=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/cipher.c,v retrieving revision 1.26.2.5 retrieving revision 1.27 diff -u -r1.26.2.5 -r1.27 --- src/usr.bin/ssh/cipher.c 2001/03/21 18:52:40 1.26.2.5 +++ src/usr.bin/ssh/cipher.c 2000/05/22 18:42:00 1.27 @@ -1,126 +1,25 @@ /* + * + * cipher.c + * * Author: Tatu Ylonen + * * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * - * As far as I am concerned, the code I have written for this software - * can be used freely for any purpose. Any derived versions of this - * software must be clearly marked as such, and if the derived work is - * incompatible with the protocol description in the RFC file, it must be - * called by a name other than "ssh" or "Secure Shell". + * Created: Wed Apr 19 17:41:39 1995 ylo * - * - * Copyright (c) 1999 Niels Provos. All rights reserved. - * Copyright (c) 1999,2000 Markus Friedl. All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES - * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. - * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, - * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF - * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" -RCSID("$OpenBSD: cipher.c,v 1.26.2.5 2001/03/21 18:52:40 jason Exp $"); +RCSID("$Id: cipher.c,v 1.27 2000/05/22 18:42:00 markus Exp $"); -#include "xmalloc.h" -#include "log.h" +#include "ssh.h" #include "cipher.h" +#include "xmalloc.h" #include - -/* no encryption */ -void -none_setkey(CipherContext *cc, const u_char *key, u_int keylen) -{ -} -void -none_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) -{ -} -void -none_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - memcpy(dest, src, len); -} - -/* DES */ -void -des_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen) -{ - static int dowarn = 1; - if (dowarn) { - error("Warning: use of DES is strongly discouraged " - "due to cryptographic weaknesses"); - dowarn = 0; - } - des_set_key((void *)key, cc->u.des.key); -} -void -des_ssh1_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) -{ - memset(cc->u.des.iv, 0, sizeof(cc->u.des.iv)); -} -void -des_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv, - DES_ENCRYPT); -} -void -des_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - des_ncbc_encrypt(src, dest, len, cc->u.des.key, &cc->u.des.iv, - DES_DECRYPT); -} - -/* 3DES */ -void -des3_setkey(CipherContext *cc, const u_char *key, u_int keylen) -{ - des_set_key((void *) key, cc->u.des3.key1); - des_set_key((void *) (key+8), cc->u.des3.key2); - des_set_key((void *) (key+16), cc->u.des3.key3); -} -void -des3_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) -{ - memset(cc->u.des3.iv2, 0, sizeof(cc->u.des3.iv2)); - memset(cc->u.des3.iv3, 0, sizeof(cc->u.des3.iv3)); - if (iv == NULL) - return; - memcpy(cc->u.des3.iv3, (char *)iv, 8); -} -void -des3_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - des_ede3_cbc_encrypt(src, dest, len, - cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3, - &cc->u.des3.iv3, DES_ENCRYPT); -} -void -des3_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - des_ede3_cbc_encrypt(src, dest, len, - cc->u.des3.key1, cc->u.des3.key2, cc->u.des3.key3, - &cc->u.des3.iv3, DES_DECRYPT); -} - /* * This is used by SSH1: * @@ -136,345 +35,159 @@ * choosing the X block. */ void -des3_ssh1_setkey(CipherContext *cc, const u_char *key, u_int keylen) +SSH_3CBC_ENCRYPT(des_key_schedule ks1, + des_key_schedule ks2, des_cblock * iv2, + des_key_schedule ks3, des_cblock * iv3, + unsigned char *dest, unsigned char *src, + unsigned int len) { - des_set_key((void *) key, cc->u.des3.key1); - des_set_key((void *) (key+8), cc->u.des3.key2); - if (keylen <= 16) - des_set_key((void *) key, cc->u.des3.key3); - else - des_set_key((void *) (key+16), cc->u.des3.key3); -} -void -des3_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) -{ des_cblock iv1; - des_cblock *iv2 = &cc->u.des3.iv2; - des_cblock *iv3 = &cc->u.des3.iv3; memcpy(&iv1, iv2, 8); - des_ncbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT); - des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_DECRYPT); - des_ncbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT); + des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT); + memcpy(&iv1, dest + len - 8, 8); + + des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT); + memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */ + + des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT); + memcpy(iv3, dest + len - 8, 8); } + void -des3_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) +SSH_3CBC_DECRYPT(des_key_schedule ks1, + des_key_schedule ks2, des_cblock * iv2, + des_key_schedule ks3, des_cblock * iv3, + unsigned char *dest, unsigned char *src, + unsigned int len) { des_cblock iv1; - des_cblock *iv2 = &cc->u.des3.iv2; - des_cblock *iv3 = &cc->u.des3.iv3; memcpy(&iv1, iv2, 8); - des_ncbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT); - des_ncbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT); - des_ncbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT); -} + des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT); + memcpy(iv3, src + len - 8, 8); -/* Blowfish */ -void -blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen) -{ - BF_set_key(&cc->u.bf.key, keylen, (u_char *)key); + des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT); + memcpy(iv2, dest + len - 8, 8); + + des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT); + /* memcpy(&iv1, iv2, 8); */ + /* Note how iv1 == iv2 on entry and exit. */ } -void -blowfish_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) -{ - if (iv == NULL) - memset(cc->u.bf.iv, 0, 8); - else - memcpy(cc->u.bf.iv, (char *)iv, 8); -} -void -blowfish_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) -{ - BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv, - BF_ENCRYPT); -} -void -blowfish_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) -{ - BF_cbc_encrypt((void *)src, dest, len, &cc->u.bf.key, cc->u.bf.iv, - BF_DECRYPT); -} /* * SSH1 uses a variation on Blowfish, all bytes must be swapped before * and after encryption/decryption. Thus the swap_bytes stuff (yuk). */ static void -swap_bytes(const u_char *src, u_char *dst, int n) +swap_bytes(const unsigned char *src, unsigned char *dst_, int n) { - char c[4]; + /* dst must be properly aligned. */ + u_int32_t *dst = (u_int32_t *) dst_; + union { + u_int32_t i; + char c[4]; + } t; - /* Process 4 bytes every lap. */ - for (n = n / 4; n > 0; n--) { - c[3] = *src++; - c[2] = *src++; - c[1] = *src++; - c[0] = *src++; + /* Process 8 bytes every lap. */ + for (n = n / 8; n > 0; n--) { + t.c[3] = *src++; + t.c[2] = *src++; + t.c[1] = *src++; + t.c[0] = *src++; + *dst++ = t.i; - *dst++ = c[0]; - *dst++ = c[1]; - *dst++ = c[2]; - *dst++ = c[3]; + t.c[3] = *src++; + t.c[2] = *src++; + t.c[1] = *src++; + t.c[0] = *src++; + *dst++ = t.i; } } -void -blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) +/* + * Names of all encryption algorithms. + * These must match the numbers defined in cipher.h. + */ +static char *cipher_names[] = { - swap_bytes(src, dest, len); - BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv, - BF_ENCRYPT); - swap_bytes(dest, dest, len); -} -void -blowfish_ssh1_decrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) -{ - swap_bytes(src, dest, len); - BF_cbc_encrypt((void *)dest, dest, len, &cc->u.bf.key, cc->u.bf.iv, - BF_DECRYPT); - swap_bytes(dest, dest, len); -} + "none", + "idea", + "des", + "3des", + "tss", + "rc4", + "blowfish", + "reserved", + "blowfish-cbc", + "3des-cbc", + "arcfour", + "cast128-cbc" +}; -/* alleged rc4 */ -void -arcfour_setkey(CipherContext *cc, const u_char *key, u_int keylen) -{ - RC4_set_key(&cc->u.rc4, keylen, (u_char *)key); -} -void -arcfour_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - RC4(&cc->u.rc4, len, (u_char *)src, dest); -} +/* + * Returns a bit mask indicating which ciphers are supported by this + * implementation. The bit mask has the corresponding bit set of each + * supported cipher. + */ -/* CAST */ -void -cast_setkey(CipherContext *cc, const u_char *key, u_int keylen) +unsigned int +cipher_mask1() { - CAST_set_key(&cc->u.cast.key, keylen, (u_char *) key); + unsigned int mask = 0; + mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ + mask |= 1 << SSH_CIPHER_BLOWFISH; + return mask; } -void -cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) +unsigned int +cipher_mask2() { - if (iv == NULL) - fatal("no IV for %s.", cc->cipher->name); - memcpy(cc->u.cast.iv, (char *)iv, 8); + unsigned int mask = 0; + mask |= 1 << SSH_CIPHER_BLOWFISH_CBC; + mask |= 1 << SSH_CIPHER_3DES_CBC; + mask |= 1 << SSH_CIPHER_ARCFOUR; + mask |= 1 << SSH_CIPHER_CAST128_CBC; + return mask; } -void -cast_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) +unsigned int +cipher_mask() { - CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv, - CAST_ENCRYPT); + return cipher_mask1() | cipher_mask2(); } -void -cast_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) -{ - CAST_cbc_encrypt(src, dest, len, &cc->u.cast.key, cc->u.cast.iv, - CAST_DECRYPT); -} -/* RIJNDAEL */ +/* Returns the name of the cipher. */ -#define RIJNDAEL_BLOCKSIZE 16 -void -rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen) +const char * +cipher_name(int cipher) { - rijndael_set_key(&cc->u.rijndael.enc, (u4byte *)key, 8*keylen, 1); - rijndael_set_key(&cc->u.rijndael.dec, (u4byte *)key, 8*keylen, 0); + if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) || + cipher_names[cipher] == NULL) + fatal("cipher_name: bad cipher name: %d", cipher); + return cipher_names[cipher]; } -void -rijndael_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) -{ - if (iv == NULL) - fatal("no IV for %s.", cc->cipher->name); - memcpy((u_char *)cc->u.rijndael.iv, iv, RIJNDAEL_BLOCKSIZE); -} -void -rijndael_cbc_encrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) -{ - rijndael_ctx *ctx = &cc->u.rijndael.enc; - u4byte *iv = cc->u.rijndael.iv; - u4byte in[4]; - u4byte *cprev, *cnow, *plain; - int i, blocks = len / RIJNDAEL_BLOCKSIZE; - if (len == 0) - return; - if (len % RIJNDAEL_BLOCKSIZE) - fatal("rijndael_cbc_encrypt: bad len %d", len); - cnow = (u4byte*) dest; - plain = (u4byte*) src; - cprev = iv; - for(i = 0; i < blocks; i++, plain+=4, cnow+=4) { - in[0] = plain[0] ^ cprev[0]; - in[1] = plain[1] ^ cprev[1]; - in[2] = plain[2] ^ cprev[2]; - in[3] = plain[3] ^ cprev[3]; - rijndael_encrypt(ctx, in, cnow); - cprev = cnow; - } - memcpy(iv, cprev, RIJNDAEL_BLOCKSIZE); -} -void -rijndael_cbc_decrypt(CipherContext *cc, u_char *dest, const u_char *src, - u_int len) -{ - rijndael_ctx *ctx = &cc->u.rijndael.dec; - u4byte *iv = cc->u.rijndael.iv; - u4byte ivsaved[4]; - u4byte *cnow = (u4byte*) (src+len-RIJNDAEL_BLOCKSIZE); - u4byte *plain = (u4byte*) (dest+len-RIJNDAEL_BLOCKSIZE); - u4byte *ivp; - int i, blocks = len / RIJNDAEL_BLOCKSIZE; - if (len == 0) - return; - if (len % RIJNDAEL_BLOCKSIZE) - fatal("rijndael_cbc_decrypt: bad len %d", len); - memcpy(ivsaved, cnow, RIJNDAEL_BLOCKSIZE); - for(i = blocks; i > 0; i--, cnow-=4, plain-=4) { - rijndael_decrypt(ctx, cnow, plain); - ivp = (i == 1) ? iv : cnow-4; - plain[0] ^= ivp[0]; - plain[1] ^= ivp[1]; - plain[2] ^= ivp[2]; - plain[3] ^= ivp[3]; - } - memcpy(iv, ivsaved, RIJNDAEL_BLOCKSIZE); -} +/* Returns 1 if the name of the ciphers are valid. */ -Cipher ciphers[] = { - { "none", - SSH_CIPHER_NONE, 8, 0, - none_setkey, none_setiv, - none_crypt, none_crypt }, - { "des", - SSH_CIPHER_DES, 8, 8, - des_ssh1_setkey, des_ssh1_setiv, - des_ssh1_encrypt, des_ssh1_decrypt }, - { "3des", - SSH_CIPHER_3DES, 8, 16, - des3_ssh1_setkey, des3_setiv, - des3_ssh1_encrypt, des3_ssh1_decrypt }, - { "blowfish", - SSH_CIPHER_BLOWFISH, 8, 16, - blowfish_setkey, blowfish_setiv, - blowfish_ssh1_encrypt, blowfish_ssh1_decrypt }, - - { "3des-cbc", - SSH_CIPHER_SSH2, 8, 24, - des3_setkey, des3_setiv, - des3_cbc_encrypt, des3_cbc_decrypt }, - { "blowfish-cbc", - SSH_CIPHER_SSH2, 8, 16, - blowfish_setkey, blowfish_setiv, - blowfish_cbc_encrypt, blowfish_cbc_decrypt }, - { "cast128-cbc", - SSH_CIPHER_SSH2, 8, 16, - cast_setkey, cast_setiv, - cast_cbc_encrypt, cast_cbc_decrypt }, - { "arcfour", - SSH_CIPHER_SSH2, 8, 16, - arcfour_setkey, none_setiv, - arcfour_crypt, arcfour_crypt }, - { "aes128-cbc", - SSH_CIPHER_SSH2, 16, 16, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { "aes192-cbc", - SSH_CIPHER_SSH2, 16, 24, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { "aes256-cbc", - SSH_CIPHER_SSH2, 16, 32, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { "rijndael128-cbc", - SSH_CIPHER_SSH2, 16, 16, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { "rijndael192-cbc", - SSH_CIPHER_SSH2, 16, 24, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { "rijndael256-cbc", - SSH_CIPHER_SSH2, 16, 32, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { "rijndael-cbc@lysator.liu.se", - SSH_CIPHER_SSH2, 16, 32, - rijndael_setkey, rijndael_setiv, - rijndael_cbc_encrypt, rijndael_cbc_decrypt }, - { NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL, NULL, NULL, NULL } -}; - -/*--*/ - -u_int -cipher_mask_ssh1(int client) -{ - u_int mask = 0; - mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ - mask |= 1 << SSH_CIPHER_BLOWFISH; - if (client) { - mask |= 1 << SSH_CIPHER_DES; - } - return mask; -} - -Cipher * -cipher_by_name(const char *name) -{ - Cipher *c; - for (c = ciphers; c->name != NULL; c++) - if (strcasecmp(c->name, name) == 0) - return c; - return NULL; -} - -Cipher * -cipher_by_number(int id) -{ - Cipher *c; - for (c = ciphers; c->name != NULL; c++) - if (c->number == id) - return c; - return NULL; -} - #define CIPHER_SEP "," int ciphers_valid(const char *names) { - Cipher *c; - char *ciphers, *cp; + char *ciphers; char *p; + int i; if (names == NULL || strcmp(names, "") == 0) return 0; - ciphers = cp = xstrdup(names); - for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0'; - (p = strsep(&cp, CIPHER_SEP))) { - c = cipher_by_name(p); - if (c == NULL || c->number != SSH_CIPHER_SSH2) { - debug("bad cipher %s [%s]", p, names); + ciphers = xstrdup(names); + for ((p = strtok(ciphers, CIPHER_SEP)); p; (p = strtok(NULL, CIPHER_SEP))) { + i = cipher_number(p); + if (i == -1 || !(cipher_mask2() & (1 << i))) { xfree(ciphers); return 0; - } else { - debug3("cipher ok: %s [%s]", p, names); } } - debug3("ciphers ok: [%s]", names); xfree(ciphers); return 1; } @@ -487,69 +200,264 @@ int cipher_number(const char *name) { - Cipher *c; + int i; if (name == NULL) return -1; - c = cipher_by_name(name); - return (c==NULL) ? -1 : c->number; + for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++) + if (strcmp(cipher_names[i], name) == 0 && + (cipher_mask() & (1 << i))) + return i; + return -1; } -char * -cipher_name(int id) +/* + * Selects the cipher, and keys if by computing the MD5 checksum of the + * passphrase and using the resulting 16 bytes as the key. + */ + +void +cipher_set_key_string(CipherContext *context, int cipher, const char *passphrase) { - Cipher *c = cipher_by_number(id); - return (c==NULL) ? "" : c->name; + MD5_CTX md; + unsigned char digest[16]; + + MD5_Init(&md); + MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase)); + MD5_Final(digest, &md); + + cipher_set_key(context, cipher, digest, 16); + + memset(digest, 0, sizeof(digest)); + memset(&md, 0, sizeof(md)); } +/* Selects the cipher to use and sets the key. */ + void -cipher_init(CipherContext *cc, Cipher *cipher, - const u_char *key, u_int keylen, const u_char *iv, u_int ivlen) +cipher_set_key(CipherContext *context, int cipher, const unsigned char *key, + int keylen) { - if (keylen < cipher->key_len) - fatal("cipher_init: key length %d is insufficient for %s.", - keylen, cipher->name); - if (iv != NULL && ivlen < cipher->block_size) - fatal("cipher_init: iv length %d is insufficient for %s.", - ivlen, cipher->name); - cc->cipher = cipher; - cipher->setkey(cc, key, keylen); - cipher->setiv(cc, iv, ivlen); + unsigned char padded[32]; + + /* Set cipher type. */ + context->type = cipher; + + /* Get 32 bytes of key data. Pad if necessary. (So that code + below does not need to worry about key size). */ + memset(padded, 0, sizeof(padded)); + memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded)); + + /* Initialize the initialization vector. */ + switch (cipher) { + case SSH_CIPHER_NONE: + /* + * Has to stay for authfile saving of private key with no + * passphrase + */ + break; + + case SSH_CIPHER_3DES: + /* + * Note: the least significant bit of each byte of key is + * parity, and must be ignored by the implementation. 16 + * bytes of key are used (first and last keys are the same). + */ + if (keylen < 16) + error("Key length %d is insufficient for 3DES.", keylen); + des_set_key((void *) padded, context->u.des3.key1); + des_set_key((void *) (padded + 8), context->u.des3.key2); + if (keylen <= 16) + des_set_key((void *) padded, context->u.des3.key3); + else + des_set_key((void *) (padded + 16), context->u.des3.key3); + memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2)); + memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3)); + break; + + case SSH_CIPHER_BLOWFISH: + if (keylen < 16) + error("Key length %d is insufficient for blowfish.", keylen); + BF_set_key(&context->u.bf.key, keylen, padded); + memset(context->u.bf.iv, 0, 8); + break; + + case SSH_CIPHER_3DES_CBC: + case SSH_CIPHER_BLOWFISH_CBC: + case SSH_CIPHER_ARCFOUR: + case SSH_CIPHER_CAST128_CBC: + fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher)); + break; + + default: + fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher)); + } + memset(padded, 0, sizeof(padded)); } void -cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) +cipher_set_key_iv(CipherContext * context, int cipher, + const unsigned char *key, int keylen, + const unsigned char *iv, int ivlen) { - if (len % cc->cipher->block_size) - fatal("cipher_encrypt: bad plaintext length %d", len); - cc->cipher->encrypt(cc, dest, src, len); + /* Set cipher type. */ + context->type = cipher; + + /* Initialize the initialization vector. */ + switch (cipher) { + case SSH_CIPHER_NONE: + break; + + case SSH_CIPHER_3DES: + case SSH_CIPHER_BLOWFISH: + fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher)); + break; + + case SSH_CIPHER_3DES_CBC: + if (keylen < 24) + error("Key length %d is insufficient for 3des-cbc.", keylen); + des_set_key((void *) key, context->u.des3.key1); + des_set_key((void *) (key+8), context->u.des3.key2); + des_set_key((void *) (key+16), context->u.des3.key3); + if (ivlen < 8) + error("IV length %d is insufficient for 3des-cbc.", ivlen); + memcpy(context->u.des3.iv3, (char *)iv, 8); + break; + + case SSH_CIPHER_BLOWFISH_CBC: + if (keylen < 16) + error("Key length %d is insufficient for blowfish.", keylen); + if (ivlen < 8) + error("IV length %d is insufficient for blowfish.", ivlen); + BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key); + memcpy(context->u.bf.iv, (char *)iv, 8); + break; + + case SSH_CIPHER_ARCFOUR: + if (keylen < 16) + error("Key length %d is insufficient for arcfour.", keylen); + RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key); + break; + + case SSH_CIPHER_CAST128_CBC: + if (keylen < 16) + error("Key length %d is insufficient for cast128.", keylen); + if (ivlen < 8) + error("IV length %d is insufficient for cast128.", ivlen); + CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key); + memcpy(context->u.cast.iv, (char *)iv, 8); + break; + + default: + fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher)); + } } +/* Encrypts data using the cipher. */ + void -cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) +cipher_encrypt(CipherContext *context, unsigned char *dest, + const unsigned char *src, unsigned int len) { - if (len % cc->cipher->block_size) - fatal("cipher_decrypt: bad ciphertext length %d", len); - cc->cipher->decrypt(cc, dest, src, len); + if ((len & 7) != 0) + fatal("cipher_encrypt: bad plaintext length %d", len); + + switch (context->type) { + case SSH_CIPHER_NONE: + memcpy(dest, src, len); + break; + + case SSH_CIPHER_3DES: + SSH_3CBC_ENCRYPT(context->u.des3.key1, + context->u.des3.key2, &context->u.des3.iv2, + context->u.des3.key3, &context->u.des3.iv3, + dest, (unsigned char *) src, len); + break; + + case SSH_CIPHER_BLOWFISH: + swap_bytes(src, dest, len); + BF_cbc_encrypt(dest, dest, len, + &context->u.bf.key, context->u.bf.iv, + BF_ENCRYPT); + swap_bytes(dest, dest, len); + break; + + case SSH_CIPHER_BLOWFISH_CBC: + BF_cbc_encrypt((void *)src, dest, len, + &context->u.bf.key, context->u.bf.iv, + BF_ENCRYPT); + break; + + case SSH_CIPHER_3DES_CBC: + des_ede3_cbc_encrypt(src, dest, len, + context->u.des3.key1, context->u.des3.key2, + context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT); + break; + + case SSH_CIPHER_ARCFOUR: + RC4(&context->u.rc4, len, (unsigned char *)src, dest); + break; + + case SSH_CIPHER_CAST128_CBC: + CAST_cbc_encrypt(src, dest, len, + &context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT); + break; + + default: + fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type)); + } } -/* - * Selects the cipher, and keys if by computing the MD5 checksum of the - * passphrase and using the resulting 16 bytes as the key. - */ +/* Decrypts data using the cipher. */ void -cipher_set_key_string(CipherContext *cc, Cipher *cipher, - const char *passphrase) +cipher_decrypt(CipherContext *context, unsigned char *dest, + const unsigned char *src, unsigned int len) { - MD5_CTX md; - u_char digest[16]; + if ((len & 7) != 0) + fatal("cipher_decrypt: bad ciphertext length %d", len); - MD5_Init(&md); - MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase)); - MD5_Final(digest, &md); + switch (context->type) { + case SSH_CIPHER_NONE: + memcpy(dest, src, len); + break; - cipher_init(cc, cipher, digest, 16, NULL, 0); + case SSH_CIPHER_3DES: + SSH_3CBC_DECRYPT(context->u.des3.key1, + context->u.des3.key2, &context->u.des3.iv2, + context->u.des3.key3, &context->u.des3.iv3, + dest, (unsigned char *) src, len); + break; - memset(digest, 0, sizeof(digest)); - memset(&md, 0, sizeof(md)); + case SSH_CIPHER_BLOWFISH: + swap_bytes(src, dest, len); + BF_cbc_encrypt((void *) dest, dest, len, + &context->u.bf.key, context->u.bf.iv, + BF_DECRYPT); + swap_bytes(dest, dest, len); + break; + + case SSH_CIPHER_BLOWFISH_CBC: + BF_cbc_encrypt((void *) src, dest, len, + &context->u.bf.key, context->u.bf.iv, + BF_DECRYPT); + break; + + case SSH_CIPHER_3DES_CBC: + des_ede3_cbc_encrypt(src, dest, len, + context->u.des3.key1, context->u.des3.key2, + context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT); + break; + + case SSH_CIPHER_ARCFOUR: + RC4(&context->u.rc4, len, (unsigned char *)src, dest); + break; + + case SSH_CIPHER_CAST128_CBC: + CAST_cbc_encrypt(src, dest, len, + &context->u.cast.key, context->u.cast.iv, CAST_DECRYPT); + break; + + default: + fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type)); + } }