key.c

   1 /* $OpenBSD: key.c,v 1.82 2010/01/13 01:10:56 dtucker 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  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "includes.h"
  38
  39 #include <sys/param.h>
  40 #include <sys/types.h>
  41
  42 #include <openssl/evp.h>
  43 #include <openbsd-compat/openssl-compat.h>
  44
  45 #include <stdarg.h>
  46 #include <stdio.h>
  47 #include <string.h>
  48
  49 #include "xmalloc.h"
  50 #include "key.h"
  51 #include "rsa.h"
  52 #include "uuencode.h"
  53 #include "buffer.h"
  54 #include "log.h"
  55
  56 Key *
  57 key_new(int type)
  58 {
  59         Key *k;
  60         RSA *rsa;
  61         DSA *dsa;
  62         k = xcalloc(1, sizeof(*k));
  63         k->type = type;
  64         k->dsa = NULL;
  65         k->rsa = NULL;
  66         switch (k->type) {
  67         case KEY_RSA1:
  68         case KEY_RSA:
  69                 if ((rsa = RSA_new()) == NULL)
  70                         fatal("key_new: RSA_new failed");
  71                 if ((rsa->n = BN_new()) == NULL)
  72                         fatal("key_new: BN_new failed");
  73                 if ((rsa->e = BN_new()) == NULL)
  74                         fatal("key_new: BN_new failed");
  75                 k->rsa = rsa;
  76                 break;
  77         case KEY_DSA:
  78                 if ((dsa = DSA_new()) == NULL)
  79                         fatal("key_new: DSA_new failed");
  80                 if ((dsa->p = BN_new()) == NULL)
  81                         fatal("key_new: BN_new failed");
  82                 if ((dsa->q = BN_new()) == NULL)
  83                         fatal("key_new: BN_new failed");
  84                 if ((dsa->g = BN_new()) == NULL)
  85                         fatal("key_new: BN_new failed");
  86                 if ((dsa->pub_key = BN_new()) == NULL)
  87                         fatal("key_new: BN_new failed");
  88                 k->dsa = dsa;
  89                 break;
  90         case KEY_UNSPEC:
  91                 break;
  92         default:
  93                 fatal("key_new: bad key type %d", k->type);
  94                 break;
  95         }
  96         return k;
  97 }
  98
  99 Key *
 100 key_new_private(int type)
 101 {
 102         Key *k = key_new(type);
 103         switch (k->type) {
 104         case KEY_RSA1:
 105         case KEY_RSA:
 106                 if ((k->rsa->d = BN_new()) == NULL)
 107                         fatal("key_new_private: BN_new failed");
 108                 if ((k->rsa->iqmp = BN_new()) == NULL)
 109                         fatal("key_new_private: BN_new failed");
 110                 if ((k->rsa->q = BN_new()) == NULL)
 111                         fatal("key_new_private: BN_new failed");
 112                 if ((k->rsa->p = BN_new()) == NULL)
 113                         fatal("key_new_private: BN_new failed");
 114                 if ((k->rsa->dmq1 = BN_new()) == NULL)
 115                         fatal("key_new_private: BN_new failed");
 116                 if ((k->rsa->dmp1 = BN_new()) == NULL)
 117                         fatal("key_new_private: BN_new failed");
 118                 break;
 119         case KEY_DSA:
 120                 if ((k->dsa->priv_key = BN_new()) == NULL)
 121                         fatal("key_new_private: BN_new failed");
 122                 break;
 123         case KEY_UNSPEC:
 124                 break;
 125         default:
 126                 break;
 127         }
 128         return k;
 129 }
 130
 131 void
 132 key_free(Key *k)
 133 {
 134         if (k == NULL)
 135                 fatal("key_free: key is NULL");
 136         switch (k->type) {
 137         case KEY_RSA1:
 138         case KEY_RSA:
 139                 if (k->rsa != NULL)
 140                         RSA_free(k->rsa);
 141                 k->rsa = NULL;
 142                 break;
 143         case KEY_DSA:
 144                 if (k->dsa != NULL)
 145                         DSA_free(k->dsa);
 146                 k->dsa = NULL;
 147                 break;
 148         case KEY_UNSPEC:
 149                 break;
 150         default:
 151                 fatal("key_free: bad key type %d", k->type);
 152                 break;
 153         }
 154         xfree(k);
 155 }
 156
 157 int
 158 key_equal(const Key *a, const Key *b)
 159 {
 160         if (a == NULL || b == NULL || a->type != b->type)
 161                 return 0;
 162         switch (a->type) {
 163         case KEY_RSA1:
 164         case KEY_RSA:
 165                 return a->rsa != NULL && b->rsa != NULL &&
 166                     BN_cmp(a->rsa->e, b->rsa->e) == 0 &&
 167                     BN_cmp(a->rsa->n, b->rsa->n) == 0;
 168         case KEY_DSA:
 169                 return a->dsa != NULL && b->dsa != NULL &&
 170                     BN_cmp(a->dsa->p, b->dsa->p) == 0 &&
 171                     BN_cmp(a->dsa->q, b->dsa->q) == 0 &&
 172                     BN_cmp(a->dsa->g, b->dsa->g) == 0 &&
 173                     BN_cmp(a->dsa->pub_key, b->dsa->pub_key) == 0;
 174         default:
 175                 fatal("key_equal: bad key type %d", a->type);
 176         }
 177         /* NOTREACHED */
 178 }
 179
 180 u_char*
 181 key_fingerprint_raw(const Key *k, enum fp_type dgst_type,
 182     u_int *dgst_raw_length)
 183 {
 184         const EVP_MD *md = NULL;
 185         EVP_MD_CTX ctx;
 186         u_char *blob = NULL;
 187         u_char *retval = NULL;
 188         u_int len = 0;
 189         int nlen, elen;
 190
 191         *dgst_raw_length = 0;
 192
 193         switch (dgst_type) {
 194         case SSH_FP_MD5:
 195                 md = EVP_md5();
 196                 break;
 197         case SSH_FP_SHA1:
 198                 md = EVP_sha1();
 199                 break;
 200         default:
 201                 fatal("key_fingerprint_raw: bad digest type %d",
 202                     dgst_type);
 203         }
 204         switch (k->type) {
 205         case KEY_RSA1:
 206                 nlen = BN_num_bytes(k->rsa->n);
 207                 elen = BN_num_bytes(k->rsa->e);
 208                 len = nlen + elen;
 209                 blob = xmalloc(len);
 210                 BN_bn2bin(k->rsa->n, blob);
 211                 BN_bn2bin(k->rsa->e, blob + nlen);
 212                 break;
 213         case KEY_DSA:
 214         case KEY_RSA:
 215                 key_to_blob(k, &blob, &len);
 216                 break;
 217         case KEY_UNSPEC:
 218                 return retval;
 219         default:
 220                 fatal("key_fingerprint_raw: bad key type %d", k->type);
 221                 break;
 222         }
 223         if (blob != NULL) {
 224                 retval = xmalloc(EVP_MAX_MD_SIZE);
 225                 EVP_DigestInit(&ctx, md);
 226                 EVP_DigestUpdate(&ctx, blob, len);
 227                 EVP_DigestFinal(&ctx, retval, dgst_raw_length);
 228                 memset(blob, 0, len);
 229                 xfree(blob);
 230         } else {
 231                 fatal("key_fingerprint_raw: blob is null");
 232         }
 233         return retval;
 234 }
 235
 236 static char *
 237 key_fingerprint_hex(u_char *dgst_raw, u_int dgst_raw_len)
 238 {
 239         char *retval;
 240         u_int i;
 241
 242         retval = xcalloc(1, dgst_raw_len * 3 + 1);
 243         for (i = 0; i < dgst_raw_len; i++) {
 244                 char hex[4];
 245                 snprintf(hex, sizeof(hex), "%02x:", dgst_raw[i]);
 246                 strlcat(retval, hex, dgst_raw_len * 3 + 1);
 247         }
 248
 249         /* Remove the trailing ':' character */
 250         retval[(dgst_raw_len * 3) - 1] = '\0';
 251         return retval;
 252 }
 253
 254 static char *
 255 key_fingerprint_bubblebabble(u_char *dgst_raw, u_int dgst_raw_len)
 256 {
 257         char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
 258         char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
 259             'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
 260         u_int i, j = 0, rounds, seed = 1;
 261         char *retval;
 262
 263         rounds = (dgst_raw_len / 2) + 1;
 264         retval = xcalloc((rounds * 6), sizeof(char));
 265         retval[j++] = 'x';
 266         for (i = 0; i < rounds; i++) {
 267                 u_int idx0, idx1, idx2, idx3, idx4;
 268                 if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
 269                         idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
 270                             seed) % 6;
 271                         idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
 272                         idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
 273                             (seed / 6)) % 6;
 274                         retval[j++] = vowels[idx0];
 275                         retval[j++] = consonants[idx1];
 276                         retval[j++] = vowels[idx2];
 277                         if ((i + 1) < rounds) {
 278                                 idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
 279                                 idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
 280                                 retval[j++] = consonants[idx3];
 281                                 retval[j++] = '-';
 282                                 retval[j++] = consonants[idx4];
 283                                 seed = ((seed * 5) +
 284                                     ((((u_int)(dgst_raw[2 * i])) * 7) +
 285                                     ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
 286                         }
 287                 } else {
 288                         idx0 = seed % 6;
 289                         idx1 = 16;
 290                         idx2 = seed / 6;
 291                         retval[j++] = vowels[idx0];
 292                         retval[j++] = consonants[idx1];
 293                         retval[j++] = vowels[idx2];
 294                 }
 295         }
 296         retval[j++] = 'x';
 297         retval[j++] = '\0';
 298         return retval;
 299 }
 300
 301 /*
 302  * Draw an ASCII-Art representing the fingerprint so human brain can
 303  * profit from its built-in pattern recognition ability.
 304  * This technique is called "random art" and can be found in some
 305  * scientific publications like this original paper:
 306  *
 307  * "Hash Visualization: a New Technique to improve Real-World Security",
 308  * Perrig A. and Song D., 1999, International Workshop on Cryptographic
 309  * Techniques and E-Commerce (CrypTEC '99)
 310  * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
 311  *
 312  * The subject came up in a talk by Dan Kaminsky, too.
 313  *
 314  * If you see the picture is different, the key is different.
 315  * If the picture looks the same, you still know nothing.
 316  *
 317  * The algorithm used here is a worm crawling over a discrete plane,
 318  * leaving a trace (augmenting the field) everywhere it goes.
 319  * Movement is taken from dgst_raw 2bit-wise.  Bumping into walls
 320  * makes the respective movement vector be ignored for this turn.
 321  * Graphs are not unambiguous, because circles in graphs can be
 322  * walked in either direction.
 323  */
 324
 325 /*
 326  * Field sizes for the random art.  Have to be odd, so the starting point
 327  * can be in the exact middle of the picture, and FLDBASE should be >=8 .
 328  * Else pictures would be too dense, and drawing the frame would
 329  * fail, too, because the key type would not fit in anymore.
 330  */
 331 #define FLDBASE         8
 332 #define FLDSIZE_Y       (FLDBASE + 1)
 333 #define FLDSIZE_X       (FLDBASE * 2 + 1)
 334 static char *
 335 key_fingerprint_randomart(u_char *dgst_raw, u_int dgst_raw_len, const Key *k)
 336 {
 337         /*
 338          * Chars to be used after each other every time the worm
 339          * intersects with itself.  Matter of taste.
 340          */
 341         char    *augmentation_string = " .o+=*BOX@%&#/^SE";
 342         char    *retval, *p;
 343         u_char   field[FLDSIZE_X][FLDSIZE_Y];
 344         u_int    i, b;
 345         int      x, y;
 346         size_t   len = strlen(augmentation_string) - 1;
 347
 348         retval = xcalloc(1, (FLDSIZE_X + 3) * (FLDSIZE_Y + 2));
 349
 350         /* initialize field */
 351         memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
 352         x = FLDSIZE_X / 2;
 353         y = FLDSIZE_Y / 2;
 354
 355         /* process raw key */
 356         for (i = 0; i < dgst_raw_len; i++) {
 357                 int input;
 358                 /* each byte conveys four 2-bit move commands */
 359                 input = dgst_raw[i];
 360                 for (b = 0; b < 4; b++) {
 361                         /* evaluate 2 bit, rest is shifted later */
 362                         x += (input & 0x1) ? 1 : -1;
 363                         y += (input & 0x2) ? 1 : -1;
 364
 365                         /* assure we are still in bounds */
 366                         x = MAX(x, 0);
 367                         y = MAX(y, 0);
 368                         x = MIN(x, FLDSIZE_X - 1);
 369                         y = MIN(y, FLDSIZE_Y - 1);
 370
 371                         /* augment the field */
 372                         if (field[x][y] < len - 2)
 373                                 field[x][y]++;
 374                         input = input >> 2;
 375                 }
 376         }
 377
 378         /* mark starting point and end point*/
 379         field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
 380         field[x][y] = len;
 381
 382         /* fill in retval */
 383         snprintf(retval, FLDSIZE_X, "+--[%4s %4u]", key_type(k), key_size(k));
 384         p = strchr(retval, '\0');
 385
 386         /* output upper border */
 387         for (i = p - retval - 1; i < FLDSIZE_X; i++)
 388                 *p++ = '-';
 389         *p++ = '+';
 390         *p++ = '\n';
 391
 392         /* output content */
 393         for (y = 0; y < FLDSIZE_Y; y++) {
 394                 *p++ = '|';
 395                 for (x = 0; x < FLDSIZE_X; x++)
 396                         *p++ = augmentation_string[MIN(field[x][y], len)];
 397                 *p++ = '|';
 398                 *p++ = '\n';
 399         }
 400
 401         /* output lower border */
 402         *p++ = '+';
 403         for (i = 0; i < FLDSIZE_X; i++)
 404                 *p++ = '-';
 405         *p++ = '+';
 406
 407         return retval;
 408 }
 409
 410 char *
 411 key_fingerprint(const Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep)
 412 {
 413         char *retval = NULL;
 414         u_char *dgst_raw;
 415         u_int dgst_raw_len;
 416
 417         dgst_raw = key_fingerprint_raw(k, dgst_type, &dgst_raw_len);
 418         if (!dgst_raw)
 419                 fatal("key_fingerprint: null from key_fingerprint_raw()");
 420         switch (dgst_rep) {
 421         case SSH_FP_HEX:
 422                 retval = key_fingerprint_hex(dgst_raw, dgst_raw_len);
 423                 break;
 424         case SSH_FP_BUBBLEBABBLE:
 425                 retval = key_fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
 426                 break;
 427         case SSH_FP_RANDOMART:
 428                 retval = key_fingerprint_randomart(dgst_raw, dgst_raw_len, k);
 429                 break;
 430         default:
 431                 fatal("key_fingerprint: bad digest representation %d",
 432                     dgst_rep);
 433                 break;
 434         }
 435         memset(dgst_raw, 0, dgst_raw_len);
 436         xfree(dgst_raw);
 437         return retval;
 438 }
 439
 440 /*
 441  * Reads a multiple-precision integer in decimal from the buffer, and advances
 442  * the pointer.  The integer must already be initialized.  This function is
 443  * permitted to modify the buffer.  This leaves *cpp to point just beyond the
 444  * last processed (and maybe modified) character.  Note that this may modify
 445  * the buffer containing the number.
 446  */
 447 static int
 448 read_bignum(char **cpp, BIGNUM * value)
 449 {
 450         char *cp = *cpp;
 451         int old;
 452
 453         /* Skip any leading whitespace. */
 454         for (; *cp == ' ' || *cp == '\t'; cp++)
 455                 ;
 456
 457         /* Check that it begins with a decimal digit. */
 458         if (*cp < '0' || *cp > '9')
 459                 return 0;
 460
 461         /* Save starting position. */
 462         *cpp = cp;
 463
 464         /* Move forward until all decimal digits skipped. */
 465         for (; *cp >= '0' && *cp <= '9'; cp++)
 466                 ;
 467
 468         /* Save the old terminating character, and replace it by \0. */
 469         old = *cp;
 470         *cp = 0;
 471
 472         /* Parse the number. */
 473         if (BN_dec2bn(&value, *cpp) == 0)
 474                 return 0;
 475
 476         /* Restore old terminating character. */
 477         *cp = old;
 478
 479         /* Move beyond the number and return success. */
 480         *cpp = cp;
 481         return 1;
 482 }
 483
 484 static int
 485 write_bignum(FILE *f, BIGNUM *num)
 486 {
 487         char *buf = BN_bn2dec(num);
 488         if (buf == NULL) {
 489                 error("write_bignum: BN_bn2dec() failed");
 490                 return 0;
 491         }
 492         fprintf(f, " %s", buf);
 493         OPENSSL_free(buf);
 494         return 1;
 495 }
 496
 497 /* returns 1 ok, -1 error */
 498 int
 499 key_read(Key *ret, char **cpp)
 500 {
 501         Key *k;
 502         int success = -1;
 503         char *cp, *space;
 504         int len, n, type;
 505         u_int bits;
 506         u_char *blob;
 507
 508         cp = *cpp;
 509
 510         switch (ret->type) {
 511         case KEY_RSA1:
 512                 /* Get number of bits. */
 513                 if (*cp < '0' || *cp > '9')
 514                         return -1;      /* Bad bit count... */
 515                 for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
 516                         bits = 10 * bits + *cp - '0';
 517                 if (bits == 0)
 518                         return -1;
 519                 *cpp = cp;
 520                 /* Get public exponent, public modulus. */
 521                 if (!read_bignum(cpp, ret->rsa->e))
 522                         return -1;
 523                 if (!read_bignum(cpp, ret->rsa->n))
 524                         return -1;
 525                 /* validate the claimed number of bits */
 526                 if ((u_int)BN_num_bits(ret->rsa->n) != bits) {
 527                         verbose("key_read: claimed key size %d does not match "
 528                            "actual %d", bits, BN_num_bits(ret->rsa->n));
 529                         return -1;
 530                 }
 531                 success = 1;
 532                 break;
 533         case KEY_UNSPEC:
 534         case KEY_RSA:
 535         case KEY_DSA:
 536                 space = strchr(cp, ' ');
 537                 if (space == NULL) {
 538                         debug3("key_read: missing whitespace");
 539                         return -1;
 540                 }
 541                 *space = '\0';
 542                 type = key_type_from_name(cp);
 543                 *space = ' ';
 544                 if (type == KEY_UNSPEC) {
 545                         debug3("key_read: missing keytype");
 546                         return -1;
 547                 }
 548                 cp = space+1;
 549                 if (*cp == '\0') {
 550                         debug3("key_read: short string");
 551                         return -1;
 552                 }
 553                 if (ret->type == KEY_UNSPEC) {
 554                         ret->type = type;
 555                 } else if (ret->type != type) {
 556                         /* is a key, but different type */
 557                         debug3("key_read: type mismatch");
 558                         return -1;
 559                 }
 560                 len = 2*strlen(cp);
 561                 blob = xmalloc(len);
 562                 n = uudecode(cp, blob, len);
 563                 if (n < 0) {
 564                         error("key_read: uudecode %s failed", cp);
 565                         xfree(blob);
 566                         return -1;
 567                 }
 568                 k = key_from_blob(blob, (u_int)n);
 569                 xfree(blob);
 570                 if (k == NULL) {
 571                         error("key_read: key_from_blob %s failed", cp);
 572                         return -1;
 573                 }
 574                 if (k->type != type) {
 575                         error("key_read: type mismatch: encoding error");
 576                         key_free(k);
 577                         return -1;
 578                 }
 579 /*XXXX*/
 580                 if (ret->type == KEY_RSA) {
 581                         if (ret->rsa != NULL)
 582                                 RSA_free(ret->rsa);
 583                         ret->rsa = k->rsa;
 584                         k->rsa = NULL;
 585                         success = 1;
 586 #ifdef DEBUG_PK
 587                         RSA_print_fp(stderr, ret->rsa, 8);
 588 #endif
 589                 } else {
 590                         if (ret->dsa != NULL)
 591                                 DSA_free(ret->dsa);
 592                         ret->dsa = k->dsa;
 593                         k->dsa = NULL;
 594                         success = 1;
 595 #ifdef DEBUG_PK
 596                         DSA_print_fp(stderr, ret->dsa, 8);
 597 #endif
 598                 }
 599 /*XXXX*/
 600                 key_free(k);
 601                 if (success != 1)
 602                         break;
 603                 /* advance cp: skip whitespace and data */
 604                 while (*cp == ' ' || *cp == '\t')
 605                         cp++;
 606                 while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 607                         cp++;
 608                 *cpp = cp;
 609                 break;
 610         default:
 611                 fatal("key_read: bad key type: %d", ret->type);
 612                 break;
 613         }
 614         return success;
 615 }
 616
 617 int
 618 key_write(const Key *key, FILE *f)
 619 {
 620         int n, success = 0;
 621         u_int len, bits = 0;
 622         u_char *blob;
 623         char *uu;
 624
 625         if (key->type == KEY_RSA1 && key->rsa != NULL) {
 626                 /* size of modulus 'n' */
 627                 bits = BN_num_bits(key->rsa->n);
 628                 fprintf(f, "%u", bits);
 629                 if (write_bignum(f, key->rsa->e) &&
 630                     write_bignum(f, key->rsa->n)) {
 631                         success = 1;
 632                 } else {
 633                         error("key_write: failed for RSA key");
 634                 }
 635         } else if ((key->type == KEY_DSA && key->dsa != NULL) ||
 636             (key->type == KEY_RSA && key->rsa != NULL)) {
 637                 key_to_blob(key, &blob, &len);
 638                 uu = xmalloc(2*len);
 639                 n = uuencode(blob, len, uu, 2*len);
 640                 if (n > 0) {
 641                         fprintf(f, "%s %s", key_ssh_name(key), uu);
 642                         success = 1;
 643                 }
 644                 xfree(blob);
 645                 xfree(uu);
 646         }
 647         return success;
 648 }
 649
 650 const char *
 651 key_type(const Key *k)
 652 {
 653         switch (k->type) {
 654         case KEY_RSA1:
 655                 return "RSA1";
 656         case KEY_RSA:
 657                 return "RSA";
 658         case KEY_DSA:
 659                 return "DSA";
 660         }
 661         return "unknown";
 662 }
 663
 664 const char *
 665 key_ssh_name(const Key *k)
 666 {
 667         switch (k->type) {
 668         case KEY_RSA:
 669                 return "ssh-rsa";
 670         case KEY_DSA:
 671                 return "ssh-dss";
 672         }
 673         return "ssh-unknown";
 674 }
 675
 676 u_int
 677 key_size(const Key *k)
 678 {
 679         switch (k->type) {
 680         case KEY_RSA1:
 681         case KEY_RSA:
 682                 return BN_num_bits(k->rsa->n);
 683         case KEY_DSA:
 684                 return BN_num_bits(k->dsa->p);
 685         }
 686         return 0;
 687 }
 688
 689 static RSA *
 690 rsa_generate_private_key(u_int bits)
 691 {
 692         RSA *private;
 693
 694         private = RSA_generate_key(bits, RSA_F4, NULL, NULL);
 695         if (private == NULL)
 696                 fatal("rsa_generate_private_key: key generation failed.");
 697         return private;
 698 }
 699
 700 static DSA*
 701 dsa_generate_private_key(u_int bits)
 702 {
 703         DSA *private = DSA_generate_parameters(bits, NULL, 0, NULL, NULL, NULL, NULL);
 704
 705         if (private == NULL)
 706                 fatal("dsa_generate_private_key: DSA_generate_parameters failed");
 707         if (!DSA_generate_key(private))
 708                 fatal("dsa_generate_private_key: DSA_generate_key failed.");
 709         if (private == NULL)
 710                 fatal("dsa_generate_private_key: NULL.");
 711         return private;
 712 }
 713
 714 Key *
 715 key_generate(int type, u_int bits)
 716 {
 717         Key *k = key_new(KEY_UNSPEC);
 718         switch (type) {
 719         case KEY_DSA:
 720                 k->dsa = dsa_generate_private_key(bits);
 721                 break;
 722         case KEY_RSA:
 723         case KEY_RSA1:
 724                 k->rsa = rsa_generate_private_key(bits);
 725                 break;
 726         default:
 727                 fatal("key_generate: unknown type %d", type);
 728         }
 729         k->type = type;
 730         return k;
 731 }
 732
 733 Key *
 734 key_from_private(const Key *k)
 735 {
 736         Key *n = NULL;
 737         switch (k->type) {
 738         case KEY_DSA:
 739                 n = key_new(k->type);
 740                 if ((BN_copy(n->dsa->p, k->dsa->p) == NULL) ||
 741                     (BN_copy(n->dsa->q, k->dsa->q) == NULL) ||
 742                     (BN_copy(n->dsa->g, k->dsa->g) == NULL) ||
 743                     (BN_copy(n->dsa->pub_key, k->dsa->pub_key) == NULL))
 744                         fatal("key_from_private: BN_copy failed");
 745                 break;
 746         case KEY_RSA:
 747         case KEY_RSA1:
 748                 n = key_new(k->type);
 749                 if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) ||
 750                     (BN_copy(n->rsa->e, k->rsa->e) == NULL))
 751                         fatal("key_from_private: BN_copy failed");
 752                 break;
 753         default:
 754                 fatal("key_from_private: unknown type %d", k->type);
 755                 break;
 756         }
 757         return n;
 758 }
 759
 760 int
 761 key_type_from_name(char *name)
 762 {
 763         if (strcmp(name, "rsa1") == 0) {
 764                 return KEY_RSA1;
 765         } else if (strcmp(name, "rsa") == 0) {
 766                 return KEY_RSA;
 767         } else if (strcmp(name, "dsa") == 0) {
 768                 return KEY_DSA;
 769         } else if (strcmp(name, "ssh-rsa") == 0) {
 770                 return KEY_RSA;
 771         } else if (strcmp(name, "ssh-dss") == 0) {
 772                 return KEY_DSA;
 773         }
 774         debug2("key_type_from_name: unknown key type '%s'", name);
 775         return KEY_UNSPEC;
 776 }
 777
 778 int
 779 key_names_valid2(const char *names)
 780 {
 781         char *s, *cp, *p;
 782
 783         if (names == NULL || strcmp(names, "") == 0)
 784                 return 0;
 785         s = cp = xstrdup(names);
 786         for ((p = strsep(&cp, ",")); p && *p != '\0';
 787             (p = strsep(&cp, ","))) {
 788                 switch (key_type_from_name(p)) {
 789                 case KEY_RSA1:
 790                 case KEY_UNSPEC:
 791                         xfree(s);
 792                         return 0;
 793                 }
 794         }
 795         debug3("key names ok: [%s]", names);
 796         xfree(s);
 797         return 1;
 798 }
 799
 800 Key *
 801 key_from_blob(const u_char *blob, u_int blen)
 802 {
 803         Buffer b;
 804         int rlen, type;
 805         char *ktype = NULL;
 806         Key *key = NULL;
 807
 808 #ifdef DEBUG_PK
 809         dump_base64(stderr, blob, blen);
 810 #endif
 811         buffer_init(&b);
 812         buffer_append(&b, blob, blen);
 813         if ((ktype = buffer_get_string_ret(&b, NULL)) == NULL) {
 814                 error("key_from_blob: can't read key type");
 815                 goto out;
 816         }
 817
 818         type = key_type_from_name(ktype);
 819
 820         switch (type) {
 821         case KEY_RSA:
 822                 key = key_new(type);
 823                 if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 ||
 824                     buffer_get_bignum2_ret(&b, key->rsa->n) == -1) {
 825                         error("key_from_blob: can't read rsa key");
 826                         key_free(key);
 827                         key = NULL;
 828                         goto out;
 829                 }
 830 #ifdef DEBUG_PK
 831                 RSA_print_fp(stderr, key->rsa, 8);
 832 #endif
 833                 break;
 834         case KEY_DSA:
 835                 key = key_new(type);
 836                 if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 ||
 837                     buffer_get_bignum2_ret(&b, key->dsa->q) == -1 ||
 838                     buffer_get_bignum2_ret(&b, key->dsa->g) == -1 ||
 839                     buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) {
 840                         error("key_from_blob: can't read dsa key");
 841                         key_free(key);
 842                         key = NULL;
 843                         goto out;
 844                 }
 845 #ifdef DEBUG_PK
 846                 DSA_print_fp(stderr, key->dsa, 8);
 847 #endif
 848                 break;
 849         case KEY_UNSPEC:
 850                 key = key_new(type);
 851                 break;
 852         default:
 853                 error("key_from_blob: cannot handle type %s", ktype);
 854                 goto out;
 855         }
 856         rlen = buffer_len(&b);
 857         if (key != NULL && rlen != 0)
 858                 error("key_from_blob: remaining bytes in key blob %d", rlen);
 859  out:
 860         if (ktype != NULL)
 861                 xfree(ktype);
 862         buffer_free(&b);
 863         return key;
 864 }
 865
 866 int
 867 key_to_blob(const Key *key, u_char **blobp, u_int *lenp)
 868 {
 869         Buffer b;
 870         int len;
 871
 872         if (key == NULL) {
 873                 error("key_to_blob: key == NULL");
 874                 return 0;
 875         }
 876         buffer_init(&b);
 877         switch (key->type) {
 878         case KEY_DSA:
 879                 buffer_put_cstring(&b, key_ssh_name(key));
 880                 buffer_put_bignum2(&b, key->dsa->p);
 881                 buffer_put_bignum2(&b, key->dsa->q);
 882                 buffer_put_bignum2(&b, key->dsa->g);
 883                 buffer_put_bignum2(&b, key->dsa->pub_key);
 884                 break;
 885         case KEY_RSA:
 886                 buffer_put_cstring(&b, key_ssh_name(key));
 887                 buffer_put_bignum2(&b, key->rsa->e);
 888                 buffer_put_bignum2(&b, key->rsa->n);
 889                 break;
 890         default:
 891                 error("key_to_blob: unsupported key type %d", key->type);
 892                 buffer_free(&b);
 893                 return 0;
 894         }
 895         len = buffer_len(&b);
 896         if (lenp != NULL)
 897                 *lenp = len;
 898         if (blobp != NULL) {
 899                 *blobp = xmalloc(len);
 900                 memcpy(*blobp, buffer_ptr(&b), len);
 901         }
 902         memset(buffer_ptr(&b), 0, len);
 903         buffer_free(&b);
 904         return len;
 905 }
 906
 907 int
 908 key_sign(
 909     const Key *key,
 910     u_char **sigp, u_int *lenp,
 911     const u_char *data, u_int datalen)
 912 {
 913         switch (key->type) {
 914         case KEY_DSA:
 915                 return ssh_dss_sign(key, sigp, lenp, data, datalen);
 916         case KEY_RSA:
 917                 return ssh_rsa_sign(key, sigp, lenp, data, datalen);
 918         default:
 919                 error("key_sign: invalid key type %d", key->type);
 920                 return -1;
 921         }
 922 }
 923
 924 /*
 925  * key_verify returns 1 for a correct signature, 0 for an incorrect signature
 926  * and -1 on error.
 927  */
 928 int
 929 key_verify(
 930     const Key *key,
 931     const u_char *signature, u_int signaturelen,
 932     const u_char *data, u_int datalen)
 933 {
 934         if (signaturelen == 0)
 935                 return -1;
 936
 937         switch (key->type) {
 938         case KEY_DSA:
 939                 return ssh_dss_verify(key, signature, signaturelen, data, datalen);
 940         case KEY_RSA:
 941                 return ssh_rsa_verify(key, signature, signaturelen, data, datalen);
 942         default:
 943                 error("key_verify: invalid key type %d", key->type);
 944                 return -1;
 945         }
 946 }
 947
 948 /* Converts a private to a public key */
 949 Key *
 950 key_demote(const Key *k)
 951 {
 952         Key *pk;
 953
 954         pk = xcalloc(1, sizeof(*pk));
 955         pk->type = k->type;
 956         pk->flags = k->flags;
 957         pk->dsa = NULL;
 958         pk->rsa = NULL;
 959
 960         switch (k->type) {
 961         case KEY_RSA1:
 962         case KEY_RSA:
 963                 if ((pk->rsa = RSA_new()) == NULL)
 964                         fatal("key_demote: RSA_new failed");
 965                 if ((pk->rsa->e = BN_dup(k->rsa->e)) == NULL)
 966                         fatal("key_demote: BN_dup failed");
 967                 if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL)
 968                         fatal("key_demote: BN_dup failed");
 969                 break;
 970         case KEY_DSA:
 971                 if ((pk->dsa = DSA_new()) == NULL)
 972                         fatal("key_demote: DSA_new failed");
 973                 if ((pk->dsa->p = BN_dup(k->dsa->p)) == NULL)
 974                         fatal("key_demote: BN_dup failed");
 975                 if ((pk->dsa->q = BN_dup(k->dsa->q)) == NULL)
 976                         fatal("key_demote: BN_dup failed");
 977                 if ((pk->dsa->g = BN_dup(k->dsa->g)) == NULL)
 978                         fatal("key_demote: BN_dup failed");
 979                 if ((pk->dsa->pub_key = BN_dup(k->dsa->pub_key)) == NULL)
 980                         fatal("key_demote: BN_dup failed");
 981                 break;
 982         default:
 983                 fatal("key_free: bad key type %d", k->type);
 984                 break;
 985         }
 986
 987         return (pk);
 988 }