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 <inttypes.h> 40 41 /* this brings in the prototype for asprintf on Linux */ 42 #define _GNU_SOURCE 43 #include <stdio.h> 44 45 #include <stdlib.h> 46 #include <string.h> 47 48 #ifdef HAVE_UNISTD_H 49 #include <unistd.h> 50 #endif 51 52 #ifdef HAVE_LIMITS_H 53 #include <limits.h> 54 #endif 55 56 #ifdef HAVE_OPENSSL_CAST_H 57 #include <openssl/cast.h> 58 #endif 59 60 #include <openssl/pem.h> 61 62 #include "bufgap.h" 63 #include "fastctype.h" 64 65 #include "packet-parse.h" 66 #include "netpgpdefs.h" 67 #include "crypto.h" 68 #include "netpgpdigest.h" 69 #include "ops-ssh.h" 70 71 /* structure for earching for constant strings */ 72 typedef struct str_t { 73 const char *s; /* string */ 74 size_t len; /* its length */ 75 int type; /* return type */ 76 } str_t; 77 78 #ifndef USE_ARG 79 #define USE_ARG(x) /*LINTED*/(void)&x 80 #endif 81 82 static const uint8_t base64s[] = 83 /* 000 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 84 /* 016 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 85 /* 032 */ "\0\0\0\0\0\0\0\0\0\0\0?\0\0\0@" 86 /* 048 */ "56789:;<=>\0\0\0\0\0\0" 87 /* 064 */ "\0\1\2\3\4\5\6\7\10\11\12\13\14\15\16\17" 88 /* 080 */ "\20\21\22\23\24\25\26\27\30\31\32\0\0\0\0\0" 89 /* 096 */ "\0\33\34\35\36\37 !\"#$%&'()" 90 /* 112 */ "*+,-./01234\0\0\0\0\0" 91 /* 128 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 92 /* 144 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 93 /* 160 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 94 /* 176 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 95 /* 192 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 96 /* 208 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 97 /* 224 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0" 98 /* 240 */ "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; 99 100 101 /* short function to decode from base64 */ 102 /* inspired by an ancient copy of b64.c, then rewritten, the bugs are all mine */ 103 static int 104 frombase64(char *dst, const char *src, size_t size, int flag) 105 { 106 uint8_t out[3]; 107 uint8_t in[4]; 108 uint8_t b; 109 size_t srcc; 110 int dstc; 111 int gotc; 112 int i; 113 114 USE_ARG(flag); 115 for (dstc = 0, srcc = 0 ; srcc < size; ) { 116 for (gotc = 0, i = 0; i < 4 && srcc < size; i++) { 117 for (b = 0x0; srcc < size && b == 0x0 ; ) { 118 b = base64s[(unsigned)src[srcc++]]; 119 } 120 if (srcc < size) { 121 gotc += 1; 122 if (b) { 123 in[i] = (uint8_t)(b - 1); 124 } 125 } else { 126 in[i] = 0x0; 127 } 128 } 129 if (gotc) { 130 out[0] = (uint8_t)((unsigned)in[0] << 2 | 131 (unsigned)in[1] >> 4); 132 out[1] = (uint8_t)((unsigned)in[1] << 4 | 133 (unsigned)in[2] >> 2); 134 out[2] = (uint8_t)(((in[2] << 6) & 0xc0) | in[3]); 135 for (i = 0; i < gotc - 1; i++) { 136 *dst++ = out[i]; 137 } 138 dstc += gotc - 1; 139 } 140 } 141 return dstc; 142 } 143 144 #define LINELEN 16 145 146 /* show hexadecimal/ascii dump */ 147 static void 148 show(const char *header, char *in, int len) 149 { 150 char line[LINELEN + 1]; 151 int i; 152 153 printf("%s%s", (header) ? header : "", (header) ? "\n" : ""); 154 printf("[%d chars]\n", len); 155 for (i = 0 ; i < len ; i++) { 156 if (i % LINELEN == 0) { 157 printf("%.5d | ", i); 158 } 159 printf("%.02x ", (uint8_t)in[i]); 160 line[i % LINELEN] = (isprint(in[i])) ? in[i] : '.'; 161 if (i % LINELEN == LINELEN - 1) { 162 line[LINELEN] = 0x0; 163 printf(" | %s\n", line); 164 } 165 } 166 for ( ; i % LINELEN != 0 ; i++) { 167 printf(" "); 168 line[i % LINELEN] = ' '; 169 } 170 line[LINELEN] = 0x0; 171 printf(" | %s\n", line); 172 } 173 174 /* get a bignum from the buffer gap */ 175 static BIGNUM * 176 getbignum(bufgap_t *bg, char *buf, const char *header) 177 { 178 uint32_t len; 179 BIGNUM *bignum; 180 181 (void) bufgap_getbin(bg, &len, sizeof(len)); 182 len = ntohl(len); 183 (void) bufgap_seek(bg, sizeof(len), BGFromHere, BGByte); 184 (void) bufgap_getbin(bg, buf, len); 185 bignum = BN_bin2bn((const unsigned char *)buf, (int)len, NULL); 186 if (__ops_get_debug_level(__FILE__)) { 187 show(header, buf, (int)len); 188 } 189 (void) bufgap_seek(bg, len, BGFromHere, BGByte); 190 return bignum; 191 } 192 193 static str_t pkatypes[] = { 194 { "ssh-rsa", 7, OPS_PKA_RSA }, 195 { "ssh-dsa", 7, OPS_PKA_DSA }, 196 { NULL, 0, 0 } 197 }; 198 199 /* look for a string in the given array */ 200 static int 201 findstr(str_t *array, const char *name) 202 { 203 str_t *sp; 204 205 for (sp = array ; sp->s ; sp++) { 206 if (strncmp(name, sp->s, sp->len) == 0) { 207 return sp->type; 208 } 209 } 210 return -1; 211 } 212 213 /* convert an ssh (host) pubkey to a pgp pubkey */ 214 int 215 __ops_ssh2pubkey(__ops_io_t *io, const char *f, __ops_key_t *key) 216 { 217 __ops_userid_t userid; 218 __ops_pubkey_t *pubkey; 219 struct stat st; 220 bufgap_t bg; 221 uint32_t len; 222 int64_t off; 223 char hostname[256]; 224 char *space; 225 char *buf; 226 char *bin; 227 int ok; 228 int cc; 229 230 (void) memset(&bg, 0x0, sizeof(bg)); 231 if (!bufgap_open(&bg, f)) { 232 (void) fprintf(stderr, "can't open '%s'\n", f); 233 return 0; 234 } 235 (void)stat(f, &st); 236 if ((buf = calloc(1, (size_t)st.st_size)) == NULL) { 237 (void) fprintf(stderr, "can't calloc %zu bytes for '%s'\n", (size_t)st.st_size, f); 238 bufgap_close(&bg); 239 return 0; 240 } 241 if ((bin = calloc(1, (size_t)st.st_size)) == NULL) { 242 (void) fprintf(stderr, "can't calloc %zu bytes for '%s'\n", (size_t)st.st_size, f); 243 (void) free(buf); 244 bufgap_close(&bg); 245 return 0; 246 } 247 248 /* move past ascii type of key */ 249 while (bufgap_peek(&bg, 0) != ' ') { 250 bufgap_seek(&bg, 1, BGFromHere, BGByte); 251 } 252 bufgap_seek(&bg, 1, BGFromHere, BGByte); 253 off = bufgap_tell(&bg, BGFromBOF, BGByte); 254 255 /* convert from base64 to binary */ 256 cc = bufgap_getbin(&bg, buf, (size_t)st.st_size); 257 if ((space = strchr(buf, ' ')) != NULL) { 258 cc = (int)(space - buf); 259 } 260 if (__ops_get_debug_level(__FILE__)) { 261 show(NULL, buf, cc); 262 } 263 cc = frombase64(bin, buf, (size_t)cc, 0); 264 if (__ops_get_debug_level(__FILE__)) { 265 show("decoded base64:", bin, cc); 266 } 267 bufgap_delete(&bg, (uint64_t)bufgap_tell(&bg, BGFromEOF, BGByte)); 268 bufgap_insert(&bg, bin, cc); 269 bufgap_seek(&bg, off, BGFromBOF, BGByte); 270 271 /* get the type of key */ 272 (void) bufgap_getbin(&bg, &len, sizeof(len)); 273 len = ntohl(len); 274 (void) bufgap_seek(&bg, sizeof(len), BGFromHere, BGByte); 275 (void) bufgap_getbin(&bg, buf, len); 276 (void) bufgap_seek(&bg, len, BGFromHere, BGByte); 277 278 (void) memset(key, 0x0, sizeof(*key)); 279 pubkey = &key->key.seckey.pubkey; 280 pubkey->version = OPS_V4; 281 pubkey->birthtime = st.st_mtime; 282 /* get key type */ 283 ok = 1; 284 switch (pubkey->alg = findstr(pkatypes, buf)) { 285 case OPS_PKA_RSA: 286 /* get the 'e' param of the key */ 287 pubkey->key.rsa.e = getbignum(&bg, buf, "RSA E"); 288 /* get the 'n' param of the key */ 289 pubkey->key.rsa.n = getbignum(&bg, buf, "RSA N"); 290 break; 291 case OPS_PKA_DSA: 292 /* get the 'p' param of the key */ 293 pubkey->key.dsa.p = getbignum(&bg, buf, "DSA P"); 294 /* get the 'q' param of the key */ 295 pubkey->key.dsa.q = getbignum(&bg, buf, "DSA Q"); 296 /* get the 'g' param of the key */ 297 pubkey->key.dsa.g = getbignum(&bg, buf, "DSA G"); 298 /* get the 'y' param of the key */ 299 pubkey->key.dsa.y = getbignum(&bg, buf, "DSA Y"); 300 break; 301 default: 302 (void) fprintf(stderr, "Unrecognised pubkey type %d for '%s'\n", 303 pubkey->alg, f); 304 ok = 0; 305 break; 306 } 307 308 /* check for stragglers */ 309 if (ok && bufgap_tell(&bg, BGFromEOF, BGByte) > 0) { 310 printf("%"PRIi64" bytes left\n", bufgap_tell(&bg, BGFromEOF, BGByte)); 311 printf("[%s]\n", bufgap_getstr(&bg)); 312 ok = 0; 313 } 314 if (ok) { 315 (void) memset(&userid, 0x0, sizeof(userid)); 316 (void) gethostname(hostname, sizeof(hostname)); 317 (void) asprintf((char **)(void *)&userid.userid, 318 "%s (%s) <%.*s>", 319 hostname, 320 f, 321 (int)strlen(space + 1) - 1, 322 space + 1); 323 __ops_keyid(key->key_id, sizeof(key->key_id), pubkey); 324 __ops_add_userid(key, &userid); 325 __ops_fingerprint(&key->fingerprint, pubkey); 326 free(userid.userid); 327 if (__ops_get_debug_level(__FILE__)) { 328 __ops_print_keydata(io, key, "pub", pubkey); 329 } 330 } 331 (void) free(bin); 332 (void) free(buf); 333 bufgap_close(&bg); 334 return ok; 335 } 336 337 /* convert an ssh (host) seckey to a pgp seckey */ 338 int 339 __ops_ssh2seckey(__ops_io_t *io, const char *f, __ops_key_t *key, __ops_pubkey_t *pubkey) 340 { 341 unsigned char sesskey[CAST_KEY_LENGTH]; 342 unsigned char hashed[OPS_SHA1_HASH_SIZE]; 343 __ops_crypt_t crypted; 344 __ops_hash_t hash; 345 unsigned int done = 0; 346 unsigned int i = 0; 347 348 /* XXX - check for rsa/dsa */ 349 if (!openssl_read_pem_seckey(f, key, "ssh-rsa")) { 350 return 0; 351 } 352 if (__ops_get_debug_level(__FILE__)) { 353 __ops_print_keydata(io, key, "sec", &key->key.seckey.pubkey); 354 } 355 /* let's add some sane defaults */ 356 (void) memcpy(&key->key.seckey.pubkey, pubkey, sizeof(*pubkey)); 357 key->key.seckey.s2k_usage = OPS_S2KU_ENCRYPTED_AND_HASHED; 358 key->key.seckey.alg = OPS_SA_CAST5; 359 key->key.seckey.s2k_specifier = OPS_S2KS_SALTED; 360 key->key.seckey.hash_alg = OPS_HASH_SHA1; 361 for (done = 0, i = 0; done < CAST_KEY_LENGTH; i++) { 362 unsigned char zero = 0; 363 unsigned j; 364 int needed; 365 int size; 366 367 needed = CAST_KEY_LENGTH - done; 368 size = MIN(needed, OPS_SHA1_HASH_SIZE); 369 370 __ops_hash_any(&hash, key->key.seckey.hash_alg); 371 if (!hash.init(&hash)) { 372 (void) fprintf(stderr, "write_seckey_body: bad alloc\n"); 373 return 0; 374 } 375 376 /* preload if iterating */ 377 for (j = 0; j < i; j++) { 378 /* 379 * Coverity shows a DEADCODE error on this 380 * line. This is expected since the hardcoded 381 * use of SHA1 and CAST5 means that it will 382 * not used. This will change however when 383 * other algorithms are supported. 384 */ 385 hash.add(&hash, &zero, 1); 386 } 387 388 if (key->key.seckey.s2k_specifier == OPS_S2KS_SALTED) { 389 hash.add(&hash, key->key.seckey.salt, OPS_SALT_SIZE); 390 } 391 hash.finish(&hash, hashed); 392 393 /* 394 * if more in hash than is needed by session key, use 395 * the leftmost octets 396 */ 397 (void) memcpy(&sesskey[i * OPS_SHA1_HASH_SIZE], 398 hashed, (unsigned)size); 399 done += (unsigned)size; 400 if (done > CAST_KEY_LENGTH) { 401 (void) fprintf(stderr, 402 "write_seckey_body: short add\n"); 403 return 0; 404 } 405 } 406 __ops_crypt_any(&crypted, key->key.seckey.alg); 407 crypted.set_iv(&crypted, key->key.seckey.iv); 408 crypted.set_crypt_key(&crypted, sesskey); 409 __ops_encrypt_init(&crypted); 410 key->key.seckey.pubkey.alg = OPS_PKA_RSA; 411 __ops_fingerprint(&key->fingerprint, pubkey); 412 __ops_keyid(key->key_id, sizeof(key->key_id), pubkey); 413 return 1; 414 } 415 416 /* read a key from the ssh file, and add it to a keyring */ 417 int 418 __ops_ssh2_readkeys(__ops_io_t *io, __ops_keyring_t *pubring, 419 __ops_keyring_t *secring, const char *pubfile, 420 const char *secfile) 421 { 422 __ops_key_t *pubkey; 423 __ops_key_t *seckey; 424 __ops_key_t key; 425 426 pubkey = NULL; 427 (void) memset(&key, 0x0, sizeof(key)); 428 if (pubfile) { 429 if (__ops_get_debug_level(__FILE__)) { 430 (void) fprintf(io->errs, "__ops_ssh2_readkeys: pubfile '%s'\n", pubfile); 431 } 432 __ops_ssh2pubkey(io, pubfile, &key); 433 EXPAND_ARRAY(pubring, key); 434 pubkey = &pubring->keys[pubring->keyc++]; 435 (void) memcpy(pubkey, &key, sizeof(key)); 436 pubkey->type = OPS_PTAG_CT_PUBLIC_KEY; 437 } 438 if (secfile) { 439 if (__ops_get_debug_level(__FILE__)) { 440 (void) fprintf(io->errs, "__ops_ssh2_readkeys: secfile '%s'\n", secfile); 441 } 442 if (pubkey == NULL) { 443 pubkey = &pubring->keys[0]; 444 } 445 (void) __ops_ssh2seckey(io, secfile, &key, &pubkey->key.pubkey); 446 EXPAND_ARRAY(secring, key); 447 seckey = &secring->keys[secring->keyc++]; 448 (void) memcpy(seckey, &key, sizeof(key)); 449 seckey->type = OPS_PTAG_CT_SECRET_KEY; 450 } 451 return 1; 452 } 453