diff options
Diffstat (limited to 'crypto/openssh/cipher.c')
| -rw-r--r-- | crypto/openssh/cipher.c | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/crypto/openssh/cipher.c b/crypto/openssh/cipher.c new file mode 100644 index 0000000..bb91d7e --- /dev/null +++ b/crypto/openssh/cipher.c @@ -0,0 +1,566 @@ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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". + * + * + * 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 1.37 2000/10/23 19:31:54 markus Exp $"); +RCSID("$FreeBSD$"); + +#include "ssh.h" +#include "xmalloc.h" + +#include <openssl/md5.h> + + +/* 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: + * + * What kind of triple DES are these 2 routines? + * + * Why is there a redundant initialization vector? + * + * If only iv3 was used, then, this would till effect have been + * outer-cbc. However, there is also a private iv1 == iv2 which + * perhaps makes differential analysis easier. On the other hand, the + * private iv1 probably makes the CRC-32 attack ineffective. This is a + * result of that there is no longer any known iv1 to use when + * choosing the X block. + */ +void +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, cc->u.des3.key1, &iv1, DES_ENCRYPT); + memcpy(&iv1, dest + len - 8, 8); + + 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, cc->u.des3.key3, 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) +{ + 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, cc->u.des3.key3, iv3, DES_DECRYPT); + memcpy(iv3, src + len - 8, 8); + + 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, 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) +{ + char c[4]; + + /* Process 4 bytes every lap. */ + for (n = n / 4; n > 0; n--) { + c[3] = *src++; + c[2] = *src++; + c[1] = *src++; + c[0] = *src++; + + *dst++ = c[0]; + *dst++ = c[1]; + *dst++ = c[2]; + *dst++ = c[3]; + } +} + +void +blowfish_ssh1_encrypt(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_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 } +}; + +/*--*/ + +unsigned int +cipher_mask_ssh1(int client) +{ + unsigned 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 *p; + + 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); + xfree(ciphers); + return 0; + } else { + debug3("cipher ok: %s [%s]", p, names); + } + } + debug3("ciphers ok: [%s]", names); + xfree(ciphers); + return 1; +} + +/* + * Parses the name of the cipher. Returns the number of the corresponding + * cipher, or -1 on error. + */ + +int +cipher_number(const char *name) +{ + Cipher *c; + if (name == NULL) + return -1; + c = cipher_by_name(name); + return (c==NULL) ? -1 : c->number; +} + +char * +cipher_name(int id) +{ + Cipher *c = cipher_by_number(id); + return (c==NULL) ? "<unknown>" : c->name; +} + +void +cipher_init(CipherContext *cc, Cipher *cipher, + const u_char *key, u_int keylen, const u_char *iv, u_int ivlen) +{ + 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_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) +{ + if (len % cc->cipher->block_size) + fatal("cipher_encrypt: bad plaintext length %d", len); + cc->cipher->encrypt(cc, dest, src, len); +} + +void +cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len) +{ + if (len % cc->cipher->block_size) + fatal("cipher_decrypt: bad ciphertext length %d", len); + cc->cipher->decrypt(cc, dest, src, len); +} + +/* + * 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 *cc, Cipher *cipher, + const char *passphrase) +{ + MD5_CTX md; + unsigned char digest[16]; + + MD5_Init(&md); + MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase)); + MD5_Final(digest, &md); + + cipher_init(cc, cipher, digest, 16, NULL, 0); + + memset(digest, 0, sizeof(digest)); + memset(&md, 0, sizeof(md)); +} |
