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Damien Miller86687062014-07-02 15:28:02 +10001/* $OpenBSD: cipher.c,v 1.99 2014/06/24 01:13:21 djm Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11004 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Miller4af51302000-04-16 11:18:38 +10006 *
Damien Millere4340be2000-09-16 13:29:08 +11007 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
Damien Miller4af51302000-04-16 11:18:38 +100012 *
Damien Millere4340be2000-09-16 13:29:08 +110013 *
14 * Copyright (c) 1999 Niels Provos. All rights reserved.
Ben Lindstrom44697232001-07-04 03:32:30 +000015 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110016 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110036 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100037
38#include "includes.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039
Damien Millerd7834352006-08-05 12:39:39 +100040#include <sys/types.h>
41
Damien Millere3476ed2006-07-24 14:13:33 +100042#include <string.h>
Damien Millerd7834352006-08-05 12:39:39 +100043#include <stdarg.h>
Damien Miller0fde8ac2013-11-21 14:12:23 +110044#include <stdio.h>
Damien Millere3476ed2006-07-24 14:13:33 +100045
Ben Lindstrom226cfa02001-01-22 05:34:40 +000046#include "cipher.h"
Damien Miller86687062014-07-02 15:28:02 +100047#include "misc.h"
48#include "sshbuf.h"
49#include "ssherr.h"
Damien Miller4a1c7aa2014-02-04 11:03:36 +110050#include "digest.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100051
Darren Tucker55731712014-07-21 02:24:59 +100052#include "openbsd-compat/openssl-compat.h"
53
Damien Miller1f0311c2014-05-15 14:24:09 +100054#ifdef WITH_SSH1
Damien Miller3a3261f2003-05-15 13:37:19 +100055extern const EVP_CIPHER *evp_ssh1_bf(void);
56extern const EVP_CIPHER *evp_ssh1_3des(void);
Damien Miller86687062014-07-02 15:28:02 +100057extern int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
Damien Miller1f0311c2014-05-15 14:24:09 +100058#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +100059
Damien Miller86687062014-07-02 15:28:02 +100060struct sshcipher {
Damien Miller963f6b22002-02-19 15:21:23 +110061 char *name;
62 int number; /* for ssh1 only */
63 u_int block_size;
64 u_int key_len;
Damien Millerd522c682013-01-09 16:42:47 +110065 u_int iv_len; /* defaults to block_size */
66 u_int auth_len;
Damien Miller3710f272005-05-26 12:19:17 +100067 u_int discard_len;
Damien Miller0fde8ac2013-11-21 14:12:23 +110068 u_int flags;
69#define CFLAG_CBC (1<<0)
70#define CFLAG_CHACHAPOLY (1<<1)
Damien Miller1f0311c2014-05-15 14:24:09 +100071#define CFLAG_AESCTR (1<<2)
72#define CFLAG_NONE (1<<3)
73#ifdef WITH_OPENSSL
Ben Lindstrom6a246412002-06-06 19:48:16 +000074 const EVP_CIPHER *(*evptype)(void);
Damien Miller1f0311c2014-05-15 14:24:09 +100075#else
76 void *ignored;
77#endif
Damien Millerea111192013-04-23 19:24:32 +100078};
79
Damien Miller86687062014-07-02 15:28:02 +100080static const struct sshcipher ciphers[] = {
Damien Miller1f0311c2014-05-15 14:24:09 +100081#ifdef WITH_SSH1
Damien Miller1d75abf2013-01-09 16:12:19 +110082 { "des", SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc },
83 { "3des", SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des },
84 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, 0, 0, 1, evp_ssh1_bf },
Damien Miller86687062014-07-02 15:28:02 +100085#endif /* WITH_SSH1 */
Damien Miller1f0311c2014-05-15 14:24:09 +100086#ifdef WITH_OPENSSL
87 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null },
Damien Miller1d75abf2013-01-09 16:12:19 +110088 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc },
89 { "blowfish-cbc",
90 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc },
91 { "cast128-cbc",
92 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc },
93 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 },
94 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 },
95 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 },
96 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc },
97 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc },
98 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
99 { "rijndael-cbc@lysator.liu.se",
100 SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc },
101 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr },
102 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr },
103 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr },
Damien Miller86687062014-07-02 15:28:02 +1000104# ifdef OPENSSL_HAVE_EVPGCM
Damien Miller1d75abf2013-01-09 16:12:19 +1100105 { "aes128-gcm@openssh.com",
106 SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm },
107 { "aes256-gcm@openssh.com",
108 SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm },
Damien Miller86687062014-07-02 15:28:02 +1000109# endif /* OPENSSL_HAVE_EVPGCM */
Damien Miller1f0311c2014-05-15 14:24:09 +1000110#else /* WITH_OPENSSL */
111 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL },
112 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL },
113 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL },
114 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL },
115#endif /* WITH_OPENSSL */
Damien Miller0fde8ac2013-11-21 14:12:23 +1100116 { "chacha20-poly1305@openssh.com",
117 SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL },
Damien Miller86687062014-07-02 15:28:02 +1000118
Damien Miller1d75abf2013-01-09 16:12:19 +1100119 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000120};
121
Damien Miller874d77b2000-10-14 16:23:11 +1100122/*--*/
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000123
Damien Miller86687062014-07-02 15:28:02 +1000124/* Returns a comma-separated list of supported ciphers. */
Damien Millerea111192013-04-23 19:24:32 +1000125char *
Damien Miller0fde8ac2013-11-21 14:12:23 +1100126cipher_alg_list(char sep, int auth_only)
Damien Millerea111192013-04-23 19:24:32 +1000127{
Damien Miller86687062014-07-02 15:28:02 +1000128 char *tmp, *ret = NULL;
Damien Millerea111192013-04-23 19:24:32 +1000129 size_t nlen, rlen = 0;
Damien Miller86687062014-07-02 15:28:02 +1000130 const struct sshcipher *c;
Damien Millerea111192013-04-23 19:24:32 +1000131
132 for (c = ciphers; c->name != NULL; c++) {
133 if (c->number != SSH_CIPHER_SSH2)
134 continue;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100135 if (auth_only && c->auth_len == 0)
136 continue;
Damien Millerea111192013-04-23 19:24:32 +1000137 if (ret != NULL)
Damien Miller690d9892013-11-08 12:16:49 +1100138 ret[rlen++] = sep;
Damien Millerea111192013-04-23 19:24:32 +1000139 nlen = strlen(c->name);
Damien Miller86687062014-07-02 15:28:02 +1000140 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
141 free(ret);
142 return NULL;
143 }
144 ret = tmp;
Damien Millerea111192013-04-23 19:24:32 +1000145 memcpy(ret + rlen, c->name, nlen + 1);
146 rlen += nlen;
147 }
148 return ret;
149}
150
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000151u_int
Damien Miller86687062014-07-02 15:28:02 +1000152cipher_blocksize(const struct sshcipher *c)
Damien Miller963f6b22002-02-19 15:21:23 +1100153{
154 return (c->block_size);
155}
Ben Lindstrom836f0e92002-06-23 21:21:30 +0000156
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000157u_int
Damien Miller86687062014-07-02 15:28:02 +1000158cipher_keylen(const struct sshcipher *c)
Damien Miller963f6b22002-02-19 15:21:23 +1100159{
160 return (c->key_len);
161}
Ben Lindstrom836f0e92002-06-23 21:21:30 +0000162
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000163u_int
Damien Miller86687062014-07-02 15:28:02 +1000164cipher_seclen(const struct sshcipher *c)
Damien Miller76eea4a2014-01-26 09:37:25 +1100165{
166 if (strcmp("3des-cbc", c->name) == 0)
167 return 14;
168 return cipher_keylen(c);
169}
170
171u_int
Damien Miller86687062014-07-02 15:28:02 +1000172cipher_authlen(const struct sshcipher *c)
Damien Miller1d75abf2013-01-09 16:12:19 +1100173{
174 return (c->auth_len);
175}
176
177u_int
Damien Miller86687062014-07-02 15:28:02 +1000178cipher_ivlen(const struct sshcipher *c)
Damien Miller1d75abf2013-01-09 16:12:19 +1100179{
Damien Miller0fde8ac2013-11-21 14:12:23 +1100180 /*
181 * Default is cipher block size, except for chacha20+poly1305 that
182 * needs no IV. XXX make iv_len == -1 default?
183 */
184 return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ?
185 c->iv_len : c->block_size;
Damien Miller1d75abf2013-01-09 16:12:19 +1100186}
187
188u_int
Damien Miller86687062014-07-02 15:28:02 +1000189cipher_get_number(const struct sshcipher *c)
Ben Lindstrom212faca2002-03-22 01:39:44 +0000190{
191 return (c->number);
192}
Damien Miller963f6b22002-02-19 15:21:23 +1100193
Ben Lindstrom46c16222000-12-22 01:43:59 +0000194u_int
Damien Miller86687062014-07-02 15:28:02 +1000195cipher_is_cbc(const struct sshcipher *c)
Damien Miller13ae44c2009-01-28 16:38:41 +1100196{
Damien Miller0fde8ac2013-11-21 14:12:23 +1100197 return (c->flags & CFLAG_CBC) != 0;
Damien Miller13ae44c2009-01-28 16:38:41 +1100198}
199
200u_int
Damien Miller874d77b2000-10-14 16:23:11 +1100201cipher_mask_ssh1(int client)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000202{
Ben Lindstrom46c16222000-12-22 01:43:59 +0000203 u_int mask = 0;
Damien Miller9f0f5c62001-12-21 14:45:46 +1100204 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
Damien Miller95def091999-11-25 00:26:21 +1100205 mask |= 1 << SSH_CIPHER_BLOWFISH;
Damien Miller874d77b2000-10-14 16:23:11 +1100206 if (client) {
207 mask |= 1 << SSH_CIPHER_DES;
208 }
Damien Miller1383bd82000-04-06 12:32:37 +1000209 return mask;
210}
Damien Miller874d77b2000-10-14 16:23:11 +1100211
Damien Miller86687062014-07-02 15:28:02 +1000212const struct sshcipher *
Damien Miller874d77b2000-10-14 16:23:11 +1100213cipher_by_name(const char *name)
Damien Miller1383bd82000-04-06 12:32:37 +1000214{
Damien Miller86687062014-07-02 15:28:02 +1000215 const struct sshcipher *c;
Damien Miller874d77b2000-10-14 16:23:11 +1100216 for (c = ciphers; c->name != NULL; c++)
Darren Tucker660db782005-01-24 21:57:11 +1100217 if (strcmp(c->name, name) == 0)
Damien Miller874d77b2000-10-14 16:23:11 +1100218 return c;
219 return NULL;
Damien Miller1383bd82000-04-06 12:32:37 +1000220}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000221
Damien Miller86687062014-07-02 15:28:02 +1000222const struct sshcipher *
Damien Miller874d77b2000-10-14 16:23:11 +1100223cipher_by_number(int id)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000224{
Damien Miller86687062014-07-02 15:28:02 +1000225 const struct sshcipher *c;
Damien Miller874d77b2000-10-14 16:23:11 +1100226 for (c = ciphers; c->name != NULL; c++)
227 if (c->number == id)
228 return c;
229 return NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000230}
231
Damien Miller78928792000-04-12 20:17:38 +1000232#define CIPHER_SEP ","
233int
234ciphers_valid(const char *names)
235{
Damien Miller86687062014-07-02 15:28:02 +1000236 const struct sshcipher *c;
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000237 char *cipher_list, *cp;
Damien Miller78928792000-04-12 20:17:38 +1000238 char *p;
Damien Miller78928792000-04-12 20:17:38 +1000239
Damien Millerb1715dc2000-05-30 13:44:51 +1000240 if (names == NULL || strcmp(names, "") == 0)
Damien Miller78928792000-04-12 20:17:38 +1000241 return 0;
Damien Miller86687062014-07-02 15:28:02 +1000242 if ((cipher_list = cp = strdup(names)) == NULL)
243 return 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100244 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
Damien Miller9f0f5c62001-12-21 14:45:46 +1100245 (p = strsep(&cp, CIPHER_SEP))) {
Damien Miller874d77b2000-10-14 16:23:11 +1100246 c = cipher_by_name(p);
247 if (c == NULL || c->number != SSH_CIPHER_SSH2) {
Darren Tuckera627d422013-06-02 07:31:17 +1000248 free(cipher_list);
Damien Miller78928792000-04-12 20:17:38 +1000249 return 0;
250 }
251 }
Darren Tuckera627d422013-06-02 07:31:17 +1000252 free(cipher_list);
Damien Miller78928792000-04-12 20:17:38 +1000253 return 1;
254}
255
Damien Miller5428f641999-11-25 11:54:57 +1100256/*
257 * Parses the name of the cipher. Returns the number of the corresponding
258 * cipher, or -1 on error.
259 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000260
261int
262cipher_number(const char *name)
263{
Damien Miller86687062014-07-02 15:28:02 +1000264 const struct sshcipher *c;
Damien Millerb1715dc2000-05-30 13:44:51 +1000265 if (name == NULL)
266 return -1;
Darren Tucker660db782005-01-24 21:57:11 +1100267 for (c = ciphers; c->name != NULL; c++)
268 if (strcasecmp(c->name, name) == 0)
269 return c->number;
270 return -1;
Damien Miller874d77b2000-10-14 16:23:11 +1100271}
272
273char *
274cipher_name(int id)
275{
Damien Miller86687062014-07-02 15:28:02 +1000276 const struct sshcipher *c = cipher_by_number(id);
Damien Miller874d77b2000-10-14 16:23:11 +1100277 return (c==NULL) ? "<unknown>" : c->name;
278}
279
Damien Miller86687062014-07-02 15:28:02 +1000280const char *
281cipher_warning_message(const struct sshcipher_ctx *cc)
282{
283 if (cc == NULL || cc->cipher == NULL)
284 return NULL;
285 if (cc->cipher->number == SSH_CIPHER_DES)
286 return "use of DES is strongly discouraged due to "
287 "cryptographic weaknesses";
288 return NULL;
289}
290
291int
292cipher_init(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
Damien Miller21cf4e02002-02-19 15:26:42 +1100293 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000294 int do_encrypt)
Damien Miller874d77b2000-10-14 16:23:11 +1100295{
Damien Miller1f0311c2014-05-15 14:24:09 +1000296#ifdef WITH_OPENSSL
Damien Miller86687062014-07-02 15:28:02 +1000297 int ret = SSH_ERR_INTERNAL_ERROR;
Damien Miller21cf4e02002-02-19 15:26:42 +1100298 const EVP_CIPHER *type;
299 int klen;
Damien Miller3710f272005-05-26 12:19:17 +1000300 u_char *junk, *discard;
Damien Miller21cf4e02002-02-19 15:26:42 +1100301
302 if (cipher->number == SSH_CIPHER_DES) {
Damien Miller21cf4e02002-02-19 15:26:42 +1100303 if (keylen > 8)
304 keylen = 8;
305 }
Damien Miller1f0311c2014-05-15 14:24:09 +1000306#endif
Damien Miller21cf4e02002-02-19 15:26:42 +1100307 cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
Damien Miller1d75abf2013-01-09 16:12:19 +1100308 cc->encrypt = do_encrypt;
Damien Miller21cf4e02002-02-19 15:26:42 +1100309
Damien Miller86687062014-07-02 15:28:02 +1000310 if (keylen < cipher->key_len ||
311 (iv != NULL && ivlen < cipher_ivlen(cipher)))
312 return SSH_ERR_INVALID_ARGUMENT;
Damien Miller21cf4e02002-02-19 15:26:42 +1100313
Damien Miller86687062014-07-02 15:28:02 +1000314 cc->cipher = cipher;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100315 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
Damien Miller86687062014-07-02 15:28:02 +1000316 return chachapoly_init(&cc->cp_ctx, key, keylen);
Damien Miller0fde8ac2013-11-21 14:12:23 +1100317 }
Damien Miller1f0311c2014-05-15 14:24:09 +1000318#ifndef WITH_OPENSSL
319 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
320 aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen);
321 aesctr_ivsetup(&cc->ac_ctx, iv);
Damien Miller86687062014-07-02 15:28:02 +1000322 return 0;
Damien Miller1f0311c2014-05-15 14:24:09 +1000323 }
324 if ((cc->cipher->flags & CFLAG_NONE) != 0)
Damien Miller86687062014-07-02 15:28:02 +1000325 return 0;
326 return SSH_ERR_INVALID_ARGUMENT;
Damien Miller1f0311c2014-05-15 14:24:09 +1000327#else
Damien Miller21cf4e02002-02-19 15:26:42 +1100328 type = (*cipher->evptype)();
Damien Miller21cf4e02002-02-19 15:26:42 +1100329 EVP_CIPHER_CTX_init(&cc->evp);
330 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
Damien Miller86687062014-07-02 15:28:02 +1000331 (do_encrypt == CIPHER_ENCRYPT)) == 0) {
332 ret = SSH_ERR_LIBCRYPTO_ERROR;
333 goto bad;
334 }
Damien Miller1d75abf2013-01-09 16:12:19 +1100335 if (cipher_authlen(cipher) &&
336 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_IV_FIXED,
Damien Miller86687062014-07-02 15:28:02 +1000337 -1, (u_char *)iv)) {
338 ret = SSH_ERR_LIBCRYPTO_ERROR;
339 goto bad;
340 }
Damien Miller21cf4e02002-02-19 15:26:42 +1100341 klen = EVP_CIPHER_CTX_key_length(&cc->evp);
Damien Millereccb9de2005-06-17 12:59:34 +1000342 if (klen > 0 && keylen != (u_int)klen) {
Damien Miller86687062014-07-02 15:28:02 +1000343 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0) {
344 ret = SSH_ERR_LIBCRYPTO_ERROR;
345 goto bad;
346 }
Damien Miller21cf4e02002-02-19 15:26:42 +1100347 }
Damien Miller86687062014-07-02 15:28:02 +1000348 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0) {
349 ret = SSH_ERR_LIBCRYPTO_ERROR;
350 goto bad;
351 }
Damien Miller3710f272005-05-26 12:19:17 +1000352
Damien Miller46d38de2005-07-17 17:02:09 +1000353 if (cipher->discard_len > 0) {
Damien Miller86687062014-07-02 15:28:02 +1000354 if ((junk = malloc(cipher->discard_len)) == NULL ||
355 (discard = malloc(cipher->discard_len)) == NULL) {
356 if (junk != NULL)
357 free(junk);
358 ret = SSH_ERR_ALLOC_FAIL;
359 goto bad;
360 }
361 ret = EVP_Cipher(&cc->evp, discard, junk, cipher->discard_len);
Damien Millera5103f42014-02-04 11:20:14 +1100362 explicit_bzero(discard, cipher->discard_len);
Darren Tuckera627d422013-06-02 07:31:17 +1000363 free(junk);
364 free(discard);
Damien Miller86687062014-07-02 15:28:02 +1000365 if (ret != 1) {
366 ret = SSH_ERR_LIBCRYPTO_ERROR;
367 bad:
368 EVP_CIPHER_CTX_cleanup(&cc->evp);
369 return ret;
370 }
Damien Miller3710f272005-05-26 12:19:17 +1000371 }
Damien Miller1f0311c2014-05-15 14:24:09 +1000372#endif
Damien Miller86687062014-07-02 15:28:02 +1000373 return 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100374}
375
Damien Milleraf43a7a2012-12-12 10:46:31 +1100376/*
377 * cipher_crypt() operates as following:
378 * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'.
379 * Theses bytes are treated as additional authenticated data for
380 * authenticated encryption modes.
381 * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'.
Damien Miller1d75abf2013-01-09 16:12:19 +1100382 * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag.
383 * This tag is written on encryption and verified on decryption.
Damien Milleraf43a7a2012-12-12 10:46:31 +1100384 * Both 'aadlen' and 'authlen' can be set to 0.
385 */
Damien Millerbcd00ab2013-12-07 10:41:55 +1100386int
Damien Miller86687062014-07-02 15:28:02 +1000387cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest,
388 const u_char *src, u_int len, u_int aadlen, u_int authlen)
Damien Miller874d77b2000-10-14 16:23:11 +1100389{
Damien Miller86687062014-07-02 15:28:02 +1000390 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
391 return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src,
392 len, aadlen, authlen, cc->encrypt);
393 }
Damien Miller1f0311c2014-05-15 14:24:09 +1000394#ifndef WITH_OPENSSL
395 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) {
396 if (aadlen)
397 memcpy(dest, src, aadlen);
398 aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen,
399 dest + aadlen, len);
400 return 0;
401 }
402 if ((cc->cipher->flags & CFLAG_NONE) != 0) {
403 memcpy(dest, src, aadlen + len);
404 return 0;
405 }
Damien Miller86687062014-07-02 15:28:02 +1000406 return SSH_ERR_INVALID_ARGUMENT;
Damien Miller1f0311c2014-05-15 14:24:09 +1000407#else
Damien Miller1d75abf2013-01-09 16:12:19 +1100408 if (authlen) {
409 u_char lastiv[1];
410
411 if (authlen != cipher_authlen(cc->cipher))
Damien Miller86687062014-07-02 15:28:02 +1000412 return SSH_ERR_INVALID_ARGUMENT;
Damien Miller1d75abf2013-01-09 16:12:19 +1100413 /* increment IV */
414 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN,
415 1, lastiv))
Damien Miller86687062014-07-02 15:28:02 +1000416 return SSH_ERR_LIBCRYPTO_ERROR;
Damien Miller1d75abf2013-01-09 16:12:19 +1100417 /* set tag on decyption */
418 if (!cc->encrypt &&
419 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_TAG,
420 authlen, (u_char *)src + aadlen + len))
Damien Miller86687062014-07-02 15:28:02 +1000421 return SSH_ERR_LIBCRYPTO_ERROR;
Damien Miller1d75abf2013-01-09 16:12:19 +1100422 }
423 if (aadlen) {
424 if (authlen &&
425 EVP_Cipher(&cc->evp, NULL, (u_char *)src, aadlen) < 0)
Damien Miller86687062014-07-02 15:28:02 +1000426 return SSH_ERR_LIBCRYPTO_ERROR;
Damien Milleraf43a7a2012-12-12 10:46:31 +1100427 memcpy(dest, src, aadlen);
Damien Miller1d75abf2013-01-09 16:12:19 +1100428 }
Damien Miller874d77b2000-10-14 16:23:11 +1100429 if (len % cc->cipher->block_size)
Damien Miller86687062014-07-02 15:28:02 +1000430 return SSH_ERR_INVALID_ARGUMENT;
Damien Milleraf43a7a2012-12-12 10:46:31 +1100431 if (EVP_Cipher(&cc->evp, dest + aadlen, (u_char *)src + aadlen,
432 len) < 0)
Damien Miller86687062014-07-02 15:28:02 +1000433 return SSH_ERR_LIBCRYPTO_ERROR;
Damien Miller1d75abf2013-01-09 16:12:19 +1100434 if (authlen) {
435 /* compute tag (on encrypt) or verify tag (on decrypt) */
Damien Miller86687062014-07-02 15:28:02 +1000436 if (EVP_Cipher(&cc->evp, NULL, NULL, 0) < 0)
437 return cc->encrypt ?
438 SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID;
Damien Miller1d75abf2013-01-09 16:12:19 +1100439 if (cc->encrypt &&
440 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_GET_TAG,
441 authlen, dest + aadlen + len))
Damien Miller86687062014-07-02 15:28:02 +1000442 return SSH_ERR_LIBCRYPTO_ERROR;
Damien Miller1d75abf2013-01-09 16:12:19 +1100443 }
Damien Millerbcd00ab2013-12-07 10:41:55 +1100444 return 0;
Damien Miller1f0311c2014-05-15 14:24:09 +1000445#endif
Damien Miller874d77b2000-10-14 16:23:11 +1100446}
447
Damien Miller0fde8ac2013-11-21 14:12:23 +1100448/* Extract the packet length, including any decryption necessary beforehand */
449int
Damien Miller86687062014-07-02 15:28:02 +1000450cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr,
Damien Miller0fde8ac2013-11-21 14:12:23 +1100451 const u_char *cp, u_int len)
452{
453 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
454 return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr,
455 cp, len);
456 if (len < 4)
Damien Miller86687062014-07-02 15:28:02 +1000457 return SSH_ERR_MESSAGE_INCOMPLETE;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100458 *plenp = get_u32(cp);
459 return 0;
460}
461
Damien Miller86687062014-07-02 15:28:02 +1000462int
463cipher_cleanup(struct sshcipher_ctx *cc)
Damien Miller874d77b2000-10-14 16:23:11 +1100464{
Damien Miller86687062014-07-02 15:28:02 +1000465 if (cc == NULL || cc->cipher == NULL)
466 return 0;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100467 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
Damien Millera5103f42014-02-04 11:20:14 +1100468 explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx));
Damien Miller1f0311c2014-05-15 14:24:09 +1000469 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0)
470 explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx));
471#ifdef WITH_OPENSSL
Damien Miller0fde8ac2013-11-21 14:12:23 +1100472 else if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
Damien Miller86687062014-07-02 15:28:02 +1000473 return SSH_ERR_LIBCRYPTO_ERROR;
Damien Miller1f0311c2014-05-15 14:24:09 +1000474#endif
Damien Miller86687062014-07-02 15:28:02 +1000475 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000476}
477
Damien Miller5428f641999-11-25 11:54:57 +1100478/*
479 * Selects the cipher, and keys if by computing the MD5 checksum of the
480 * passphrase and using the resulting 16 bytes as the key.
481 */
Damien Miller86687062014-07-02 15:28:02 +1000482int
483cipher_set_key_string(struct sshcipher_ctx *cc, const struct sshcipher *cipher,
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000484 const char *passphrase, int do_encrypt)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000485{
Ben Lindstrom46c16222000-12-22 01:43:59 +0000486 u_char digest[16];
Damien Miller86687062014-07-02 15:28:02 +1000487 int r = SSH_ERR_INTERNAL_ERROR;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000488
Damien Miller86687062014-07-02 15:28:02 +1000489 if ((r = ssh_digest_memory(SSH_DIGEST_MD5,
490 passphrase, strlen(passphrase),
491 digest, sizeof(digest))) != 0)
492 goto out;
Damien Miller95def091999-11-25 00:26:21 +1100493
Damien Miller86687062014-07-02 15:28:02 +1000494 r = cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
495 out:
Damien Millera5103f42014-02-04 11:20:14 +1100496 explicit_bzero(digest, sizeof(digest));
Damien Miller86687062014-07-02 15:28:02 +1000497 return r;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000498}
Damien Miller21cf4e02002-02-19 15:26:42 +1100499
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000500/*
Damien Miller86687062014-07-02 15:28:02 +1000501 * Exports an IV from the sshcipher_ctx required to export the key
Ben Lindstrom212faca2002-03-22 01:39:44 +0000502 * state back from the unprivileged child to the privileged parent
503 * process.
504 */
Ben Lindstrom212faca2002-03-22 01:39:44 +0000505int
Damien Miller86687062014-07-02 15:28:02 +1000506cipher_get_keyiv_len(const struct sshcipher_ctx *cc)
Ben Lindstrom212faca2002-03-22 01:39:44 +0000507{
Damien Miller86687062014-07-02 15:28:02 +1000508 const struct sshcipher *c = cc->cipher;
Damien Miller1f0311c2014-05-15 14:24:09 +1000509 int ivlen = 0;
Ben Lindstrom212faca2002-03-22 01:39:44 +0000510
511 if (c->number == SSH_CIPHER_3DES)
512 ivlen = 24;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100513 else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
514 ivlen = 0;
Damien Miller1f0311c2014-05-15 14:24:09 +1000515#ifdef WITH_OPENSSL
Ben Lindstrom212faca2002-03-22 01:39:44 +0000516 else
517 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
Damien Miller86687062014-07-02 15:28:02 +1000518#endif /* WITH_OPENSSL */
Ben Lindstrom212faca2002-03-22 01:39:44 +0000519 return (ivlen);
520}
521
Damien Miller86687062014-07-02 15:28:02 +1000522int
523cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len)
Ben Lindstrom212faca2002-03-22 01:39:44 +0000524{
Damien Miller86687062014-07-02 15:28:02 +1000525 const struct sshcipher *c = cc->cipher;
Damien Miller1f0311c2014-05-15 14:24:09 +1000526#ifdef WITH_OPENSSL
Damien Miller86687062014-07-02 15:28:02 +1000527 int evplen;
Damien Miller1f0311c2014-05-15 14:24:09 +1000528#endif
Ben Lindstrom212faca2002-03-22 01:39:44 +0000529
Damien Miller0fde8ac2013-11-21 14:12:23 +1100530 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) {
531 if (len != 0)
Damien Miller86687062014-07-02 15:28:02 +1000532 return SSH_ERR_INVALID_ARGUMENT;
533 return 0;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100534 }
Damien Miller1f0311c2014-05-15 14:24:09 +1000535 if ((cc->cipher->flags & CFLAG_NONE) != 0)
Damien Miller86687062014-07-02 15:28:02 +1000536 return 0;
Damien Miller0fde8ac2013-11-21 14:12:23 +1100537
Ben Lindstrom212faca2002-03-22 01:39:44 +0000538 switch (c->number) {
Damien Miller1f0311c2014-05-15 14:24:09 +1000539#ifdef WITH_OPENSSL
Ben Lindstrom212faca2002-03-22 01:39:44 +0000540 case SSH_CIPHER_SSH2:
541 case SSH_CIPHER_DES:
542 case SSH_CIPHER_BLOWFISH:
543 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
544 if (evplen == 0)
Damien Miller86687062014-07-02 15:28:02 +1000545 return 0;
546 else if (evplen < 0)
547 return SSH_ERR_LIBCRYPTO_ERROR;
548 if ((u_int)evplen != len)
549 return SSH_ERR_INVALID_ARGUMENT;
Darren Tucker55731712014-07-21 02:24:59 +1000550#ifndef OPENSSL_HAVE_EVPCTR
551 if (c->evptype == evp_aes_128_ctr)
552 ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
553 else
554#endif
Damien Millereae88742014-05-27 14:27:02 +1000555 if (cipher_authlen(c)) {
Damien Miller86687062014-07-02 15:28:02 +1000556 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN,
557 len, iv))
558 return SSH_ERR_LIBCRYPTO_ERROR;
559 } else
560 memcpy(iv, cc->evp.iv, len);
Ben Lindstrom212faca2002-03-22 01:39:44 +0000561 break;
Damien Miller86687062014-07-02 15:28:02 +1000562#endif
Damien Miller1f0311c2014-05-15 14:24:09 +1000563#ifdef WITH_SSH1
Damien Millera201bb32003-05-14 13:41:23 +1000564 case SSH_CIPHER_3DES:
Damien Miller86687062014-07-02 15:28:02 +1000565 return ssh1_3des_iv(&cc->evp, 0, iv, 24);
566#endif
Ben Lindstrom212faca2002-03-22 01:39:44 +0000567 default:
Damien Miller86687062014-07-02 15:28:02 +1000568 return SSH_ERR_INVALID_ARGUMENT;
Ben Lindstrom212faca2002-03-22 01:39:44 +0000569 }
Damien Miller86687062014-07-02 15:28:02 +1000570 return 0;
Ben Lindstrom212faca2002-03-22 01:39:44 +0000571}
572
Ben Lindstrom212faca2002-03-22 01:39:44 +0000573int
Damien Miller86687062014-07-02 15:28:02 +1000574cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv)
575{
576 const struct sshcipher *c = cc->cipher;
577#ifdef WITH_OPENSSL
578 int evplen = 0;
579#endif
580
581 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0)
582 return 0;
583 if ((cc->cipher->flags & CFLAG_NONE) != 0)
584 return 0;
585
586 switch (c->number) {
587#ifdef WITH_OPENSSL
588 case SSH_CIPHER_SSH2:
589 case SSH_CIPHER_DES:
590 case SSH_CIPHER_BLOWFISH:
591 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
592 if (evplen <= 0)
593 return SSH_ERR_LIBCRYPTO_ERROR;
594 if (cipher_authlen(c)) {
595 /* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */
596 if (!EVP_CIPHER_CTX_ctrl(&cc->evp,
597 EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv))
598 return SSH_ERR_LIBCRYPTO_ERROR;
599 } else
600 memcpy(cc->evp.iv, iv, evplen);
601 break;
602#endif
603#ifdef WITH_SSH1
604 case SSH_CIPHER_3DES:
605 return ssh1_3des_iv(&cc->evp, 1, (u_char *)iv, 24);
606#endif
607 default:
608 return SSH_ERR_INVALID_ARGUMENT;
609 }
610 return 0;
611}
612
613#ifdef WITH_OPENSSL
614#define EVP_X_STATE(evp) (evp).cipher_data
615#define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
616#endif
617
618int
619cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat)
Ben Lindstrom212faca2002-03-22 01:39:44 +0000620{
Damien Miller1f0311c2014-05-15 14:24:09 +1000621#ifdef WITH_OPENSSL
Damien Miller86687062014-07-02 15:28:02 +1000622 const struct sshcipher *c = cc->cipher;
Ben Lindstrom402c6cc2002-06-21 00:43:42 +0000623 int plen = 0;
Ben Lindstrom212faca2002-03-22 01:39:44 +0000624
Damien Millerf0a8ded2013-02-12 11:00:34 +1100625 if (c->evptype == EVP_rc4) {
Ben Lindstrom402c6cc2002-06-21 00:43:42 +0000626 plen = EVP_X_STATE_LEN(cc->evp);
Ben Lindstrom212faca2002-03-22 01:39:44 +0000627 if (dat == NULL)
Ben Lindstrom402c6cc2002-06-21 00:43:42 +0000628 return (plen);
629 memcpy(dat, EVP_X_STATE(cc->evp), plen);
Ben Lindstrom212faca2002-03-22 01:39:44 +0000630 }
Ben Lindstrom212faca2002-03-22 01:39:44 +0000631 return (plen);
Damien Miller1f0311c2014-05-15 14:24:09 +1000632#else
Damien Miller86687062014-07-02 15:28:02 +1000633 return 0;
Damien Miller1f0311c2014-05-15 14:24:09 +1000634#endif
Ben Lindstrom212faca2002-03-22 01:39:44 +0000635}
636
637void
Damien Miller86687062014-07-02 15:28:02 +1000638cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat)
Ben Lindstrom212faca2002-03-22 01:39:44 +0000639{
Damien Miller1f0311c2014-05-15 14:24:09 +1000640#ifdef WITH_OPENSSL
Damien Miller86687062014-07-02 15:28:02 +1000641 const struct sshcipher *c = cc->cipher;
Ben Lindstrom212faca2002-03-22 01:39:44 +0000642 int plen;
643
Damien Millerf0a8ded2013-02-12 11:00:34 +1100644 if (c->evptype == EVP_rc4) {
Ben Lindstrom212faca2002-03-22 01:39:44 +0000645 plen = EVP_X_STATE_LEN(cc->evp);
646 memcpy(EVP_X_STATE(cc->evp), dat, plen);
647 }
Damien Miller1f0311c2014-05-15 14:24:09 +1000648#endif
Damien Miller21cf4e02002-02-19 15:26:42 +1100649}