Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 2 | * |
| 3 | * cipher.c |
| 4 | * |
| 5 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 6 | * |
| 7 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 8 | * All rights reserved |
| 9 | * |
| 10 | * Created: Wed Apr 19 17:41:39 1995 ylo |
| 11 | * |
| 12 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 13 | |
| 14 | #include "includes.h" |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 15 | RCSID("$Id: cipher.c,v 1.16 2000/04/06 02:32:39 damien Exp $"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 16 | |
| 17 | #include "ssh.h" |
| 18 | #include "cipher.h" |
Damien Miller | 1fa154b | 2000-01-23 10:32:03 +1100 | [diff] [blame] | 19 | #include "config.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 20 | |
Damien Miller | 7f6ea02 | 1999-10-28 13:25:17 +1000 | [diff] [blame] | 21 | #ifdef HAVE_OPENSSL |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 22 | #include <openssl/md5.h> |
Damien Miller | 7f6ea02 | 1999-10-28 13:25:17 +1000 | [diff] [blame] | 23 | #endif |
| 24 | #ifdef HAVE_SSL |
| 25 | #include <ssl/md5.h> |
| 26 | #endif |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 27 | |
| 28 | /* |
| 29 | * What kind of tripple DES are these 2 routines? |
| 30 | * |
| 31 | * Why is there a redundant initialization vector? |
| 32 | * |
| 33 | * If only iv3 was used, then, this would till effect have been |
| 34 | * outer-cbc. However, there is also a private iv1 == iv2 which |
| 35 | * perhaps makes differential analysis easier. On the other hand, the |
| 36 | * private iv1 probably makes the CRC-32 attack ineffective. This is a |
| 37 | * result of that there is no longer any known iv1 to use when |
| 38 | * choosing the X block. |
| 39 | */ |
| 40 | void |
| 41 | SSH_3CBC_ENCRYPT(des_key_schedule ks1, |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 42 | des_key_schedule ks2, des_cblock * iv2, |
| 43 | des_key_schedule ks3, des_cblock * iv3, |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 44 | unsigned char *dest, unsigned char *src, |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 45 | unsigned int len) |
| 46 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 47 | des_cblock iv1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 48 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 49 | memcpy(&iv1, iv2, 8); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 50 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 51 | des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT); |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 52 | memcpy(&iv1, dest + len - 8, 8); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 53 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 54 | des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT); |
| 55 | memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 56 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 57 | des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT); |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 58 | memcpy(iv3, dest + len - 8, 8); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 59 | } |
| 60 | |
| 61 | void |
| 62 | SSH_3CBC_DECRYPT(des_key_schedule ks1, |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 63 | des_key_schedule ks2, des_cblock * iv2, |
| 64 | des_key_schedule ks3, des_cblock * iv3, |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 65 | unsigned char *dest, unsigned char *src, |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 66 | unsigned int len) |
| 67 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 68 | des_cblock iv1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 69 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 70 | memcpy(&iv1, iv2, 8); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 71 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 72 | des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT); |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 73 | memcpy(iv3, src + len - 8, 8); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 74 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 75 | des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT); |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 76 | memcpy(iv2, dest + len - 8, 8); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 77 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 78 | des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT); |
| 79 | /* memcpy(&iv1, iv2, 8); */ |
| 80 | /* Note how iv1 == iv2 on entry and exit. */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 81 | } |
| 82 | |
| 83 | /* |
| 84 | * SSH uses a variation on Blowfish, all bytes must be swapped before |
| 85 | * and after encryption/decryption. Thus the swap_bytes stuff (yuk). |
| 86 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 87 | static void |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 88 | swap_bytes(const unsigned char *src, unsigned char *dst_, int n) |
| 89 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 90 | /* dst must be properly aligned. */ |
| 91 | u_int32_t *dst = (u_int32_t *) dst_; |
| 92 | union { |
| 93 | u_int32_t i; |
| 94 | char c[4]; |
| 95 | } t; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 96 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 97 | /* Process 8 bytes every lap. */ |
| 98 | for (n = n / 8; n > 0; n--) { |
| 99 | t.c[3] = *src++; |
| 100 | t.c[2] = *src++; |
| 101 | t.c[1] = *src++; |
| 102 | t.c[0] = *src++; |
| 103 | *dst++ = t.i; |
| 104 | |
| 105 | t.c[3] = *src++; |
| 106 | t.c[2] = *src++; |
| 107 | t.c[1] = *src++; |
| 108 | t.c[0] = *src++; |
| 109 | *dst++ = t.i; |
| 110 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 111 | } |
| 112 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 113 | /* |
| 114 | * Names of all encryption algorithms. |
| 115 | * These must match the numbers defined in cipher.h. |
| 116 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 117 | static char *cipher_names[] = |
| 118 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 119 | "none", |
| 120 | "idea", |
| 121 | "des", |
| 122 | "3des", |
| 123 | "tss", |
| 124 | "rc4", |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 125 | "blowfish", |
| 126 | "reserved", |
| 127 | "blowfish-cbc", |
| 128 | "3des-cbc", |
| 129 | "arcfour", |
| 130 | "cast128-cbc" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 131 | }; |
| 132 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 133 | /* |
| 134 | * Returns a bit mask indicating which ciphers are supported by this |
| 135 | * implementation. The bit mask has the corresponding bit set of each |
| 136 | * supported cipher. |
| 137 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 138 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 139 | unsigned int |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 140 | cipher_mask1() |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 141 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 142 | unsigned int mask = 0; |
| 143 | mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ |
| 144 | mask |= 1 << SSH_CIPHER_BLOWFISH; |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 145 | return mask; |
| 146 | } |
| 147 | unsigned int |
| 148 | cipher_mask2() |
| 149 | { |
| 150 | unsigned int mask = 0; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 151 | mask |= 1 << SSH_CIPHER_BLOWFISH_CBC; |
| 152 | mask |= 1 << SSH_CIPHER_3DES_CBC; |
| 153 | mask |= 1 << SSH_CIPHER_ARCFOUR; |
| 154 | mask |= 1 << SSH_CIPHER_CAST128_CBC; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 155 | return mask; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 156 | } |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 157 | unsigned int |
| 158 | cipher_mask() |
| 159 | { |
| 160 | return cipher_mask1() | cipher_mask2(); |
| 161 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 162 | |
| 163 | /* Returns the name of the cipher. */ |
| 164 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 165 | const char * |
| 166 | cipher_name(int cipher) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 167 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 168 | if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) || |
| 169 | cipher_names[cipher] == NULL) |
| 170 | fatal("cipher_name: bad cipher number: %d", cipher); |
| 171 | return cipher_names[cipher]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 172 | } |
| 173 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 174 | /* |
| 175 | * Parses the name of the cipher. Returns the number of the corresponding |
| 176 | * cipher, or -1 on error. |
| 177 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 178 | |
| 179 | int |
| 180 | cipher_number(const char *name) |
| 181 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 182 | int i; |
| 183 | for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++) |
| 184 | if (strcmp(cipher_names[i], name) == 0 && |
| 185 | (cipher_mask() & (1 << i))) |
| 186 | return i; |
| 187 | return -1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 188 | } |
| 189 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 190 | /* |
| 191 | * Selects the cipher, and keys if by computing the MD5 checksum of the |
| 192 | * passphrase and using the resulting 16 bytes as the key. |
| 193 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 194 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 195 | void |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 196 | cipher_set_key_string(CipherContext *context, int cipher, const char *passphrase) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 197 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 198 | MD5_CTX md; |
| 199 | unsigned char digest[16]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 200 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 201 | MD5_Init(&md); |
| 202 | MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase)); |
| 203 | MD5_Final(digest, &md); |
| 204 | |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 205 | cipher_set_key(context, cipher, digest, 16); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 206 | |
| 207 | memset(digest, 0, sizeof(digest)); |
| 208 | memset(&md, 0, sizeof(md)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 209 | } |
| 210 | |
| 211 | /* Selects the cipher to use and sets the key. */ |
| 212 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 213 | void |
Damien Miller | 1383bd8 | 2000-04-06 12:32:37 +1000 | [diff] [blame^] | 214 | cipher_set_key(CipherContext *context, int cipher, const unsigned char *key, |
| 215 | int keylen) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 216 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 217 | unsigned char padded[32]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 218 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 219 | /* Set cipher type. */ |
| 220 | context->type = cipher; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 221 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 222 | /* Get 32 bytes of key data. Pad if necessary. (So that code |
| 223 | below does not need to worry about key size). */ |
| 224 | memset(padded, 0, sizeof(padded)); |
| 225 | memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 226 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 227 | /* Initialize the initialization vector. */ |
| 228 | switch (cipher) { |
| 229 | case SSH_CIPHER_NONE: |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 230 | /* |
| 231 | * Has to stay for authfile saving of private key with no |
| 232 | * passphrase |
| 233 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 234 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 235 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 236 | case SSH_CIPHER_3DES: |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 237 | /* |
| 238 | * Note: the least significant bit of each byte of key is |
| 239 | * parity, and must be ignored by the implementation. 16 |
| 240 | * bytes of key are used (first and last keys are the same). |
| 241 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 242 | if (keylen < 16) |
| 243 | error("Key length %d is insufficient for 3DES.", keylen); |
| 244 | des_set_key((void *) padded, context->u.des3.key1); |
| 245 | des_set_key((void *) (padded + 8), context->u.des3.key2); |
| 246 | if (keylen <= 16) |
| 247 | des_set_key((void *) padded, context->u.des3.key3); |
| 248 | else |
| 249 | des_set_key((void *) (padded + 16), context->u.des3.key3); |
| 250 | memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2)); |
| 251 | memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3)); |
| 252 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 253 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 254 | case SSH_CIPHER_BLOWFISH: |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 255 | if (keylen < 16) |
| 256 | error("Key length %d is insufficient for blowfish.", keylen); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 257 | BF_set_key(&context->u.bf.key, keylen, padded); |
| 258 | memset(context->u.bf.iv, 0, 8); |
| 259 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 260 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 261 | case SSH_CIPHER_3DES_CBC: |
| 262 | case SSH_CIPHER_BLOWFISH_CBC: |
| 263 | case SSH_CIPHER_ARCFOUR: |
| 264 | case SSH_CIPHER_CAST128_CBC: |
| 265 | fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher)); |
| 266 | break; |
| 267 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 268 | default: |
| 269 | fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher)); |
| 270 | } |
| 271 | memset(padded, 0, sizeof(padded)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 272 | } |
| 273 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 274 | |
| 275 | void |
| 276 | cipher_set_key_iv(CipherContext * context, int cipher, |
| 277 | const unsigned char *key, int keylen, |
| 278 | const unsigned char *iv, int ivlen) |
| 279 | { |
| 280 | /* Set cipher type. */ |
| 281 | context->type = cipher; |
| 282 | |
| 283 | /* Initialize the initialization vector. */ |
| 284 | switch (cipher) { |
| 285 | case SSH_CIPHER_NONE: |
| 286 | break; |
| 287 | |
| 288 | case SSH_CIPHER_3DES: |
| 289 | case SSH_CIPHER_BLOWFISH: |
| 290 | fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher)); |
| 291 | break; |
| 292 | |
| 293 | case SSH_CIPHER_3DES_CBC: |
| 294 | if (keylen < 24) |
| 295 | error("Key length %d is insufficient for 3des-cbc.", keylen); |
| 296 | des_set_key((void *) key, context->u.des3.key1); |
| 297 | des_set_key((void *) (key+8), context->u.des3.key2); |
| 298 | des_set_key((void *) (key+16), context->u.des3.key3); |
| 299 | if (ivlen < 8) |
| 300 | error("IV length %d is insufficient for 3des-cbc.", ivlen); |
| 301 | memcpy(context->u.des3.iv3, (char *)iv, 8); |
| 302 | break; |
| 303 | |
| 304 | case SSH_CIPHER_BLOWFISH_CBC: |
| 305 | if (keylen < 16) |
| 306 | error("Key length %d is insufficient for blowfish.", keylen); |
| 307 | if (ivlen < 8) |
| 308 | error("IV length %d is insufficient for blowfish.", ivlen); |
| 309 | BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key); |
| 310 | memcpy(context->u.bf.iv, (char *)iv, 8); |
| 311 | break; |
| 312 | |
| 313 | case SSH_CIPHER_ARCFOUR: |
| 314 | if (keylen < 16) |
| 315 | error("Key length %d is insufficient for arcfour.", keylen); |
| 316 | RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key); |
| 317 | break; |
| 318 | |
| 319 | case SSH_CIPHER_CAST128_CBC: |
| 320 | if (keylen < 16) |
| 321 | error("Key length %d is insufficient for cast128.", keylen); |
| 322 | if (ivlen < 8) |
| 323 | error("IV length %d is insufficient for cast128.", ivlen); |
| 324 | CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key); |
| 325 | memcpy(context->u.cast.iv, (char *)iv, 8); |
| 326 | break; |
| 327 | |
| 328 | default: |
| 329 | fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher)); |
| 330 | } |
| 331 | } |
| 332 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 333 | /* Encrypts data using the cipher. */ |
| 334 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 335 | void |
| 336 | cipher_encrypt(CipherContext *context, unsigned char *dest, |
| 337 | const unsigned char *src, unsigned int len) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 338 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 339 | if ((len & 7) != 0) |
| 340 | fatal("cipher_encrypt: bad plaintext length %d", len); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 341 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 342 | switch (context->type) { |
| 343 | case SSH_CIPHER_NONE: |
| 344 | memcpy(dest, src, len); |
| 345 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 346 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 347 | case SSH_CIPHER_3DES: |
| 348 | SSH_3CBC_ENCRYPT(context->u.des3.key1, |
| 349 | context->u.des3.key2, &context->u.des3.iv2, |
| 350 | context->u.des3.key3, &context->u.des3.iv3, |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 351 | dest, (unsigned char *) src, len); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 352 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 353 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 354 | case SSH_CIPHER_BLOWFISH: |
| 355 | swap_bytes(src, dest, len); |
| 356 | BF_cbc_encrypt(dest, dest, len, |
| 357 | &context->u.bf.key, context->u.bf.iv, |
| 358 | BF_ENCRYPT); |
| 359 | swap_bytes(dest, dest, len); |
| 360 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 361 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 362 | case SSH_CIPHER_BLOWFISH_CBC: |
| 363 | BF_cbc_encrypt((void *)src, dest, len, |
| 364 | &context->u.bf.key, context->u.bf.iv, |
| 365 | BF_ENCRYPT); |
| 366 | break; |
| 367 | |
| 368 | case SSH_CIPHER_3DES_CBC: |
| 369 | des_ede3_cbc_encrypt(src, dest, len, |
| 370 | context->u.des3.key1, context->u.des3.key2, |
| 371 | context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT); |
| 372 | break; |
| 373 | |
| 374 | case SSH_CIPHER_ARCFOUR: |
| 375 | RC4(&context->u.rc4, len, (unsigned char *)src, dest); |
| 376 | break; |
| 377 | |
| 378 | case SSH_CIPHER_CAST128_CBC: |
| 379 | CAST_cbc_encrypt(src, dest, len, |
| 380 | &context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT); |
| 381 | break; |
| 382 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 383 | default: |
| 384 | fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type)); |
| 385 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 386 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 387 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 388 | /* Decrypts data using the cipher. */ |
| 389 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 390 | void |
| 391 | cipher_decrypt(CipherContext *context, unsigned char *dest, |
| 392 | const unsigned char *src, unsigned int len) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 393 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 394 | if ((len & 7) != 0) |
| 395 | fatal("cipher_decrypt: bad ciphertext length %d", len); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 396 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 397 | switch (context->type) { |
| 398 | case SSH_CIPHER_NONE: |
| 399 | memcpy(dest, src, len); |
| 400 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 401 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 402 | case SSH_CIPHER_3DES: |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 403 | SSH_3CBC_DECRYPT(context->u.des3.key1, |
| 404 | context->u.des3.key2, &context->u.des3.iv2, |
| 405 | context->u.des3.key3, &context->u.des3.iv3, |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 406 | dest, (unsigned char *) src, len); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 407 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 408 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 409 | case SSH_CIPHER_BLOWFISH: |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 410 | swap_bytes(src, dest, len); |
| 411 | BF_cbc_encrypt((void *) dest, dest, len, |
| 412 | &context->u.bf.key, context->u.bf.iv, |
| 413 | BF_DECRYPT); |
| 414 | swap_bytes(dest, dest, len); |
| 415 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 416 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 417 | case SSH_CIPHER_BLOWFISH_CBC: |
| 418 | BF_cbc_encrypt((void *) src, dest, len, |
| 419 | &context->u.bf.key, context->u.bf.iv, |
| 420 | BF_DECRYPT); |
| 421 | break; |
| 422 | |
| 423 | case SSH_CIPHER_3DES_CBC: |
| 424 | des_ede3_cbc_encrypt(src, dest, len, |
| 425 | context->u.des3.key1, context->u.des3.key2, |
| 426 | context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT); |
| 427 | break; |
| 428 | |
| 429 | case SSH_CIPHER_ARCFOUR: |
| 430 | RC4(&context->u.rc4, len, (unsigned char *)src, dest); |
| 431 | break; |
| 432 | |
| 433 | case SSH_CIPHER_CAST128_CBC: |
| 434 | CAST_cbc_encrypt(src, dest, len, |
| 435 | &context->u.cast.key, context->u.cast.iv, CAST_DECRYPT); |
| 436 | break; |
| 437 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 438 | default: |
| 439 | fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type)); |
| 440 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 441 | } |