Annotation of src/usr.bin/ssh/cipher-aes.c, Revision 1.2
1.1 markus 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:
1.2 ! djm 25: #include "includes.h"
1.1 markus 26: #if OPENSSL_VERSION_NUMBER < 0x00907000L
1.2 ! djm 27: RCSID("$OpenBSD: cipher-aes.c,v 1.1 2003/05/15 03:08:29 markus Exp $");
1.1 markus 28:
29: #include <openssl/evp.h>
30: #include "rijndael.h"
31: #include "xmalloc.h"
32: #include "log.h"
33:
34: #define RIJNDAEL_BLOCKSIZE 16
35: struct ssh_rijndael_ctx
36: {
37: rijndael_ctx r_ctx;
38: u_char r_iv[RIJNDAEL_BLOCKSIZE];
39: };
40:
41: const EVP_CIPHER * evp_rijndael(void);
42: void ssh_rijndael_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
43:
44: static int
45: ssh_rijndael_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
46: int enc)
47: {
48: struct ssh_rijndael_ctx *c;
49:
50: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
51: c = xmalloc(sizeof(*c));
52: EVP_CIPHER_CTX_set_app_data(ctx, c);
53: }
54: if (key != NULL) {
55: if (enc == -1)
56: enc = ctx->encrypt;
57: rijndael_set_key(&c->r_ctx, (u_char *)key,
58: 8*EVP_CIPHER_CTX_key_length(ctx), enc);
59: }
60: if (iv != NULL)
61: memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
62: return (1);
63: }
64:
65: static int
66: ssh_rijndael_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src,
67: u_int len)
68: {
69: struct ssh_rijndael_ctx *c;
70: u_char buf[RIJNDAEL_BLOCKSIZE];
71: u_char *cprev, *cnow, *plain, *ivp;
72: int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
73:
74: if (len == 0)
75: return (1);
76: if (len % RIJNDAEL_BLOCKSIZE)
77: fatal("ssh_rijndael_cbc: bad len %d", len);
78: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
79: error("ssh_rijndael_cbc: no context");
80: return (0);
81: }
82: if (ctx->encrypt) {
83: cnow = dest;
84: plain = (u_char *)src;
85: cprev = c->r_iv;
86: for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
87: cnow+=RIJNDAEL_BLOCKSIZE) {
88: for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
89: buf[j] = plain[j] ^ cprev[j];
90: rijndael_encrypt(&c->r_ctx, buf, cnow);
91: cprev = cnow;
92: }
93: memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
94: } else {
95: cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
96: plain = dest+len-RIJNDAEL_BLOCKSIZE;
97:
98: memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
99: for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
100: plain-=RIJNDAEL_BLOCKSIZE) {
101: rijndael_decrypt(&c->r_ctx, cnow, plain);
102: ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
103: for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
104: plain[j] ^= ivp[j];
105: }
106: memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
107: }
108: return (1);
109: }
110:
111: static int
112: ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
113: {
114: struct ssh_rijndael_ctx *c;
115:
116: if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
117: memset(c, 0, sizeof(*c));
118: xfree(c);
119: EVP_CIPHER_CTX_set_app_data(ctx, NULL);
120: }
121: return (1);
122: }
123:
124: void
125: ssh_rijndael_iv(EVP_CIPHER_CTX *evp, int doset, u_char * iv, u_int len)
126: {
127: struct ssh_rijndael_ctx *c;
128:
129: if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
130: fatal("ssh_rijndael_iv: no context");
131: if (doset)
132: memcpy(c->r_iv, iv, len);
133: else
134: memcpy(iv, c->r_iv, len);
135: }
136:
137: const EVP_CIPHER *
138: evp_rijndael(void)
139: {
140: static EVP_CIPHER rijndal_cbc;
141:
142: memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
143: rijndal_cbc.nid = NID_undef;
144: rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
145: rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
146: rijndal_cbc.key_len = 16;
147: rijndal_cbc.init = ssh_rijndael_init;
148: rijndal_cbc.cleanup = ssh_rijndael_cleanup;
149: rijndal_cbc.do_cipher = ssh_rijndael_cbc;
150: rijndal_cbc.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH |
151: EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
152: return (&rijndal_cbc);
153: }
154: #endif
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