release/src/router/dropbear/dropbearkey.c

   1 /*
   2  * Dropbear - a SSH2 server
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE. */
  24
  25 /* The format of the keyfiles is basically a raw dump of the buffer. Data types
  26  * are specified in the transport rfc 4253 - string is a 32-bit len then the
  27  * non-null-terminated string, mp_int is a 32-bit len then the bignum data.
  28  * The actual functions are buf_put_rsa_priv_key() and buf_put_dss_priv_key()
  29
  30  * RSA:
  31  * string       "ssh-rsa"
  32  * mp_int       e
  33  * mp_int       n
  34  * mp_int       d
  35  * mp_int       p (newer versions only)
  36  * mp_int       q (newer versions only)
  37  *
  38  * DSS:
  39  * string       "ssh-dss"
  40  * mp_int       p
  41  * mp_int       q
  42  * mp_int       g
  43  * mp_int       y
  44  * mp_int       x
  45  *
  46  */
  47 #include "includes.h"
  48 #include "signkey.h"
  49 #include "buffer.h"
  50 #include "dbutil.h"
  51
  52 #include "genrsa.h"
  53 #include "gendss.h"
  54
  55 static void printhelp(char * progname);
  56
  57 #define RSA_SIZE (1024/8) /* 1024 bit */
  58 #define DSS_SIZE (1024/8) /* 1024 bit */
  59
  60 static void buf_writefile(buffer * buf, const char * filename);
  61 static void printpubkey(sign_key * key, int keytype);
  62 static void justprintpub(const char* filename);
  63
  64 /* Print a help message */
  65 static void printhelp(char * progname) {
  66
  67         fprintf(stderr, "Usage: %s -t <type> -f <filename> [-s bits]\n"
  68                                         "-t type        Type of key to generate. One of:\n"
  69 #ifdef DROPBEAR_RSA
  70                                         "               rsa\n"
  71 #endif
  72 #ifdef DROPBEAR_DSS
  73                                         "               dss\n"
  74 #endif
  75                                         "-f filename    Use filename for the secret key\n"
  76                                         "-s bits        Key size in bits, should be a multiple of 8 (optional)\n"
  77                                         "           (DSS has a fixed size of 1024 bits)\n"
  78                                         "-y             Just print the publickey and fingerprint for the\n              private key in <filename>.\n"
  79 #ifdef DEBUG_TRACE
  80                                         "-v             verbose\n"
  81 #endif
  82                                         ,progname);
  83 }
  84
  85 #if defined(DBMULTI_dropbearkey) || !defined(DROPBEAR_MULTI)
  86 #if defined(DBMULTI_dropbearkey) && defined(DROPBEAR_MULTI)
  87 int dropbearkey_main(int argc, char ** argv) {
  88 #else
  89 int main(int argc, char ** argv) {
  90 #endif
  91
  92         int i;
  93         char ** next = 0;
  94         sign_key *key = NULL;
  95         buffer *buf = NULL;
  96         char * filename = NULL;
  97         int keytype = -1;
  98         char * typetext = NULL;
  99         char * sizetext = NULL;
 100         unsigned int bits;
 101         unsigned int keysize;
 102         int printpub = 0;
 103
 104         /* get the commandline options */
 105         for (i = 1; i < argc; i++) {
 106                 if (argv[i] == NULL) {
 107                         continue; /* Whack */
 108                 }
 109                 if (next) {
 110                         *next = argv[i];
 111                         next = NULL;
 112                         continue;
 113                 }
 114
 115                 if (argv[i][0] == '-') {
 116                         switch (argv[i][1]) {
 117                                 case 'f':
 118                                         next = &filename;
 119                                         break;
 120                                 case 't':
 121                                         next = &typetext;
 122                                         break;
 123                                 case 's':
 124                                         next = &sizetext;
 125                                         break;
 126                                 case 'y':
 127                                         printpub = 1;
 128                                         break;
 129                                 case 'h':
 130                                         printhelp(argv[0]);
 131                                         exit(EXIT_SUCCESS);
 132                                         break;
 133 #ifdef DEBUG_TRACE
 134                                 case 'v':
 135                                         debug_trace = 1;
 136                                         break;
 137 #endif
 138                                 default:
 139                                         fprintf(stderr, "Unknown argument %s\n", argv[i]);
 140                                         printhelp(argv[0]);
 141                                         exit(EXIT_FAILURE);
 142                                         break;
 143                         }
 144                 }
 145         }
 146
 147         if (!filename) {
 148                 fprintf(stderr, "Must specify a key filename\n");
 149                 printhelp(argv[0]);
 150                 exit(EXIT_FAILURE);
 151         }
 152
 153         if (printpub) {
 154                 justprintpub(filename);
 155                 /* Not reached */
 156         }
 157
 158         /* check/parse args */
 159         if (!typetext) {
 160                 fprintf(stderr, "Must specify key type\n");
 161                 printhelp(argv[0]);
 162                 exit(EXIT_FAILURE);
 163         }
 164
 165         if (strlen(typetext) == 3) {
 166 #ifdef DROPBEAR_RSA
 167                 if (strncmp(typetext, "rsa", 3) == 0) {
 168                         keytype = DROPBEAR_SIGNKEY_RSA;
 169                         TRACE(("type is rsa"))
 170                 }
 171 #endif
 172 #ifdef DROPBEAR_DSS
 173                 if (strncmp(typetext, "dss", 3) == 0) {
 174                         keytype = DROPBEAR_SIGNKEY_DSS;
 175                         TRACE(("type is dss"))
 176                 }
 177 #endif
 178         }
 179         if (keytype == -1) {
 180                 fprintf(stderr, "Unknown key type '%s'\n", typetext);
 181                 printhelp(argv[0]);
 182                 exit(EXIT_FAILURE);
 183         }
 184
 185         if (sizetext) {
 186                 if (sscanf(sizetext, "%u", &bits) != 1) {
 187                         fprintf(stderr, "Bits must be an integer\n");
 188                         exit(EXIT_FAILURE);
 189                 }
 190
 191                 if (keytype == DROPBEAR_SIGNKEY_DSS && bits != 1024) {
 192                         fprintf(stderr, "DSS keys have a fixed size of 1024 bits\n");
 193                         exit(EXIT_FAILURE);
 194                 } else if (bits < 512 || bits > 4096 || (bits % 8 != 0)) {
 195                         fprintf(stderr, "Bits must satisfy 512 <= bits <= 4096, and be a"
 196                                         " multiple of 8\n");
 197                         exit(EXIT_FAILURE);
 198                 }
 199
 200                 keysize = bits / 8;
 201         } else {
 202                 if (keytype == DROPBEAR_SIGNKEY_DSS) {
 203                         keysize = DSS_SIZE;
 204                 } else if (keytype == DROPBEAR_SIGNKEY_RSA) {
 205                         keysize = RSA_SIZE;
 206                 } else {
 207                         exit(EXIT_FAILURE); /* not reached */
 208                 }
 209         }
 210
 211
 212         fprintf(stderr, "Will output %d bit %s secret key to '%s'\n", keysize*8,
 213                         typetext, filename);
 214
 215         /* don't want the file readable by others */
 216         umask(077);
 217
 218         /* now we can generate the key */
 219         key = new_sign_key();
 220
 221         fprintf(stderr, "Generating key, this may take a while...\n");
 222         switch(keytype) {
 223 #ifdef DROPBEAR_RSA
 224                 case DROPBEAR_SIGNKEY_RSA:
 225                         key->rsakey = gen_rsa_priv_key(keysize); /* 128 bytes = 1024 bit */
 226                         break;
 227 #endif
 228 #ifdef DROPBEAR_DSS
 229                 case DROPBEAR_SIGNKEY_DSS:
 230                         key->dsskey = gen_dss_priv_key(keysize); /* 128 bytes = 1024 bit */
 231                         break;
 232 #endif
 233                 default:
 234                         fprintf(stderr, "Internal error, bad key type\n");
 235                         exit(EXIT_FAILURE);
 236         }
 237
 238         buf = buf_new(MAX_PRIVKEY_SIZE);
 239
 240         buf_put_priv_key(buf, key, keytype);
 241         buf_setpos(buf, 0);
 242         buf_writefile(buf, filename);
 243
 244         buf_burn(buf);
 245         buf_free(buf);
 246
 247         printpubkey(key, keytype);
 248
 249         sign_key_free(key);
 250
 251         return EXIT_SUCCESS;
 252 }
 253 #endif
 254
 255 static void justprintpub(const char* filename) {
 256
 257         buffer *buf = NULL;
 258         sign_key *key = NULL;
 259         int keytype;
 260         int ret;
 261         int err = DROPBEAR_FAILURE;
 262
 263         buf = buf_new(MAX_PRIVKEY_SIZE);
 264         ret = buf_readfile(buf, filename);
 265
 266         if (ret != DROPBEAR_SUCCESS) {
 267                 fprintf(stderr, "Failed reading '%s'\n", filename);
 268                 goto out;
 269         }
 270
 271         key = new_sign_key();
 272         keytype = DROPBEAR_SIGNKEY_ANY;
 273
 274         buf_setpos(buf, 0);
 275         ret = buf_get_priv_key(buf, key, &keytype);
 276         if (ret == DROPBEAR_FAILURE) {
 277                 fprintf(stderr, "Bad key in '%s'\n", filename);
 278                 goto out;
 279         }
 280
 281         printpubkey(key, keytype);
 282
 283         err = DROPBEAR_SUCCESS;
 284
 285 out:
 286         buf_burn(buf);
 287         buf_free(buf);
 288         buf = NULL;
 289         if (key) {
 290                 sign_key_free(key);
 291                 key = NULL;
 292         }
 293         exit(err);
 294 }
 295
 296 static void printpubkey(sign_key * key, int keytype) {
 297
 298         buffer * buf = NULL;
 299         unsigned char base64key[MAX_PUBKEY_SIZE*2];
 300         unsigned long base64len;
 301         int err;
 302         const char * typestring = NULL;
 303         char *fp = NULL;
 304         int len;
 305         struct passwd * pw = NULL;
 306         char * username = NULL;
 307         char hostname[100];
 308
 309         buf = buf_new(MAX_PUBKEY_SIZE);
 310         buf_put_pub_key(buf, key, keytype);
 311         buf_setpos(buf, 4);
 312
 313         len = buf->len - buf->pos;
 314
 315         base64len = sizeof(base64key);
 316         err = base64_encode(buf_getptr(buf, len), len, base64key, &base64len);
 317
 318         if (err != CRYPT_OK) {
 319                 fprintf(stderr, "base64 failed");
 320         }
 321
 322         typestring = signkey_name_from_type(keytype, &err);
 323
 324         fp = sign_key_fingerprint(buf_getptr(buf, len), len);
 325
 326         /* a user@host comment is informative */
 327         username = "";
 328         pw = getpwuid(getuid());
 329         if (pw) {
 330                 username = pw->pw_name;
 331         }
 332
 333         gethostname(hostname, sizeof(hostname));
 334         hostname[sizeof(hostname)-1] = '\0';
 335
 336         printf("Public key portion is:\n%s %s %s@%s\nFingerprint: %s\n",
 337                         typestring, base64key, username, hostname, fp);
 338
 339         m_free(fp);
 340         buf_free(buf);
 341 }
 342
 343 /* Write a buffer to a file specified, failing if the file exists */
 344 static void buf_writefile(buffer * buf, const char * filename) {
 345
 346         int fd;
 347         int len;
 348
 349         fd = open(filename, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
 350         if (fd < 0) {
 351                 fprintf(stderr, "Couldn't create new file %s\n", filename);
 352                 perror("Reason");
 353                 buf_burn(buf);
 354                 exit(EXIT_FAILURE);
 355         }
 356
 357         /* write the file now */
 358         while (buf->pos != buf->len) {
 359                 len = write(fd, buf_getptr(buf, buf->len - buf->pos),
 360                                 buf->len - buf->pos);
 361                 if (errno == EINTR) {
 362                         continue;
 363                 }
 364                 if (len <= 0) {
 365                         fprintf(stderr, "Failed writing file '%s'\n",filename);
 366                         perror("Reason");
 367                         exit(EXIT_FAILURE);
 368                 }
 369                 buf_incrpos(buf, len);
 370         }
 371
 372         close(fd);
 373 }