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                                         "Options are:\n"
  69                                         "-t type        Type of key to generate. One of:\n"
  70 #ifdef DROPBEAR_RSA
  71                                         "               rsa\n"
  72 #endif
  73 #ifdef DROPBEAR_DSS
  74                                         "               dss\n"
  75 #endif
  76                                         "-f filename    Use filename for the secret key\n"
  77                                         "-s bits        Key size in bits, should be a multiple of 8 (optional)\n"
  78                                         "           (DSS has a fixed size of 1024 bits)\n"
  79                                         "-y             Just print the publickey and fingerprint for the\n              private key in <filename>.\n"
  80 #ifdef DEBUG_TRACE
  81                                         "-v             verbose\n"
  82 #endif
  83                                         ,progname);
  84 }
  85
  86 #if defined(DBMULTI_dropbearkey) || !defined(DROPBEAR_MULTI)
  87 #if defined(DBMULTI_dropbearkey) && defined(DROPBEAR_MULTI)
  88 int dropbearkey_main(int argc, char ** argv) {
  89 #else
  90 int main(int argc, char ** argv) {
  91 #endif
  92
  93         int i;
  94         char ** next = 0;
  95         sign_key *key = NULL;
  96         buffer *buf = NULL;
  97         char * filename = NULL;
  98         int keytype = -1;
  99         char * typetext = NULL;
 100         char * sizetext = NULL;
 101         unsigned int bits;
 102         unsigned int keysize;
 103         int printpub = 0;
 104
 105         /* get the commandline options */
 106         for (i = 1; i < argc; i++) {
 107                 if (argv[i] == NULL) {
 108                         continue; /* Whack */
 109                 }
 110                 if (next) {
 111                         *next = argv[i];
 112                         next = NULL;
 113                         continue;
 114                 }
 115
 116                 if (argv[i][0] == '-') {
 117                         switch (argv[i][1]) {
 118                                 case 'f':
 119                                         next = &filename;
 120                                         break;
 121                                 case 't':
 122                                         next = &typetext;
 123                                         break;
 124                                 case 's':
 125                                         next = &sizetext;
 126                                         break;
 127                                 case 'y':
 128                                         printpub = 1;
 129                                         break;
 130                                 case 'h':
 131                                         printhelp(argv[0]);
 132                                         exit(EXIT_SUCCESS);
 133                                         break;
 134 #ifdef DEBUG_TRACE
 135                                 case 'v':
 136                                         debug_trace = 1;
 137                                         break;
 138 #endif
 139                                 default:
 140                                         fprintf(stderr, "Unknown argument %s\n", argv[i]);
 141                                         printhelp(argv[0]);
 142                                         exit(EXIT_FAILURE);
 143                                         break;
 144                         }
 145                 }
 146         }
 147
 148         if (!filename) {
 149                 fprintf(stderr, "Must specify a key filename\n");
 150                 printhelp(argv[0]);
 151                 exit(EXIT_FAILURE);
 152         }
 153
 154         if (printpub) {
 155                 justprintpub(filename);
 156                 /* Not reached */
 157         }
 158
 159         /* check/parse args */
 160         if (!typetext) {
 161                 fprintf(stderr, "Must specify key type\n");
 162                 printhelp(argv[0]);
 163                 exit(EXIT_FAILURE);
 164         }
 165
 166         if (strlen(typetext) == 3) {
 167 #ifdef DROPBEAR_RSA
 168                 if (strncmp(typetext, "rsa", 3) == 0) {
 169                         keytype = DROPBEAR_SIGNKEY_RSA;
 170                         TRACE(("type is rsa"))
 171                 }
 172 #endif
 173 #ifdef DROPBEAR_DSS
 174                 if (strncmp(typetext, "dss", 3) == 0) {
 175                         keytype = DROPBEAR_SIGNKEY_DSS;
 176                         TRACE(("type is dss"))
 177                 }
 178 #endif
 179         }
 180         if (keytype == -1) {
 181                 fprintf(stderr, "Unknown key type '%s'\n", typetext);
 182                 printhelp(argv[0]);
 183                 exit(EXIT_FAILURE);
 184         }
 185
 186         if (sizetext) {
 187                 if (sscanf(sizetext, "%u", &bits) != 1) {
 188                         fprintf(stderr, "Bits must be an integer\n");
 189                         exit(EXIT_FAILURE);
 190                 }
 191
 192                 if (keytype == DROPBEAR_SIGNKEY_DSS && bits != 1024) {
 193                         fprintf(stderr, "DSS keys have a fixed size of 1024 bits\n");
 194                         exit(EXIT_FAILURE);
 195                 } else if (bits < 512 || bits > 4096 || (bits % 8 != 0)) {
 196                         fprintf(stderr, "Bits must satisfy 512 <= bits <= 4096, and be a"
 197                                         " multiple of 8\n");
 198                         exit(EXIT_FAILURE);
 199                 }
 200
 201                 keysize = bits / 8;
 202         } else {
 203                 if (keytype == DROPBEAR_SIGNKEY_DSS) {
 204                         keysize = DSS_SIZE;
 205                 } else if (keytype == DROPBEAR_SIGNKEY_RSA) {
 206                         keysize = RSA_SIZE;
 207                 } else {
 208                         exit(EXIT_FAILURE); /* not reached */
 209                 }
 210         }
 211
 212
 213         fprintf(stderr, "Will output %d bit %s secret key to '%s'\n", keysize*8,
 214                         typetext, filename);
 215
 216         /* don't want the file readable by others */
 217         umask(077);
 218
 219         /* now we can generate the key */
 220         key = new_sign_key();
 221
 222         fprintf(stderr, "Generating key, this may take a while...\n");
 223         switch(keytype) {
 224 #ifdef DROPBEAR_RSA
 225                 case DROPBEAR_SIGNKEY_RSA:
 226                         key->rsakey = gen_rsa_priv_key(keysize); /* 128 bytes = 1024 bit */
 227                         break;
 228 #endif
 229 #ifdef DROPBEAR_DSS
 230                 case DROPBEAR_SIGNKEY_DSS:
 231                         key->dsskey = gen_dss_priv_key(keysize); /* 128 bytes = 1024 bit */
 232                         break;
 233 #endif
 234                 default:
 235                         fprintf(stderr, "Internal error, bad key type\n");
 236                         exit(EXIT_FAILURE);
 237         }
 238
 239         buf = buf_new(MAX_PRIVKEY_SIZE);
 240
 241         buf_put_priv_key(buf, key, keytype);
 242         buf_setpos(buf, 0);
 243         buf_writefile(buf, filename);
 244
 245         buf_burn(buf);
 246         buf_free(buf);
 247
 248         printpubkey(key, keytype);
 249
 250         sign_key_free(key);
 251
 252         return EXIT_SUCCESS;
 253 }
 254 #endif
 255
 256 static void justprintpub(const char* filename) {
 257
 258         buffer *buf = NULL;
 259         sign_key *key = NULL;
 260         int keytype;
 261         int ret;
 262         int err = DROPBEAR_FAILURE;
 263
 264         buf = buf_new(MAX_PRIVKEY_SIZE);
 265         ret = buf_readfile(buf, filename);
 266
 267         if (ret != DROPBEAR_SUCCESS) {
 268                 fprintf(stderr, "Failed reading '%s'\n", filename);
 269                 goto out;
 270         }
 271
 272         key = new_sign_key();
 273         keytype = DROPBEAR_SIGNKEY_ANY;
 274
 275         buf_setpos(buf, 0);
 276         ret = buf_get_priv_key(buf, key, &keytype);
 277         if (ret == DROPBEAR_FAILURE) {
 278                 fprintf(stderr, "Bad key in '%s'\n", filename);
 279                 goto out;
 280         }
 281
 282         printpubkey(key, keytype);
 283
 284         err = DROPBEAR_SUCCESS;
 285
 286 out:
 287         buf_burn(buf);
 288         buf_free(buf);
 289         buf = NULL;
 290         if (key) {
 291                 sign_key_free(key);
 292                 key = NULL;
 293         }
 294         exit(err);
 295 }
 296
 297 static void printpubkey(sign_key * key, int keytype) {
 298
 299         buffer * buf = NULL;
 300         unsigned char base64key[MAX_PUBKEY_SIZE*2];
 301         unsigned long base64len;
 302         int err;
 303         const char * typestring = NULL;
 304         char *fp = NULL;
 305         int len;
 306         struct passwd * pw = NULL;
 307         char * username = NULL;
 308         char hostname[100];
 309
 310         buf = buf_new(MAX_PUBKEY_SIZE);
 311         buf_put_pub_key(buf, key, keytype);
 312         buf_setpos(buf, 4);
 313
 314         len = buf->len - buf->pos;
 315
 316         base64len = sizeof(base64key);
 317         err = base64_encode(buf_getptr(buf, len), len, base64key, &base64len);
 318
 319         if (err != CRYPT_OK) {
 320                 fprintf(stderr, "base64 failed");
 321         }
 322
 323         typestring = signkey_name_from_type(keytype, &err);
 324
 325         fp = sign_key_fingerprint(buf_getptr(buf, len), len);
 326
 327         /* a user@host comment is informative */
 328         username = "";
 329         pw = getpwuid(getuid());
 330         if (pw) {
 331                 username = pw->pw_name;
 332         }
 333
 334         gethostname(hostname, sizeof(hostname));
 335         hostname[sizeof(hostname)-1] = '\0';
 336
 337         printf("Public key portion is:\n%s %s %s@%s\nFingerprint: %s\n",
 338                         typestring, base64key, username, hostname, fp);
 339
 340         m_free(fp);
 341         buf_free(buf);
 342 }
 343
 344 /* Write a buffer to a file specified, failing if the file exists */
 345 static void buf_writefile(buffer * buf, const char * filename) {
 346
 347         int fd;
 348         int len;
 349
 350         fd = open(filename, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
 351         if (fd < 0) {
 352                 fprintf(stderr, "Couldn't create new file %s\n", filename);
 353                 perror("Reason");
 354                 buf_burn(buf);
 355                 exit(EXIT_FAILURE);
 356         }
 357
 358         /* write the file now */
 359         while (buf->pos != buf->len) {
 360                 len = write(fd, buf_getptr(buf, buf->len - buf->pos),
 361                                 buf->len - buf->pos);
 362                 if (errno == EINTR) {
 363                         continue;
 364                 }
 365                 if (len <= 0) {
 366                         fprintf(stderr, "Failed writing file '%s'\n",filename);
 367                         perror("Reason");
 368                         exit(EXIT_FAILURE);
 369                 }
 370                 buf_incrpos(buf, len);
 371         }
 372
 373         close(fd);
 374 }