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