git.distorted.org.uk Git - u/mdw/putty/blob - mscrypto.c

   1 #define _WIN32_WINNT 0x0400
   2 #include <windows.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <wincrypt.h>
   6 #include "ssh.h"
   7
   8 void fatalbox(char *fmt, ...);
   9
  10 static HCRYPTKEY create_des_key(unsigned char *key);
  11
  12
  13 HCRYPTPROV hCryptProv;
  14 HCRYPTKEY hDESKey[2][3] = { {0, 0, 0}, {0, 0, 0} };     /* global for now */
  15
  16
  17 /* use Microsoft Enhanced Cryptographic Service Provider */
  18 #define CSP MS_ENHANCED_PROV
  19
  20
  21 static BYTE PrivateKeyWithExponentOfOne[] = {
  22     0x07, 0x02, 0x00, 0x00, 0x00, 0xA4, 0x00, 0x00,
  23     0x52, 0x53, 0x41, 0x32, 0x00, 0x02, 0x00, 0x00,
  24     0x01, 0x00, 0x00, 0x00, 0xAB, 0xEF, 0xFA, 0xC6,
  25     0x7D, 0xE8, 0xDE, 0xFB, 0x68, 0x38, 0x09, 0x92,
  26     0xD9, 0x42, 0x7E, 0x6B, 0x89, 0x9E, 0x21, 0xD7,
  27     0x52, 0x1C, 0x99, 0x3C, 0x17, 0x48, 0x4E, 0x3A,
  28     0x44, 0x02, 0xF2, 0xFA, 0x74, 0x57, 0xDA, 0xE4,
  29     0xD3, 0xC0, 0x35, 0x67, 0xFA, 0x6E, 0xDF, 0x78,
  30     0x4C, 0x75, 0x35, 0x1C, 0xA0, 0x74, 0x49, 0xE3,
  31     0x20, 0x13, 0x71, 0x35, 0x65, 0xDF, 0x12, 0x20,
  32     0xF5, 0xF5, 0xF5, 0xC1, 0xED, 0x5C, 0x91, 0x36,
  33     0x75, 0xB0, 0xA9, 0x9C, 0x04, 0xDB, 0x0C, 0x8C,
  34     0xBF, 0x99, 0x75, 0x13, 0x7E, 0x87, 0x80, 0x4B,
  35     0x71, 0x94, 0xB8, 0x00, 0xA0, 0x7D, 0xB7, 0x53,
  36     0xDD, 0x20, 0x63, 0xEE, 0xF7, 0x83, 0x41, 0xFE,
  37     0x16, 0xA7, 0x6E, 0xDF, 0x21, 0x7D, 0x76, 0xC0,
  38     0x85, 0xD5, 0x65, 0x7F, 0x00, 0x23, 0x57, 0x45,
  39     0x52, 0x02, 0x9D, 0xEA, 0x69, 0xAC, 0x1F, 0xFD,
  40     0x3F, 0x8C, 0x4A, 0xD0,
  41
  42     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  43     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  44     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  45     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  46
  47     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  48     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  49     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  50     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  51
  52     0x64, 0xD5, 0xAA, 0xB1,
  53     0xA6, 0x03, 0x18, 0x92, 0x03, 0xAA, 0x31, 0x2E,
  54     0x48, 0x4B, 0x65, 0x20, 0x99, 0xCD, 0xC6, 0x0C,
  55     0x15, 0x0C, 0xBF, 0x3E, 0xFF, 0x78, 0x95, 0x67,
  56     0xB1, 0x74, 0x5B, 0x60,
  57
  58     0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  59     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  60     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  61     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  62     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  63     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  64     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  65     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  66 };
  67
  68
  69
  70 /* ---------------------------------------------------------*
  71  * Utility functions                                        *
  72  * ---------------------------------------------------------*/
  73
  74
  75 int crypto_startup()
  76 {
  77     if (CryptAcquireContext(&hCryptProv, "Putty", CSP, PROV_RSA_FULL,
  78                             CRYPT_NEWKEYSET) == 0) {
  79         if (GetLastError() == NTE_EXISTS) {
  80             if (CryptAcquireContext(&hCryptProv, "Putty", CSP,
  81                                     PROV_RSA_FULL, 0) == 0) {
  82                 return FALSE;          /* failed to acquire context - probably
  83                                         * don't have high encryption installed! */
  84             }
  85         } else
  86             return FALSE;              /* failed to acquire context - probably
  87                                         * don't have high encryption installed! */
  88     }
  89     return TRUE;
  90 }
  91
  92
  93 void crypto_wrapup()
  94 {
  95     int i, j;
  96     for (i = 0; i < 2; i++) {
  97         for (j = 0; j < 3; j++) {
  98             if (hDESKey[i][j])
  99                 CryptDestroyKey(hDESKey[i][j]);
 100             hDESKey[i][j] = 0;
 101         }
 102     }
 103     if (hCryptProv)
 104         CryptReleaseContext(hCryptProv, 0);
 105     hCryptProv = 0;
 106 }
 107
 108
 109 /* ---------------------------------------------------------*
 110  * Random number functions                                  *
 111  * ---------------------------------------------------------*/
 112
 113 int random_byte(void)
 114 {
 115     unsigned char b;
 116     if (!CryptGenRandom(hCryptProv, 1, &b))
 117         fatalbox("random number generator failure!");
 118     return b;
 119 }
 120
 121 void random_add_noise(void *noise, int length)
 122 {
 123     /* do nothing */
 124 }
 125 void random_init(void)
 126 {
 127     /* do nothing */
 128 }
 129 void random_get_savedata(void **data, int *len)
 130 {
 131     /* do nothing */
 132 }
 133 void noise_get_heavy(void (*func) (void *, int))
 134 {
 135     /* do nothing */
 136 }
 137 void noise_get_light(void (*func) (void *, int))
 138 {
 139     /* do nothing */
 140 }
 141 void noise_ultralight(DWORD data)
 142 {
 143     /* do nothing */
 144 }
 145 void random_save_seed(void)
 146 {
 147     /* do nothing */
 148 }
 149
 150
 151 /* ---------------------------------------------------------*
 152  * MD5 hash functions                                       *
 153  * ---------------------------------------------------------*/
 154
 155
 156 void MD5Init(struct MD5Context *ctx)
 157 {
 158     if (!CryptCreateHash(hCryptProv, CALG_MD5, 0, 0, &ctx->hHash))
 159         fatalbox("Error during CryptBeginHash!\n");
 160 }
 161
 162
 163 void MD5Update(struct MD5Context *ctx,
 164                unsigned char const *buf, unsigned len)
 165 {
 166     if (CryptHashData(ctx->hHash, buf, len, 0) == 0)
 167         fatalbox("Error during CryptHashSessionKey!\n");
 168 }
 169
 170
 171 void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
 172 {
 173     DWORD cb = 16;
 174     if (CryptGetHashParam(ctx->hHash, HP_HASHVAL, digest, &cb, 0) == 0)
 175         fatalbox("Error during CryptGetHashParam!\n");
 176     if (ctx->hHash)
 177         CryptDestroyHash(ctx->hHash);
 178     ctx->hHash = 0;
 179 }
 180
 181
 182 /* ---------------------------------------------------------*
 183  * RSA public key functions                                 *
 184  * ---------------------------------------------------------*/
 185
 186 int makekey(unsigned char *data, struct RSAKey *result,
 187             unsigned char **keystr)
 188 {
 189
 190     unsigned char *p = data;
 191     int i;
 192     int w, b;
 193
 194     /* get size (bits) of modulus */
 195     result->bits = 0;
 196     for (i = 0; i < 4; i++)
 197         result->bits = (result->bits << 8) + *p++;
 198
 199     /* get size (bits) of public exponent */
 200     w = 0;
 201     for (i = 0; i < 2; i++)
 202         w = (w << 8) + *p++;
 203     b = (w + 7) / 8;                   /* bits -> bytes */
 204
 205     /* convert exponent to DWORD */
 206     result->exponent = 0;
 207     for (i = 0; i < b; i++)
 208         result->exponent = (result->exponent << 8) + *p++;
 209
 210     /* get size (bits) of modulus */
 211     w = 0;
 212     for (i = 0; i < 2; i++)
 213         w = (w << 8) + *p++;
 214     result->bytes = b = (w + 7) / 8;   /* bits -> bytes */
 215
 216     /* allocate buffer for modulus & copy it */
 217     result->modulus = malloc(b);
 218     memcpy(result->modulus, p, b);
 219
 220     /* update callers pointer */
 221     if (keystr)
 222         *keystr = p;                   /* point at key string, second time */
 223
 224     return (p - data) + b;
 225 }
 226
 227
 228 void rsaencrypt(unsigned char *data, int length, struct RSAKey *rsakey)
 229 {
 230
 231     int i;
 232     unsigned char *pKeybuf, *pKeyin;
 233     HCRYPTKEY hRsaKey;
 234     PUBLICKEYSTRUC *pBlob;
 235     RSAPUBKEY *pRPK;
 236     unsigned char *buf;
 237     DWORD dlen;
 238     DWORD bufsize;
 239
 240     /* allocate buffer for public key blob */
 241     if ((pBlob = malloc(sizeof(PUBLICKEYSTRUC) + sizeof(RSAPUBKEY) +
 242                         rsakey->bytes)) == NULL)
 243         fatalbox("Out of memory");
 244
 245     /* allocate buffer for message encryption block */
 246     bufsize = (length + rsakey->bytes) << 1;
 247     if ((buf = malloc(bufsize)) == NULL)
 248         fatalbox("Out of memory");
 249
 250     /* construct public key blob from host public key */
 251     pKeybuf = ((unsigned char *) pBlob) + sizeof(PUBLICKEYSTRUC) +
 252         sizeof(RSAPUBKEY);
 253     pKeyin = ((unsigned char *) rsakey->modulus);
 254     /* change big endian to little endian */
 255     for (i = 0; i < rsakey->bytes; i++)
 256         pKeybuf[i] = pKeyin[rsakey->bytes - i - 1];
 257     pBlob->bType = PUBLICKEYBLOB;
 258     pBlob->bVersion = 0x02;
 259     pBlob->reserved = 0;
 260     pBlob->aiKeyAlg = CALG_RSA_KEYX;
 261     pRPK =
 262         (RSAPUBKEY *) (((unsigned char *) pBlob) + sizeof(PUBLICKEYSTRUC));
 263     pRPK->magic = 0x31415352;          /* "RSA1" */
 264     pRPK->bitlen = rsakey->bits;
 265     pRPK->pubexp = rsakey->exponent;
 266
 267     /* import public key blob into key container */
 268     if (CryptImportKey(hCryptProv, (void *) pBlob,
 269                        sizeof(PUBLICKEYSTRUC) + sizeof(RSAPUBKEY) +
 270                        rsakey->bytes, 0, 0, &hRsaKey) == 0)
 271         fatalbox("Error importing RSA key!");
 272
 273     /* copy message into buffer */
 274     memcpy(buf, data, length);
 275     dlen = length;
 276
 277     /* using host public key, encrypt the message */
 278     if (CryptEncrypt(hRsaKey, 0, TRUE, 0, buf, &dlen, bufsize) == 0)
 279         fatalbox("Error encrypting using RSA key!");
 280
 281     /*
 282      * For some strange reason, Microsoft CryptEncrypt using public
 283      * key, returns the cyphertext in backwards (little endian)
 284      * order, so reverse it!
 285      */
 286     for (i = 0; i < (int) dlen; i++)
 287         data[i] = buf[dlen - i - 1];   /* make it big endian */
 288
 289     CryptDestroyKey(hRsaKey);
 290     free(buf);
 291     free(pBlob);
 292
 293 }
 294
 295
 296 int rsastr_len(struct RSAKey *key)
 297 {
 298     return 2 * (sizeof(DWORD) + key->bytes) + 10;
 299 }
 300
 301
 302 void rsastr_fmt(char *str, struct RSAKey *key)
 303 {
 304
 305     int len = 0, i;
 306
 307     sprintf(str + len, "%04x", key->exponent);
 308     len += strlen(str + len);
 309
 310     str[len++] = '/';
 311     for (i = 1; i < key->bytes; i++) {
 312         sprintf(str + len, "%02x", key->modulus[i]);
 313         len += strlen(str + len);
 314     }
 315     str[len] = '\0';
 316 }
 317
 318
 319
 320 /* ---------------------------------------------------------*
 321  * DES encryption / decryption functions                    *
 322  * ---------------------------------------------------------*/
 323
 324
 325 void des3_sesskey(unsigned char *key)
 326 {
 327     int i, j;
 328     for (i = 0; i < 2; i++) {
 329         for (j = 0; j < 3; j++) {
 330             hDESKey[i][j] = create_des_key(key + (j * 8));
 331         }
 332     }
 333 }
 334
 335
 336 void des3_encrypt_blk(unsigned char *blk, int len)
 337 {
 338
 339     DWORD dlen;
 340     dlen = len;
 341
 342     if (CryptEncrypt(hDESKey[0][0], 0, FALSE, 0, blk, &dlen, len + 8) == 0)
 343         fatalbox("Error encrypting block!\n");
 344     if (CryptDecrypt(hDESKey[0][1], 0, FALSE, 0, blk, &dlen) == 0)
 345         fatalbox("Error encrypting block!\n");
 346     if (CryptEncrypt(hDESKey[0][2], 0, FALSE, 0, blk, &dlen, len + 8) == 0)
 347         fatalbox("Error encrypting block!\n");
 348 }
 349
 350
 351 void des3_decrypt_blk(unsigned char *blk, int len)
 352 {
 353     DWORD dlen;
 354     dlen = len;
 355
 356     if (CryptDecrypt(hDESKey[1][2], 0, FALSE, 0, blk, &dlen) == 0)
 357         fatalbox("Error decrypting block!\n");
 358     if (CryptEncrypt(hDESKey[1][1], 0, FALSE, 0, blk, &dlen, len + 8) == 0)
 359         fatalbox("Error decrypting block!\n");
 360     if (CryptDecrypt(hDESKey[1][0], 0, FALSE, 0, blk, &dlen) == 0)
 361         fatalbox("Error decrypting block!\n");
 362 }
 363
 364
 365 struct ssh_cipher ssh_3des = {
 366     des3_sesskey,
 367     des3_encrypt_blk,
 368     des3_decrypt_blk
 369 };
 370
 371
 372 void des_sesskey(unsigned char *key)
 373 {
 374     int i;
 375     for (i = 0; i < 2; i++) {
 376         hDESKey[i][0] = create_des_key(key);
 377     }
 378 }
 379
 380
 381 void des_encrypt_blk(unsigned char *blk, int len)
 382 {
 383     DWORD dlen;
 384     dlen = len;
 385     if (CryptEncrypt(hDESKey[0][0], 0, FALSE, 0, blk, &dlen, len + 8) == 0)
 386         fatalbox("Error encrypting block!\n");
 387 }
 388
 389
 390 void des_decrypt_blk(unsigned char *blk, int len)
 391 {
 392     DWORD dlen;
 393     dlen = len;
 394     if (CryptDecrypt(hDESKey[1][0], 0, FALSE, 0, blk, &dlen) == 0)
 395         fatalbox("Error decrypting block!\n");
 396 }
 397
 398 struct ssh_cipher ssh_des = {
 399     des_sesskey,
 400     des_encrypt_blk,
 401     des_decrypt_blk
 402 };
 403
 404
 405 static HCRYPTKEY create_des_key(unsigned char *key)
 406 {
 407
 408     HCRYPTKEY hSessionKey, hPrivateKey;
 409     DWORD dlen = 8;
 410     BLOBHEADER *pbh;
 411     char buf[sizeof(BLOBHEADER) + sizeof(ALG_ID) + 256];
 412
 413     /*
 414      * Need special private key to encrypt session key so we can
 415      * import session key, since only encrypted session keys can be
 416      * imported
 417      */
 418     if (CryptImportKey(hCryptProv, PrivateKeyWithExponentOfOne,
 419                        sizeof(PrivateKeyWithExponentOfOne),
 420                        0, 0, &hPrivateKey) == 0)
 421         return 0;
 422
 423     /* now encrypt session key using special private key */
 424     memcpy(buf + sizeof(BLOBHEADER) + sizeof(ALG_ID), key, 8);
 425     if (CryptEncrypt(hPrivateKey, 0, TRUE, 0,
 426                      buf + sizeof(BLOBHEADER) + sizeof(ALG_ID),
 427                      &dlen, 256) == 0)
 428         return 0;
 429
 430     /* build session key blob */
 431     pbh = (BLOBHEADER *) buf;
 432     pbh->bType = SIMPLEBLOB;
 433     pbh->bVersion = 0x02;
 434     pbh->reserved = 0;
 435     pbh->aiKeyAlg = CALG_DES;
 436     *((ALG_ID *) (buf + sizeof(BLOBHEADER))) = CALG_RSA_KEYX;
 437
 438     /* import session key into key container */
 439     if (CryptImportKey(hCryptProv, buf,
 440                        dlen + sizeof(BLOBHEADER) + sizeof(ALG_ID),
 441                        hPrivateKey, 0, &hSessionKey) == 0)
 442         return 0;
 443
 444     if (hPrivateKey)
 445         CryptDestroyKey(hPrivateKey);
 446
 447     return hSessionKey;
 448
 449 }