=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/cipher.c,v retrieving revision 1.26.2.2 retrieving revision 1.26.2.3 diff -u -r1.26.2.2 -r1.26.2.3 --- src/usr.bin/ssh/cipher.c 2000/09/01 18:23:18 1.26.2.2 +++ src/usr.bin/ssh/cipher.c 2000/11/08 21:30:34 1.26.2.3 @@ -1,25 +1,125 @@ /* - * - * cipher.c - * * Author: Tatu Ylonen - * * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * - * Created: Wed Apr 19 17:41:39 1995 ylo + * 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". * + * + * 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 1.26.2.2 2000/09/01 18:23:18 jason Exp $"); +RCSID("$OpenBSD: cipher.c,v 1.26.2.3 2000/11/08 21:30:34 jason Exp $"); #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: * @@ -35,160 +135,356 @@ * choosing the X block. */ void -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) +des3_ssh1_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); + 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_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT); + des_cbc_encrypt(src, dest, len, cc->u.des3.key1, &iv1, DES_ENCRYPT); memcpy(&iv1, dest + len - 8, 8); - des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT); + des_cbc_encrypt(dest, dest, len, cc->u.des3.key2, 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); + des_cbc_encrypt(dest, dest, len, cc->u.des3.key3, iv3, DES_ENCRYPT); memcpy(iv3, dest + len - 8, 8); } - void -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) +des3_ssh1_decrypt(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_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT); + des_cbc_encrypt(src, dest, len, cc->u.des3.key3, iv3, DES_DECRYPT); memcpy(iv3, src + len - 8, 8); - des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT); + des_cbc_encrypt(dest, dest, len, cc->u.des3.key2, iv2, DES_ENCRYPT); memcpy(iv2, dest + len - 8, 8); - des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT); + des_cbc_encrypt(dest, dest, len, cc->u.des3.key1, &iv1, DES_DECRYPT); /* memcpy(&iv1, iv2, 8); */ /* Note how iv1 == iv2 on entry and exit. */ } +/* Blowfish */ +void +blowfish_setkey(CipherContext *cc, const u_char *key, u_int keylen) +{ + BF_set_key(&cc->u.bf.key, keylen, (unsigned char *)key); +} +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 unsigned char *src, unsigned char *dst_, int n) +swap_bytes(const unsigned char *src, unsigned char *dst, int n) { - /* dst must be properly aligned. */ - u_int32_t *dst = (u_int32_t *) dst_; - union { - u_int32_t i; - char c[4]; - } t; + char c[4]; - /* 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; + /* Process 4 bytes every lap. */ + for (n = n / 4; n > 0; n--) { + c[3] = *src++; + c[2] = *src++; + c[1] = *src++; + c[0] = *src++; - 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]; } } -/* - * Names of all encryption algorithms. - * These must match the numbers defined in cipher.h. - */ -static char *cipher_names[] = +void +blowfish_ssh1_encrypt(CipherContext *cc, u_char *dest, const u_char *src, + u_int len) { - "none", - "idea", - "des", - "3des", - "tss", - "rc4", - "blowfish", - "reserved", - "blowfish-cbc", - "3des-cbc", - "arcfour", - "cast128-cbc" + 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); +} + +/* 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); +} + +/* CAST */ +void +cast_setkey(CipherContext *cc, const u_char *key, u_int keylen) +{ + CAST_set_key(&cc->u.cast.key, keylen, (unsigned char *) key); +} +void +cast_setiv(CipherContext *cc, const u_char *iv, u_int ivlen) +{ + if (iv == NULL) + fatal("no IV for %s.", cc->cipher->name); + memcpy(cc->u.cast.iv, (char *)iv, 8); +} +void +cast_cbc_encrypt(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_ENCRYPT); +} +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 */ + +#define RIJNDAEL_BLOCKSIZE 16 +void +rijndael_setkey(CipherContext *cc, const u_char *key, u_int keylen) +{ + rijndael_set_key(&cc->u.rijndael.enc, (u4byte *)key, 8*keylen, 1); + rijndael_set_key(&cc->u.rijndael.dec, (u4byte *)key, 8*keylen, 0); +} +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); +} + +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 } }; -/* - * Returns a bit mask indicating which ciphers are supported by this - * implementation. The bit mask has the corresponding bit set of each - * supported cipher. - */ +/*--*/ unsigned int -cipher_mask1() +cipher_mask_ssh1(int client) { unsigned int mask = 0; - mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ + mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ mask |= 1 << SSH_CIPHER_BLOWFISH; + if (client) { + mask |= 1 << SSH_CIPHER_DES; + } return mask; } -unsigned int -cipher_mask2() + +Cipher * +cipher_by_name(const char *name) { - 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; + Cipher *c; + for (c = ciphers; c->name != NULL; c++) + if (strcasecmp(c->name, name) == 0) + return c; + return NULL; } -unsigned int -cipher_mask() -{ - return cipher_mask1() | cipher_mask2(); -} -/* Returns the name of the cipher. */ - -const char * -cipher_name(int cipher) +Cipher * +cipher_by_number(int id) { - 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]; + Cipher *c; + for (c = ciphers; c->name != NULL; c++) + if (c->number == id) + return c; + return NULL; } -/* Returns 1 if the name of the ciphers are valid. */ - #define CIPHER_SEP "," int ciphers_valid(const char *names) { + Cipher *c; char *ciphers, *cp; 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'; + for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0'; (p = strsep(&cp, CIPHER_SEP))) { - i = cipher_number(p); - if (i == -1 || !(cipher_mask2() & (1 << i))) { + c = cipher_by_name(p); + if (c == NULL || c->number != SSH_CIPHER_SSH2) { + debug("bad cipher %s [%s]", p, names); xfree(ciphers); return 0; + } else { + debug3("cipher ok: %s [%s]", p, names); } } + debug3("ciphers ok: [%s]", names); xfree(ciphers); return 1; } @@ -201,264 +497,69 @@ int cipher_number(const char *name) { - int i; + Cipher *c; if (name == NULL) return -1; - 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; + c = cipher_by_name(name); + return (c==NULL) ? -1 : c->number; } -/* - * 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) +char * +cipher_name(int id) { - 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)); + Cipher *c = cipher_by_number(id); + return (c==NULL) ? "" : c->name; } -/* Selects the cipher to use and sets the key. */ - void -cipher_set_key(CipherContext *context, int cipher, const unsigned char *key, - int keylen) +cipher_init(CipherContext *cc, Cipher *cipher, + const u_char *key, u_int keylen, const u_char *iv, u_int 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)); + 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); } void -cipher_set_key_iv(CipherContext * context, int cipher, - const unsigned char *key, int keylen, - const unsigned char *iv, int ivlen) +cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int 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)); - } + if (len % cc->cipher->block_size) + fatal("cipher_encrypt: bad plaintext length %d", len); + cc->cipher->encrypt(cc, dest, src, len); } -/* Encrypts data using the cipher. */ - void -cipher_encrypt(CipherContext *context, unsigned char *dest, - const unsigned char *src, unsigned int len) +cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int 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)); - } + if (len % cc->cipher->block_size) + fatal("cipher_decrypt: bad ciphertext length %d", len); + cc->cipher->decrypt(cc, dest, src, len); } -/* Decrypts data using the cipher. */ +/* + * 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_decrypt(CipherContext *context, unsigned char *dest, - const unsigned char *src, unsigned int len) +cipher_set_key_string(CipherContext *cc, Cipher *cipher, + const char *passphrase) { - if ((len & 7) != 0) - fatal("cipher_decrypt: bad ciphertext length %d", len); + MD5_CTX md; + unsigned char digest[16]; - switch (context->type) { - case SSH_CIPHER_NONE: - memcpy(dest, src, len); - break; + MD5_Init(&md); + MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase)); + MD5_Final(digest, &md); - 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; + cipher_init(cc, cipher, digest, 16, NULL, 0); - 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)); - } + memset(digest, 0, sizeof(digest)); + memset(&md, 0, sizeof(md)); }