1 /*- 2 * Copyright (c) 2009 The NetBSD Foundation, Inc. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to The NetBSD Foundation 6 * by Alistair Crooks (agc@NetBSD.org) 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 27 * POSSIBILITY OF SUCH DAMAGE. 28 */ 29 #include "config.h" 30 31 #ifdef HAVE_SYS_CDEFS_H 32 #include <sys/cdefs.h> 33 #endif 34 35 #include <sys/types.h> 36 #include <sys/stat.h> 37 #include <sys/param.h> 38 39 #include <netinet/in.h> 40 41 #include <arpa/inet.h> 42 43 #include <ctype.h> 44 #include <inttypes.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #ifdef HAVE_UNISTD_H 50 #include <unistd.h> 51 #endif 52 53 #ifdef HAVE_LIMITS_H 54 #include <limits.h> 55 #endif 56 57 #ifdef HAVE_OPENSSL_CAST_H 58 #include <openssl/cast.h> 59 #endif 60 61 #include <openssl/pem.h> 62 63 #include "bufgap.h" 64 65 #include "packet-parse.h" 66 #include "netpgpdefs.h" 67 #include "netpgpsdk.h" 68 #include "crypto.h" 69 #include "netpgpdigest.h" 70 #include "ssh2pgp.h" 71 72 /* structure for earching for constant strings */ 73 typedef struct str_t { 74 const char *s; /* string */ 75 size_t len; /* its length */ 76 int type; /* return type */ 77 } str_t; 78 79 #ifndef USE_ARG 80 #define USE_ARG(x) /*LINTED*/(void)&x 81 #endif 82 83 static const uint8_t base64s[] = 84 /* 000 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 85 /* 016 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 86 /* 032 */ "\0\0\0\0\0\0\0\0\0\0\0?\0\0\0@" 87 /* 048 */ "56789:;<=>\0\0\0\0\0\0" 88 /* 064 */ "\0\1\2\3\4\5\6\7\10\11\12\13\14\15\16\17" 89 /* 080 */ "\20\21\22\23\24\25\26\27\30\31\32\0\0\0\0\0" 90 /* 096 */ "\0\33\34\35\36\37 !\"#$%&'()" 91 /* 112 */ "*+,-./01234\0\0\0\0\0" 92 /* 128 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 93 /* 144 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 94 /* 160 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 95 /* 176 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 96 /* 192 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 97 /* 208 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 98 /* 224 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 99 /* 240 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 100 101 102 /* short function to decode from base64 */ 103 /* inspired by an ancient copy of b64.c, then rewritten, the bugs are all mine */ 104 static int 105 frombase64(char *dst, const char *src, size_t size, int flag) 106 { 107 uint8_t out[3]; 108 uint8_t in[4]; 109 uint8_t b; 110 size_t srcc; 111 int dstc; 112 int gotc; 113 int i; 114 115 USE_ARG(flag); 116 for (dstc = 0, srcc = 0 ; srcc < size; ) { 117 for (gotc = 0, i = 0; i < 4 && srcc < size; i++) { 118 for (b = 0x0; srcc < size && b == 0x0 ; ) { 119 b = base64s[(unsigned)src[srcc++]]; 120 } 121 if (srcc < size) { 122 gotc += 1; 123 if (b) { 124 in[i] = (uint8_t)(b - 1); 125 } 126 } else { 127 in[i] = 0x0; 128 } 129 } 130 if (gotc) { 131 out[0] = (uint8_t)((unsigned)in[0] << 2 | 132 (unsigned)in[1] >> 4); 133 out[1] = (uint8_t)((unsigned)in[1] << 4 | 134 (unsigned)in[2] >> 2); 135 out[2] = (uint8_t)(((in[2] << 6) & 0xc0) | in[3]); 136 for (i = 0; i < gotc - 1; i++) { 137 *dst++ = out[i]; 138 } 139 dstc += gotc - 1; 140 } 141 } 142 return dstc; 143 } 144 145 /* get a bignum from the buffer gap */ 146 static BIGNUM * 147 getbignum(bufgap_t *bg, char *buf, const char *header) 148 { 149 uint32_t len; 150 BIGNUM *bignum; 151 152 (void) bufgap_getbin(bg, &len, sizeof(len)); 153 len = ntohl(len); 154 (void) bufgap_seek(bg, sizeof(len), BGFromHere, BGByte); 155 (void) bufgap_getbin(bg, buf, len); 156 bignum = BN_bin2bn((const uint8_t *)buf, (int)len, NULL); 157 if (pgp_get_debug_level(__FILE__)) { 158 hexdump(stderr, header, (const uint8_t *)(void *)buf, len); 159 } 160 (void) bufgap_seek(bg, len, BGFromHere, BGByte); 161 return bignum; 162 } 163 164 #if 0 165 static int 166 putbignum(bufgap_t *bg, BIGNUM *bignum) 167 { 168 uint32_t len; 169 170 len = BN_num_bytes(bignum); 171 (void) bufgap_insert(bg, &len, sizeof(len)); 172 (void) bufgap_insert(bg, buf, len); 173 bignum = BN_bin2bn((const uint8_t *)buf, (int)len, NULL); 174 if (pgp_get_debug_level(__FILE__)) { 175 hexdump(stderr, header, buf, (int)len); 176 } 177 (void) bufgap_seek(bg, len, BGFromHere, BGByte); 178 return bignum; 179 } 180 #endif 181 182 static str_t pkatypes[] = { 183 { "ssh-rsa", 7, PGP_PKA_RSA }, 184 { "ssh-dss", 7, PGP_PKA_DSA }, 185 { "ssh-dsa", 7, PGP_PKA_DSA }, 186 { NULL, 0, 0 } 187 }; 188 189 /* look for a string in the given array */ 190 static int 191 findstr(str_t *array, const char *name) 192 { 193 str_t *sp; 194 195 for (sp = array ; sp->s ; sp++) { 196 if (strncmp(name, sp->s, sp->len) == 0) { 197 return sp->type; 198 } 199 } 200 return -1; 201 } 202 203 /* convert an ssh (host) pubkey to a pgp pubkey */ 204 int 205 pgp_ssh2pubkey(pgp_io_t *io, const char *f, pgp_key_t *key, pgp_hash_alg_t hashtype) 206 { 207 pgp_pubkey_t *pubkey; 208 struct stat st; 209 bufgap_t bg; 210 uint32_t len; 211 int64_t off; 212 uint8_t *userid; 213 char hostname[256]; 214 char owner[256]; 215 char *space; 216 char *buf; 217 char *bin; 218 int ok; 219 int cc; 220 221 (void) memset(&bg, 0x0, sizeof(bg)); 222 if (!bufgap_open(&bg, f)) { 223 (void) fprintf(stderr, "pgp_ssh2pubkey: can't open '%s'\n", f); 224 return 0; 225 } 226 (void)stat(f, &st); 227 if ((buf = calloc(1, (size_t)st.st_size)) == NULL) { 228 (void) fprintf(stderr, "can't calloc %zu bytes for '%s'\n", (size_t)st.st_size, f); 229 bufgap_close(&bg); 230 return 0; 231 } 232 if ((bin = calloc(1, (size_t)st.st_size)) == NULL) { 233 (void) fprintf(stderr, "can't calloc %zu bytes for '%s'\n", (size_t)st.st_size, f); 234 (void) free(buf); 235 bufgap_close(&bg); 236 return 0; 237 } 238 239 /* move past ascii type of key */ 240 while (bufgap_peek(&bg, 0) != ' ') { 241 bufgap_seek(&bg, 1, BGFromHere, BGByte); 242 } 243 bufgap_seek(&bg, 1, BGFromHere, BGByte); 244 off = bufgap_tell(&bg, BGFromBOF, BGByte); 245 246 if (bufgap_size(&bg, BGByte) - off < 10) { 247 (void) fprintf(stderr, "bad key file '%s'\n", f); 248 (void) free(buf); 249 bufgap_close(&bg); 250 return 0; 251 } 252 253 /* convert from base64 to binary */ 254 cc = bufgap_getbin(&bg, buf, (size_t)bg.bcc); 255 if ((space = strchr(buf, ' ')) != NULL) { 256 cc = (int)(space - buf); 257 } 258 if (pgp_get_debug_level(__FILE__)) { 259 hexdump(stderr, NULL, (const uint8_t *)(const void *)buf, (size_t)cc); 260 } 261 cc = frombase64(bin, buf, (size_t)cc, 0); 262 if (pgp_get_debug_level(__FILE__)) { 263 hexdump(stderr, "decoded base64:", (const uint8_t *)(const void *)bin, (size_t)cc); 264 } 265 bufgap_delete(&bg, (uint64_t)bufgap_tell(&bg, BGFromEOF, BGByte)); 266 bufgap_insert(&bg, bin, cc); 267 bufgap_seek(&bg, off, BGFromBOF, BGByte); 268 269 /* get the type of key */ 270 (void) bufgap_getbin(&bg, &len, sizeof(len)); 271 len = ntohl(len); 272 (void) bufgap_seek(&bg, sizeof(len), BGFromHere, BGByte); 273 (void) bufgap_getbin(&bg, buf, len); 274 (void) bufgap_seek(&bg, len, BGFromHere, BGByte); 275 276 (void) memset(key, 0x0, sizeof(*key)); 277 pubkey = &key->key.seckey.pubkey; 278 pubkey->version = PGP_V4; 279 pubkey->birthtime = 0; 280 /* get key type */ 281 ok = 1; 282 switch (pubkey->alg = findstr(pkatypes, buf)) { 283 case PGP_PKA_RSA: 284 /* get the 'e' param of the key */ 285 pubkey->key.rsa.e = getbignum(&bg, buf, "RSA E"); 286 /* get the 'n' param of the key */ 287 pubkey->key.rsa.n = getbignum(&bg, buf, "RSA N"); 288 break; 289 case PGP_PKA_DSA: 290 /* get the 'p' param of the key */ 291 pubkey->key.dsa.p = getbignum(&bg, buf, "DSA P"); 292 /* get the 'q' param of the key */ 293 pubkey->key.dsa.q = getbignum(&bg, buf, "DSA Q"); 294 /* get the 'g' param of the key */ 295 pubkey->key.dsa.g = getbignum(&bg, buf, "DSA G"); 296 /* get the 'y' param of the key */ 297 pubkey->key.dsa.y = getbignum(&bg, buf, "DSA Y"); 298 break; 299 default: 300 (void) fprintf(stderr, "Unrecognised pubkey type %d for '%s'\n", 301 pubkey->alg, f); 302 ok = 0; 303 break; 304 } 305 306 /* check for stragglers */ 307 if (ok && bufgap_tell(&bg, BGFromEOF, BGByte) > 0) { 308 printf("%"PRIi64" bytes left\n", bufgap_tell(&bg, BGFromEOF, BGByte)); 309 printf("[%s]\n", bufgap_getstr(&bg)); 310 ok = 0; 311 } 312 if (ok) { 313 (void) memset(&userid, 0x0, sizeof(userid)); 314 (void) gethostname(hostname, sizeof(hostname)); 315 if (strlen(space + 1) - 1 == 0) { 316 (void) snprintf(owner, sizeof(owner), "<root@%s>", 317 hostname); 318 } else { 319 (void) snprintf(owner, sizeof(owner), "<%.*s>", 320 (int)strlen(space + 1) - 1, 321 space + 1); 322 } 323 (void) pgp_asprintf((char **)(void *)&userid, 324 "%s (%s) %s", 325 hostname, 326 f, 327 owner); 328 pgp_keyid(key->sigid, sizeof(key->sigid), pubkey, hashtype); 329 pgp_add_userid(key, userid); 330 pgp_fingerprint(&key->sigfingerprint, pubkey, hashtype); 331 free(userid); 332 if (pgp_get_debug_level(__FILE__)) { 333 /*pgp_print_keydata(io, keyring, key, "pub", pubkey, 0);*/ 334 __PGP_USED(io); /* XXX */ 335 } 336 } 337 (void) free(bin); 338 (void) free(buf); 339 bufgap_close(&bg); 340 return ok; 341 } 342 343 /* convert an ssh (host) seckey to a pgp seckey */ 344 int 345 pgp_ssh2seckey(pgp_io_t *io, const char *f, pgp_key_t *key, pgp_pubkey_t *pubkey, pgp_hash_alg_t hashtype) 346 { 347 pgp_crypt_t crypted; 348 pgp_hash_t hash; 349 unsigned done = 0; 350 unsigned i = 0; 351 uint8_t sesskey[CAST_KEY_LENGTH]; 352 uint8_t hashed[PGP_SHA1_HASH_SIZE]; 353 BIGNUM *tmp; 354 355 __PGP_USED(io); 356 /* XXX - check for rsa/dsa */ 357 if (!openssl_read_pem_seckey(f, key, "ssh-rsa", 0)) { 358 return 0; 359 } 360 if (pgp_get_debug_level(__FILE__)) { 361 /*pgp_print_keydata(io, key, "sec", &key->key.seckey.pubkey, 0);*/ 362 /* XXX */ 363 } 364 /* let's add some sane defaults */ 365 (void) memcpy(&key->key.seckey.pubkey, pubkey, sizeof(*pubkey)); 366 key->key.seckey.s2k_usage = PGP_S2KU_ENCRYPTED_AND_HASHED; 367 key->key.seckey.alg = PGP_SA_CAST5; 368 key->key.seckey.s2k_specifier = PGP_S2KS_SALTED; 369 key->key.seckey.hash_alg = PGP_HASH_SHA1; 370 if (key->key.seckey.pubkey.alg == PGP_PKA_RSA) { 371 /* openssh and openssl have p and q swapped */ 372 tmp = key->key.seckey.key.rsa.p; 373 key->key.seckey.key.rsa.p = key->key.seckey.key.rsa.q; 374 key->key.seckey.key.rsa.q = tmp; 375 } 376 for (done = 0, i = 0; done < CAST_KEY_LENGTH; i++) { 377 unsigned j; 378 uint8_t zero = 0; 379 int needed; 380 int size; 381 382 needed = CAST_KEY_LENGTH - done; 383 size = MIN(needed, PGP_SHA1_HASH_SIZE); 384 385 pgp_hash_any(&hash, key->key.seckey.hash_alg); 386 if (!hash.init(&hash)) { 387 (void) fprintf(stderr, "write_seckey_body: bad alloc\n"); 388 return 0; 389 } 390 391 /* preload if iterating */ 392 for (j = 0; j < i; j++) { 393 /* 394 * Coverity shows a DEADCODE error on this 395 * line. This is expected since the hardcoded 396 * use of SHA1 and CAST5 means that it will 397 * not used. This will change however when 398 * other algorithms are supported. 399 */ 400 hash.add(&hash, &zero, 1); 401 } 402 403 if (key->key.seckey.s2k_specifier == PGP_S2KS_SALTED) { 404 hash.add(&hash, key->key.seckey.salt, PGP_SALT_SIZE); 405 } 406 hash.finish(&hash, hashed); 407 408 /* 409 * if more in hash than is needed by session key, use 410 * the leftmost octets 411 */ 412 (void) memcpy(&sesskey[i * PGP_SHA1_HASH_SIZE], 413 hashed, (unsigned)size); 414 done += (unsigned)size; 415 if (done > CAST_KEY_LENGTH) { 416 (void) fprintf(stderr, 417 "write_seckey_body: short add\n"); 418 return 0; 419 } 420 } 421 pgp_crypt_any(&crypted, key->key.seckey.alg); 422 crypted.set_iv(&crypted, key->key.seckey.iv); 423 crypted.set_crypt_key(&crypted, sesskey); 424 pgp_encrypt_init(&crypted); 425 key->key.seckey.pubkey.alg = PGP_PKA_RSA; 426 pgp_fingerprint(&key->sigfingerprint, pubkey, hashtype); 427 pgp_keyid(key->sigid, sizeof(key->sigid), pubkey, hashtype); 428 return 1; 429 } 430 431 /* read a key from the ssh file, and add it to a keyring */ 432 int 433 pgp_ssh2_readkeys(pgp_io_t *io, pgp_keyring_t *pubring, 434 pgp_keyring_t *secring, const char *pubfile, 435 const char *secfile, unsigned hashtype) 436 { 437 pgp_key_t *pubkey; 438 pgp_key_t *seckey; 439 pgp_key_t key; 440 441 pubkey = NULL; 442 (void) memset(&key, 0x0, sizeof(key)); 443 if (pubfile) { 444 if (pgp_get_debug_level(__FILE__)) { 445 (void) fprintf(io->errs, "pgp_ssh2_readkeys: pubfile '%s'\n", pubfile); 446 } 447 if (!pgp_ssh2pubkey(io, pubfile, &key, (pgp_hash_alg_t)hashtype)) { 448 (void) fprintf(io->errs, "pgp_ssh2_readkeys: can't read pubkeys '%s'\n", pubfile); 449 return 0; 450 } 451 EXPAND_ARRAY(pubring, key); 452 pubkey = &pubring->keys[pubring->keyc++]; 453 (void) memcpy(pubkey, &key, sizeof(key)); 454 pubkey->type = PGP_PTAG_CT_PUBLIC_KEY; 455 } 456 if (secfile) { 457 if (pgp_get_debug_level(__FILE__)) { 458 (void) fprintf(io->errs, "pgp_ssh2_readkeys: secfile '%s'\n", secfile); 459 } 460 if (pubkey == NULL) { 461 pubkey = &pubring->keys[0]; 462 } 463 if (!pgp_ssh2seckey(io, secfile, &key, &pubkey->key.pubkey, (pgp_hash_alg_t)hashtype)) { 464 (void) fprintf(io->errs, "pgp_ssh2_readkeys: can't read seckeys '%s'\n", secfile); 465 return 0; 466 } 467 EXPAND_ARRAY(secring, key); 468 seckey = &secring->keys[secring->keyc++]; 469 (void) memcpy(seckey, &key, sizeof(key)); 470 seckey->type = PGP_PTAG_CT_SECRET_KEY; 471 } 472 return 1; 473 } 474