1 /*
2 * Copyright (c) 2003 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25 #include "includes.h"
26
27 /* compatibility with old or broken OpenSSL versions */
28 #include "openbsd-compat/openssl-compat.h"
29
30 #ifdef USE_BUILTIN_RIJNDAEL
31 #include <sys/types.h>
32
33 #include <openssl/evp.h>
34
35 #include <stdarg.h>
36 #include <string.h>
37
38 #include "rijndael.h"
39 #include "xmalloc.h"
40 #include "log.h"
41
42 #define RIJNDAEL_BLOCKSIZE 16
43 struct ssh_rijndael_ctx
44 {
45 rijndael_ctx r_ctx;
46 u_char r_iv[RIJNDAEL_BLOCKSIZE];
47 };
48
49 static int
ssh_rijndael_init(EVP_CIPHER_CTX * ctx,const u_char * key,const u_char * iv,int enc)50 ssh_rijndael_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
51 int enc)
52 {
53 struct ssh_rijndael_ctx *c;
54
55 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
56 c = xmalloc(sizeof(*c));
57 EVP_CIPHER_CTX_set_app_data(ctx, c);
58 }
59 if (key != NULL) {
60 if (enc == -1)
61 enc = ctx->encrypt;
62 rijndael_set_key(&c->r_ctx, (u_char *)key,
63 8*EVP_CIPHER_CTX_key_length(ctx), enc);
64 }
65 if (iv != NULL)
66 memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
67 return (1);
68 }
69
70 static int
ssh_rijndael_cbc(EVP_CIPHER_CTX * ctx,u_char * dest,const u_char * src,size_t len)71 ssh_rijndael_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src,
72 size_t len)
73 {
74 struct ssh_rijndael_ctx *c;
75 u_char buf[RIJNDAEL_BLOCKSIZE];
76 u_char *cprev, *cnow, *plain, *ivp;
77 int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
78
79 if (len == 0)
80 return (1);
81 if (len % RIJNDAEL_BLOCKSIZE)
82 fatal("ssh_rijndael_cbc: bad len %d", len);
83 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
84 error("ssh_rijndael_cbc: no context");
85 return (0);
86 }
87 if (ctx->encrypt) {
88 cnow = dest;
89 plain = (u_char *)src;
90 cprev = c->r_iv;
91 for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
92 cnow+=RIJNDAEL_BLOCKSIZE) {
93 for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
94 buf[j] = plain[j] ^ cprev[j];
95 rijndael_encrypt(&c->r_ctx, buf, cnow);
96 cprev = cnow;
97 }
98 memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
99 } else {
100 cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
101 plain = dest+len-RIJNDAEL_BLOCKSIZE;
102
103 memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
104 for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
105 plain-=RIJNDAEL_BLOCKSIZE) {
106 rijndael_decrypt(&c->r_ctx, cnow, plain);
107 ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
108 for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
109 plain[j] ^= ivp[j];
110 }
111 memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
112 }
113 return (1);
114 }
115
116 static int
ssh_rijndael_cleanup(EVP_CIPHER_CTX * ctx)117 ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
118 {
119 struct ssh_rijndael_ctx *c;
120
121 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
122 memset(c, 0, sizeof(*c));
123 free(c);
124 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
125 }
126 return (1);
127 }
128
129 void
ssh_rijndael_iv(EVP_CIPHER_CTX * evp,int doset,u_char * iv,u_int len)130 ssh_rijndael_iv(EVP_CIPHER_CTX *evp, int doset, u_char * iv, u_int len)
131 {
132 struct ssh_rijndael_ctx *c;
133
134 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
135 fatal("ssh_rijndael_iv: no context");
136 if (doset)
137 memcpy(c->r_iv, iv, len);
138 else
139 memcpy(iv, c->r_iv, len);
140 }
141
142 const EVP_CIPHER *
evp_rijndael(void)143 evp_rijndael(void)
144 {
145 static EVP_CIPHER rijndal_cbc;
146
147 memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
148 rijndal_cbc.nid = NID_undef;
149 rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
150 rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
151 rijndal_cbc.key_len = 16;
152 rijndal_cbc.init = ssh_rijndael_init;
153 rijndal_cbc.cleanup = ssh_rijndael_cleanup;
154 rijndal_cbc.do_cipher = ssh_rijndael_cbc;
155 #ifndef SSH_OLD_EVP
156 rijndal_cbc.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH |
157 EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
158 #endif
159 return (&rijndal_cbc);
160 }
161 #endif /* USE_BUILTIN_RIJNDAEL */
162