crypto/openssh-3.8.1p1/cipher-aes.c

   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 #if OPENSSL_VERSION_NUMBER < 0x00907000L
  27 RCSID("$OpenBSD: cipher-aes.c,v 1.2 2003/11/26 21:44:29 djm Exp $");
  28
  29 #include <openssl/evp.h>
  30 #include "rijndael.h"
  31 #include "xmalloc.h"
  32 #include "log.h"
  33
  34 #if OPENSSL_VERSION_NUMBER < 0x00906000L
  35 #define SSH_OLD_EVP
  36 #endif
  37
  38 #define RIJNDAEL_BLOCKSIZE 16
  39 struct ssh_rijndael_ctx
  40 {
  41         rijndael_ctx    r_ctx;
  42         u_char          r_iv[RIJNDAEL_BLOCKSIZE];
  43 };
  44
  45 const EVP_CIPHER * evp_rijndael(void);
  46 void ssh_rijndael_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
  47
  48 static int
  49 ssh_rijndael_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
  50     int enc)
  51 {
  52         struct ssh_rijndael_ctx *c;
  53
  54         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
  55                 c = xmalloc(sizeof(*c));
  56                 EVP_CIPHER_CTX_set_app_data(ctx, c);
  57         }
  58         if (key != NULL) {
  59                 if (enc == -1)
  60                         enc = ctx->encrypt;
  61                 rijndael_set_key(&c->r_ctx, (u_char *)key,
  62                     8*EVP_CIPHER_CTX_key_length(ctx), enc);
  63         }
  64         if (iv != NULL)
  65                 memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
  66         return (1);
  67 }
  68
  69 static int
  70 ssh_rijndael_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src,
  71     u_int len)
  72 {
  73         struct ssh_rijndael_ctx *c;
  74         u_char buf[RIJNDAEL_BLOCKSIZE];
  75         u_char *cprev, *cnow, *plain, *ivp;
  76         int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
  77
  78         if (len == 0)
  79                 return (1);
  80         if (len % RIJNDAEL_BLOCKSIZE)
  81                 fatal("ssh_rijndael_cbc: bad len %d", len);
  82         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
  83                 error("ssh_rijndael_cbc: no context");
  84                 return (0);
  85         }
  86         if (ctx->encrypt) {
  87                 cnow  = dest;
  88                 plain = (u_char *)src;
  89                 cprev = c->r_iv;
  90                 for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
  91                     cnow+=RIJNDAEL_BLOCKSIZE) {
  92                         for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
  93                                 buf[j] = plain[j] ^ cprev[j];
  94                         rijndael_encrypt(&c->r_ctx, buf, cnow);
  95                         cprev = cnow;
  96                 }
  97                 memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
  98         } else {
  99                 cnow  = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
 100                 plain = dest+len-RIJNDAEL_BLOCKSIZE;
 101
 102                 memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
 103                 for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
 104                     plain-=RIJNDAEL_BLOCKSIZE) {
 105                         rijndael_decrypt(&c->r_ctx, cnow, plain);
 106                         ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
 107                         for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
 108                                 plain[j] ^= ivp[j];
 109                 }
 110                 memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
 111         }
 112         return (1);
 113 }
 114
 115 static int
 116 ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
 117 {
 118         struct ssh_rijndael_ctx *c;
 119
 120         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
 121                 memset(c, 0, sizeof(*c));
 122                 xfree(c);
 123                 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
 124         }
 125         return (1);
 126 }
 127
 128 void
 129 ssh_rijndael_iv(EVP_CIPHER_CTX *evp, int doset, u_char * iv, u_int len)
 130 {
 131         struct ssh_rijndael_ctx *c;
 132
 133         if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
 134                 fatal("ssh_rijndael_iv: no context");
 135         if (doset)
 136                 memcpy(c->r_iv, iv, len);
 137         else
 138                 memcpy(iv, c->r_iv, len);
 139 }
 140
 141 const EVP_CIPHER *
 142 evp_rijndael(void)
 143 {
 144         static EVP_CIPHER rijndal_cbc;
 145
 146         memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
 147         rijndal_cbc.nid = NID_undef;
 148         rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
 149         rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
 150         rijndal_cbc.key_len = 16;
 151         rijndal_cbc.init = ssh_rijndael_init;
 152         rijndal_cbc.cleanup = ssh_rijndael_cleanup;
 153         rijndal_cbc.do_cipher = ssh_rijndael_cbc;
 154 #ifndef SSH_OLD_EVP
 155         rijndal_cbc.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH |
 156             EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
 157 #endif
 158         return (&rijndal_cbc);
 159 }
 160 #endif /* OPENSSL_VERSION_NUMBER */