         if (*cp < '0' || *cp > '9')
 345                 return 0;
 346
 347         /* Save starting position. */
 348         *cpp = cp;
 349
 350         /* Move forward until all decimal digits skipped. */
 351         for (; *cp >= '0' && *cp <= '9'; cp++)
 352                 ;
 353
 354         /* Save the old terminating character, and replace it by \0. */
 355         old = *cp;
 356         *cp = 0;
 357
 358         /* Parse the number. */
 359         if (BN_dec2bn(&value, *cpp) == 0)
 360                 return 0;
 361
 362         /* Restore old terminating character. */
 363         *cp = old;
 364
 365         /* Move beyond the number and return success. */
 366         *cpp = cp;
 367         return 1;
 368 }
 369
 370 static int
 371 write_bignum(FILE *f, BIGNUM *num)
 372 {
 373         char *buf = BN_bn2dec(num);
 374         if (buf == NULL) {
 375                 error("write_bignum: BN_bn2dec() failed");
 376                 return 0;
 377         }
 378         fprintf(f, " %s", buf);
 379         OPENSSL_free(buf);
 380         return 1;
 381 }
 382
 383 /* returns 1 ok, -1 error */
 384 int
 385 key_read(Key *ret, char **cpp)
 386 {
 387         Key *k;
 388         int success = -1;
 389         char *cp, *space;
 390         int len, n, type;
 391         u_int bits;
 392         u_char *blob;
 393
 394         cp = *cpp;
 395
 396         switch (ret->type) {
 397         case KEY_RSA1:
 398                 /* Get number of bits. */
 399                 if (*cp < '0' || *cp > '9')
 400                         return -1;      /* Bad bit count... */
 401                 for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
 402                         bits = 10 * bits + *cp - '0';
 403                 if (bits == 0)
 404                         return -1;
 405                 *cpp = cp;
 406                 /* Get public exponent, public modulus. */
 407                 if (!read_bignum(cpp, ret->rsa->e))
 408                         return -1;
 409                 if (!read_bignum(cpp, ret->rsa->n))
 410                         return -1;
 411                 success = 1;
 412                 break;
 413         case KEY_UNSPEC:
 414         case KEY_RSA:
 415         case KEY_DSA:
 416                 space = strchr(cp, ' ');
 417                 if (space == NULL) {
 418                         debug3("key_read: missing whitespace");
 419                         return -1;
 420                 }
 421                 *space = '\0';
 422                 type = key_type_from_name(cp);
 423                 *space = ' ';
 424                 if (type == KEY_UNSPEC) {
 425                         debug3("key_read: missing keytype");
 426                         return -1;
 427                 }
 428                 cp = space+1;
 429                 if (*cp == '\0') {
 430                         debug3("key_read: short string");
 431                         return -1;
 432                 }
 433                 if (ret->type == KEY_UNSPEC) {
 434                         ret->type = type;
 435                 } else if (ret->type != type) {
 436                         /* is a key, but different type */
 437                         debug3("key_read: type mismatch");
 438                         return -1;
 439                 }
 440                 len = 2*strlen(cp);
 441                 blob = xmalloc(len);
 442                 n = uudecode(cp, blob, len);
 443                 if (n < 0) {
 444                         error("key_read: uudecode %s failed", cp);
 445                         xfree(blob);
 446                         return -1;
 447                 }
 448                 k = key_from_blob(blob, (u_int)n);
 449                 xfree(blob);
 450                 if (k == NULL) {
 451                         error("key_read: key_from_blob %s failed", cp);
 452                         return -1;
 453                 }
 454                 if (k->type != type) {
 455                         error("key_read: type mismatch: encoding error");
 456                         key_free(k);
 457                         return -1;
 458                 }
 459 /*XXXX*/
 460                 if (ret->type == KEY_RSA) {
 461                         if (ret->rsa != NULL)
 462                                 RSA_free(ret->rsa);
 463                         ret->rsa = k->rsa;
 464                         k->rsa = NULL;
 465                         success = 1;
 466 #ifdef DEBUG_PK
 467                         RSA_print_fp(stderr, ret->rsa, 8);
 468 #endif
 469                 } else {
 470                         if (ret->dsa != NULL)
 471                                 DSA_free(ret->dsa);
 472                         ret->dsa = k->dsa;
 473                         k->dsa = NULL;
 474                         success = 1;
 475 #ifdef DEBUG_PK
 476                         DSA_print_fp(stderr, ret->dsa, 8);
 477 #endif
 478                 }
 479 /*XXXX*/
 480                 key_free(k);
 481                 if (success != 1)
 482                         break;
 483                 /* advance cp: skip whitespace and data */
 484                 while (*cp == ' ' || *cp == '\t')
 485                         cp++;
 486                 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 487                         cp++;
 488                 *cpp = cp;
 489                 break;
 490         default:
 491                 fatal("key_read: bad key type: %d", ret->type);
 492                 break;
 493         }
 494         return success;
 495 }
 496
 497 int
 498 key_write(const Key *key, FILE *f)
 499 {
 500         int n, success = 0;
 501         u_int len, bits = 0;
 502         u_char *blob;
 503         char *uu;
 504
 505         if (key->type == KEY_RSA1 && key->rsa != NULL) {
 506                 /* size of modulus 'n' */
 507                 bits = BN_num_bits(key->rsa->n);
 508                 fprintf(f, "%u", bits);
 509                 if (write_bignum(f, key->rsa->e) &&
 510                     write_bignum(f, key->rsa->n)) {
 511                         success = 1;
 512                 } else {
 513                         error("key_write: failed for RSA key");
 514                 }
 515         } else if ((key->type == KEY_DSA && key->dsa != NULL) ||
 516             (key->type == KEY_RSA && key->rsa != NULL)) {
 517                 key_to_blob(key, &blob, &len);
 518                 uu = xmalloc(2*len);
 519                 n = uuencode(blob, len, uu, 2*len);
 520                 if (n > 0) {
 521                         fprintf(f, "%s %s", key_ssh_name(key), uu);
 522                         success = 1;
 523                 }
 524                 xfree(blob);
 525                 xfree(uu);
 526         }
 527         return success;
 528 }
 529
 530 const char *
 531 key_type(const Key *k)
 532 {
 533         switch (k->type) {
 534         case KEY_RSA1:
 535                 return "RSA1";
 536         case KEY_RSA:
 537                 return "RSA";
 538         case KEY_DSA:
 539                 return "DSA";
 540         }
 541         return "unknown";
 542 }
 543
 544 const char *
 545 key_ssh_name(const Key *k)
 546 {
 547         switch (k->type) {
 548         case KEY_RSA:
 549                 return "ssh-rsa";
 550         case KEY_DSA:
 551                 return "ssh-dss";
 552         }
 553         return "ssh-unknown";
 554 }
 555
 556 u_int
 557 key_size(const Key *k)
 558 {
 559         switch (k->type) {
 560         case KEY_RSA1:
 561         case KEY_RSA:
 562                 return BN_num_bits(k->rsa->n);
 563         case KEY_DSA:
 564                 return BN_num_bits(k->dsa->p);
 565         }
 566         return 0;
 567 }
 568
 569 static RSA *
 570 rsa_generate_private_key(u_int bits)
 571 {
 572         RSA *private;
 573
 574         private = RSA_generate_key(bits, 35, NULL, NULL);
 575         if (private == NULL)
 576                 fatal("rsa_generate_private_key: key generation failed.");
 577         return private;
 578 }
 579
 580 static DSA*
 581 dsa_generate_private_key(u_int bits)
 582 {
 583         DSA *private = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
 584
 585         if (private == NULL)
 586                 fatal("dsa_generate_private_key: DSA_generate_parameters failed");
 587         if (!DSA_generate_key(private))
 588                 fatal("dsa_generate_private_key: DSA_generate_key failed.");
 589         if (private == NULL)
 590                 fatal("dsa_generate_private_key: NULL.");
 591         return private;
 592 }
 593
 594 Key *
 595 key_generate(int type, u_int bits)
 596 {
 597         Key *k = key_new(KEY_UNSPEC);
 598         switch (type) {
 599         case KEY_DSA:
 600                 k->dsa = dsa_generate_private_key(bits);
 601                 break;
 602         case KEY_RSA:
 603         case KEY_RSA1:
 604                 k->rsa = rsa_generate_private_key(bits);
 605                 break;
 606         default:
 607                 fatal("key_generate: unknown type %d", type);
 608         }
 609         k->type = type;
 610         return k;
 611 }
 612
 613 Key *
 614 key_from_private(const Key *k)
 615 {
 616         Key *n = NULL;
 617         switch (k->type) {
 618         case KEY_DSA:
 619                 n = key_new(k->type);
 620                 if ((BN_copy(n->dsa->p, k->dsa->p) == NULL) ||
 621                     (BN_copy(n->dsa->q, k->dsa->q) == NULL) ||
 622                     (BN_copy(n->dsa->g, k->dsa->g) == NULL) ||
 623                     (BN_copy(n->dsa->pub_key, k->dsa->pub_key) == NULL))
 624                         fatal("key_from_private: BN_copy failed");
 625                 break;
 626         case KEY_RSA:
 627         case KEY_RSA1:
 628                 n = key_new(k->type);
 629                 if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) ||
 630                     (BN_copy(n->rsa->e, k->rsa->e) == NULL))
 631                         fatal("key_from_private: BN_copy failed");
 632                 break;
 633         default:
 634                 fatal("key_from_private: unknown type %d", k->type);
 635                 break;
 636         }
 637         return n;
 638 }
 639
 640 int
 641 key_type_from_name(char *name)
 642 {
 643         if (strcmp(name, "rsa1") == 0) {
 644                 return KEY_RSA1;
 645         } else if (strcmp(name, "rsa") == 0) {
 646                 return KEY_RSA;
 647         } else if (strcmp(name, "dsa") == 0) {
 648                 return KEY_DSA;
 649         } else if (strcmp(name, "ssh-rsa") == 0) {
 650                 return KEY_RSA;
 651         } else if (strcmp(name, "ssh-dss") == 0) {
 652                 return KEY_DSA;
 653         }
 654         debug2("key_type_from_name: unknown key type '%s'", name);
 655         return KEY_UNSPEC;
 656 }
 657
 658 int
 659 key_names_valid2(const char *names)
 660 {
 661         char *s, *cp, *p;
 662
 663         if (names == NULL || strcmp(names, "") == 0)
 664                 return 0;
 665         s = cp = xstrdup(names);
 666         for ((p = strsep(&cp, ",")); p && *p != '\0';
 667             (p = strsep(&cp, ","))) {
 668                 switch (key_type_from_name(p)) {
 669                 case KEY_RSA1:
 670                 case KEY_UNSPEC:
 671                         xfree(s);
 672                         return 0;
 673                 }
 674         }
 675         debug3("key names ok: [%s]", names);
 676         xfree(s);
 677         return 1;
 678 }
 679
 680 Key *
 681 key_from_blob(const u_char *blob, u_int blen)
 682 {
 683         Buffer b;
 684         int rlen, type;
 685         char *ktype = NULL;
 686         Key *key = NULL;
 687
 688 #ifdef DEBUG_PK
 689         dump_base64(stderr, blob, blen);
 690 #endif
 691         buffer_init(&b);
 692         buffer_append(&b, blob, blen);
 693         if ((ktype = buffer_get_string_ret(&b, NULL)) == NULL) {
 694                 error("key_from_blob: can't read key type");
 695                 goto out;
 696         }
 697
 698         type = key_type_from_name(ktype);
 699
 700         switch (type) {
 701         case KEY_RSA:
 702                 key = key_new(type);
 703                 if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 ||
 704                     buffer_get_bignum2_ret(&b, key->rsa->n) == -1) {
 705                         error("key_from_blob: can't read rsa key");
 706                         key_free(key);
 707                         key = NULL;
 708                         goto out;
 709                 }
 710 #ifdef DEBUG_PK
 711                 RSA_print_fp(stderr, key->rsa, 8);
 712 #endif
 713                 break;
 714         case KEY_DSA:
 715                 key = key_new(type);
 716                 if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 ||
 717                     buffer_get_bignum2_ret(&b, key->dsa->q) == -1 ||
 718                     buffer_get_bignum2_ret(&b, key->dsa->g) == -1 ||
 719                     buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) {
 720                         error("key_from_blob: can't read dsa key");
 721                         key_free(key);
 722                         key = NULL;
 723                         goto out;
 724                 }
 725 #ifdef DEBUG_PK
 726                 DSA_print_fp(stderr, key->dsa, 8);
 727 #endif
 728                 break;
 729         case KEY_UNSPEC:
 730                 key = key_new(type);
 731                 break;
 732         default:
 733                 error("key_from_blob: cannot handle type %s", ktype);
 734                 goto out;
 735         }
 736         rlen = buffer_len(&b);
 737         if (key != NULL && rlen != 0)
 738                 error("key_from_blob: remaining bytes in key blob %d", rlen);
 739  out:
 740         if (ktype != NULL)
 741                 xfree(ktype);
 742         buffer_free(&b);
 743         return key;
 744 }
 745
 746 int
 747 key_to_blob(const Key *key, u_char **blobp, u_int *lenp)
 748 {
 749         Buffer b;
 750         int len;
 751
 752         if (key == NULL) {
 753                 error("key_to_blob: key == NULL");
 754                 return 0;
 755         }
 756         buffer_init(&b);
 757         switch (key->type) {
 758         case KEY_DSA:
 759                 buffer_put_cstring(&b, key_ssh_name(key));
 760                 buffer_put_bignum2(&b, key->dsa->p);
 761                 buffer_put_bignum2(&b, key->dsa->q);
 762                 buffer_put_bignum2(&b, key->dsa->g);
 763                 buffer_put_bignum2(&b, key->dsa->pub_key);
 764                 break;
 765         case KEY_RSA:
 766                 buffer_put_cstring(&b, key_ssh_name(key));
 767                 buffer_put_bignum2(&b, key->rsa->e);
 768                 buffer_put_bignum2(&b, key->rsa->n);
 769                 break;
 770         default:
 771                 error("key_to_blob: unsupported key type %d", key->type);
 772                 buffer_free(&b);
 773                 return 0;
 774         }
 775         len = buffer_len(&b);
 776         if (lenp != NULL)
 777                 *lenp = len;
 778         if (blobp != NULL) {
 779                 *blobp = xmalloc(len);
 780                 memcpy(*blobp, buffer_ptr(&b), len);
 781         }
 782         memset(buffer_ptr(&b), 0, len);
 783         buffer_free(&b);
 784         return len;
 785 }
 786
 787 int
 788 key_sign(
 789     const Key *key,
 790     u_char **sigp, u_int *lenp,
 791     const u_char *data, u_int datalen)
 792 {
 793         switch (key->type) {
 794         case KEY_DSA:
 795                 return ssh_dss_sign(key, sigp, lenp, data, datalen);
 796         case KEY_RSA:
 797                 return ssh_rsa_sign(key, sigp, lenp, data, datalen);
 798         default:
 799                 error("key_sign: invalid key type %d", key->type);
 800                 return -1;
 801         }
 802 }
 803
 804 /*
 805  * key_verify returns 1 for a correct signature, 0 for an incorrect signature
 806  * and -1 on error.
 807  */
 808 int
 809 key_verify(
 810     const Key *key,
 811     const u_char *signature, u_int signaturelen,
 812     const u_char *data, u_int datalen)
 813 {
 814         if (signaturelen == 0)
 815                 return -1;
 816
 817         switch (key->type) {
 818         case KEY_DSA:
 819                 return ssh_dss_verify(key, signature, signaturelen, data, datalen);
 820         case KEY_RSA:
 821                 return ssh_rsa_verify(key, signature, signaturelen, data, datalen);
 822         default:
 823                 error("key_verify: invalid key type %d", key->type);
 824                 return -1;
 825         }
 826 }
 827
 828 /* Converts a private to a public key */
 829 Key *
 830 key_demote(const Key *k)
 831 {
 832         Key *pk;
 833
 834         pk = xcalloc(1, sizeof(*pk));
 835         pk->type = k->type;
 836         pk->flags = k->flags;
 837         pk->dsa = NULL;
 838         pk->rsa = NULL;
 839
 840         switch (k->type) {
 841         case KEY_RSA1:
 842         case KEY_RSA:
 843                 if ((pk->rsa = RSA_new()) == NULL)
 844                         fatal("key_demote: RSA_new failed");
 845                 if ((pk->rsa->e = BN_dup(k->rsa->e)) == NULL)
 846                         fatal("key_demote: BN_dup failed");
 847                 if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL)
 848                         fatal("key_demote: BN_dup failed");
 849                 break;
 850         case KEY_DSA:
 851                 if ((pk->dsa = DSA_new()) == NULL)
 852                         fatal("key_demote: DSA_new failed");
 853                 if ((pk->dsa->p = BN_dup(k->dsa->p)) == NULL)
 854                         fatal("key_demote: BN_dup failed");
 855                 if ((pk->dsa->q = BN_dup(k->dsa->q)) == NULL)
 856                         fatal("key_demote: BN_dup failed");
 857                 if ((pk->dsa->g = BN_dup(k->dsa->g)) == NULL)
 858                         fatal("key_demote: BN_dup failed");
 859                 if ((pk->dsa->pub_key = BN_dup(k->dsa->pub_key)) == NULL)
 860                         fatal("key_demote: BN_dup failed");
 861                 break;
 862         default:
 863                 fatal("key_free: bad key type %d", k->type);
 864                 break;
 865         }
 866
 867         return (pk);
 868 }