| /* |
| * 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 1.75 2005/06/09 13:43:49 dtucker Exp $"); |
| |
| #include "xmalloc.h" |
| #include "log.h" |
| #include "cipher.h" |
| |
| #include <openssl/md5.h> |
| |
| extern const EVP_CIPHER *evp_ssh1_bf(void); |
| extern const EVP_CIPHER *evp_ssh1_3des(void); |
| extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); |
| extern const EVP_CIPHER *evp_aes_128_ctr(void); |
| extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int); |
| |
| struct Cipher { |
| char *name; |
| int number; /* for ssh1 only */ |
| u_int block_size; |
| u_int key_len; |
| u_int discard_len; |
| const EVP_CIPHER *(*evptype)(void); |
| } ciphers[] = { |
| { "none", SSH_CIPHER_NONE, 8, 0, 0, EVP_enc_null }, |
| { "des", SSH_CIPHER_DES, 8, 8, 0, EVP_des_cbc }, |
| { "3des", SSH_CIPHER_3DES, 8, 16, 0, evp_ssh1_3des }, |
| { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, evp_ssh1_bf }, |
| |
| { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, EVP_des_ede3_cbc }, |
| { "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_bf_cbc }, |
| { "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_cast5_cbc }, |
| { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, EVP_rc4 }, |
| { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 1536, EVP_rc4 }, |
| { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 1536, EVP_rc4 }, |
| { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, EVP_aes_128_cbc }, |
| { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, EVP_aes_192_cbc }, |
| { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc }, |
| { "rijndael-cbc@lysator.liu.se", |
| SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc }, |
| { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, evp_aes_128_ctr }, |
| { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, evp_aes_128_ctr }, |
| { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, evp_aes_128_ctr }, |
| #ifdef USE_CIPHER_ACSS |
| { "acss@openssh.org", SSH_CIPHER_SSH2, 16, 5, 0, EVP_acss }, |
| #endif |
| { NULL, SSH_CIPHER_INVALID, 0, 0, 0, NULL } |
| }; |
| |
| /*--*/ |
| |
| u_int |
| cipher_blocksize(const Cipher *c) |
| { |
| return (c->block_size); |
| } |
| |
| u_int |
| cipher_keylen(const Cipher *c) |
| { |
| return (c->key_len); |
| } |
| |
| u_int |
| cipher_get_number(const Cipher *c) |
| { |
| return (c->number); |
| } |
| |
| 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 (strcmp(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 *cipher_list, *cp; |
| char *p; |
| |
| if (names == NULL || strcmp(names, "") == 0) |
| return 0; |
| cipher_list = 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(cipher_list); |
| return 0; |
| } else { |
| debug3("cipher ok: %s [%s]", p, names); |
| } |
| } |
| debug3("ciphers ok: [%s]", names); |
| xfree(cipher_list); |
| 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; |
| for (c = ciphers; c->name != NULL; c++) |
| if (strcasecmp(c->name, name) == 0) |
| return c->number; |
| return -1; |
| } |
| |
| 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, |
| int do_encrypt) |
| { |
| static int dowarn = 1; |
| #ifdef SSH_OLD_EVP |
| EVP_CIPHER *type; |
| #else |
| const EVP_CIPHER *type; |
| int klen; |
| #endif |
| u_char *junk, *discard; |
| |
| if (cipher->number == SSH_CIPHER_DES) { |
| if (dowarn) { |
| error("Warning: use of DES is strongly discouraged " |
| "due to cryptographic weaknesses"); |
| dowarn = 0; |
| } |
| if (keylen > 8) |
| keylen = 8; |
| } |
| cc->plaintext = (cipher->number == SSH_CIPHER_NONE); |
| |
| 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; |
| |
| type = (*cipher->evptype)(); |
| |
| EVP_CIPHER_CTX_init(&cc->evp); |
| #ifdef SSH_OLD_EVP |
| if (type->key_len > 0 && type->key_len != keylen) { |
| debug("cipher_init: set keylen (%d -> %d)", |
| type->key_len, keylen); |
| type->key_len = keylen; |
| } |
| EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv, |
| (do_encrypt == CIPHER_ENCRYPT)); |
| #else |
| if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv, |
| (do_encrypt == CIPHER_ENCRYPT)) == 0) |
| fatal("cipher_init: EVP_CipherInit failed for %s", |
| cipher->name); |
| klen = EVP_CIPHER_CTX_key_length(&cc->evp); |
| if (klen > 0 && keylen != klen) { |
| debug2("cipher_init: set keylen (%d -> %d)", klen, keylen); |
| if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0) |
| fatal("cipher_init: set keylen failed (%d -> %d)", |
| klen, keylen); |
| } |
| if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0) |
| fatal("cipher_init: EVP_CipherInit: set key failed for %s", |
| cipher->name); |
| #endif |
| |
| if (cipher->discard_len > 0) { |
| junk = xmalloc(cipher->discard_len); |
| discard = xmalloc(cipher->discard_len); |
| if (EVP_Cipher(&cc->evp, discard, junk, |
| cipher->discard_len) == 0) |
| fatal("evp_crypt: EVP_Cipher failed during discard"); |
| memset(discard, 0, cipher->discard_len); |
| xfree(junk); |
| xfree(discard); |
| } |
| } |
| |
| void |
| cipher_crypt(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); |
| if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0) |
| fatal("evp_crypt: EVP_Cipher failed"); |
| } |
| |
| void |
| cipher_cleanup(CipherContext *cc) |
| { |
| if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0) |
| error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed"); |
| } |
| |
| /* |
| * 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, int do_encrypt) |
| { |
| MD5_CTX md; |
| u_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, do_encrypt); |
| |
| memset(digest, 0, sizeof(digest)); |
| memset(&md, 0, sizeof(md)); |
| } |
| |
| /* |
| * Exports an IV from the CipherContext required to export the key |
| * state back from the unprivileged child to the privileged parent |
| * process. |
| */ |
| |
| int |
| cipher_get_keyiv_len(const CipherContext *cc) |
| { |
| Cipher *c = cc->cipher; |
| int ivlen; |
| |
| if (c->number == SSH_CIPHER_3DES) |
| ivlen = 24; |
| else |
| ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp); |
| return (ivlen); |
| } |
| |
| void |
| cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len) |
| { |
| Cipher *c = cc->cipher; |
| int evplen; |
| |
| switch (c->number) { |
| case SSH_CIPHER_SSH2: |
| case SSH_CIPHER_DES: |
| case SSH_CIPHER_BLOWFISH: |
| evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); |
| if (evplen == 0) |
| return; |
| if (evplen != len) |
| fatal("%s: wrong iv length %d != %d", __func__, |
| evplen, len); |
| #if OPENSSL_VERSION_NUMBER < 0x00907000L |
| if (c->evptype == evp_rijndael) |
| ssh_rijndael_iv(&cc->evp, 0, iv, len); |
| else |
| #endif |
| if (c->evptype == evp_aes_128_ctr) |
| ssh_aes_ctr_iv(&cc->evp, 0, iv, len); |
| else |
| memcpy(iv, cc->evp.iv, len); |
| break; |
| case SSH_CIPHER_3DES: |
| ssh1_3des_iv(&cc->evp, 0, iv, 24); |
| break; |
| default: |
| fatal("%s: bad cipher %d", __func__, c->number); |
| } |
| } |
| |
| void |
| cipher_set_keyiv(CipherContext *cc, u_char *iv) |
| { |
| Cipher *c = cc->cipher; |
| int evplen = 0; |
| |
| switch (c->number) { |
| case SSH_CIPHER_SSH2: |
| case SSH_CIPHER_DES: |
| case SSH_CIPHER_BLOWFISH: |
| evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); |
| if (evplen == 0) |
| return; |
| #if OPENSSL_VERSION_NUMBER < 0x00907000L |
| if (c->evptype == evp_rijndael) |
| ssh_rijndael_iv(&cc->evp, 1, iv, evplen); |
| else |
| #endif |
| if (c->evptype == evp_aes_128_ctr) |
| ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen); |
| else |
| memcpy(cc->evp.iv, iv, evplen); |
| break; |
| case SSH_CIPHER_3DES: |
| ssh1_3des_iv(&cc->evp, 1, iv, 24); |
| break; |
| default: |
| fatal("%s: bad cipher %d", __func__, c->number); |
| } |
| } |
| |
| #if OPENSSL_VERSION_NUMBER < 0x00907000L |
| #define EVP_X_STATE(evp) &(evp).c |
| #define EVP_X_STATE_LEN(evp) sizeof((evp).c) |
| #else |
| #define EVP_X_STATE(evp) (evp).cipher_data |
| #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size |
| #endif |
| |
| int |
| cipher_get_keycontext(const CipherContext *cc, u_char *dat) |
| { |
| Cipher *c = cc->cipher; |
| int plen = 0; |
| |
| if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) { |
| plen = EVP_X_STATE_LEN(cc->evp); |
| if (dat == NULL) |
| return (plen); |
| memcpy(dat, EVP_X_STATE(cc->evp), plen); |
| } |
| return (plen); |
| } |
| |
| void |
| cipher_set_keycontext(CipherContext *cc, u_char *dat) |
| { |
| Cipher *c = cc->cipher; |
| int plen; |
| |
| if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) { |
| plen = EVP_X_STATE_LEN(cc->evp); |
| memcpy(EVP_X_STATE(cc->evp), dat, plen); |
| } |
| } |