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
  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 const EVP_CIPHER * evp_rijndael(void);
  50 void ssh_rijndael_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);
  51
  52 static int
  53 ssh_rijndael_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
  54     int enc)
  55 {
  56         struct ssh_rijndael_ctx *c;
  57
  58         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
  59                 c = xmalloc(sizeof(*c));
  60                 EVP_CIPHER_CTX_set_app_data(ctx, c);
  61         }
  62         if (key != NULL) {
  63                 if (enc == -1)
  64                         enc = ctx->encrypt;
  65                 rijndael_set_key(&c->r_ctx, (u_char *)key,
  66                     8*EVP_CIPHER_CTX_key_length(ctx), enc);
  67         }
  68         if (iv != NULL)
  69                 memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
  70         return (1);
  71 }
  72
  73 static int
  74 ssh_rijndael_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src,
  75     u_int len)
  76 {
  77         struct ssh_rijndael_ctx *c;
  78         u_char buf[RIJNDAEL_BLOCKSIZE];
  79         u_char *cprev, *cnow, *plain, *ivp;
  80         int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
  81
  82         if (len == 0)
  83                 return (1);
  84         if (len % RIJNDAEL_BLOCKSIZE)
  85                 fatal("ssh_rijndael_cbc: bad len %d", len);
  86         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
  87                 error("ssh_rijndael_cbc: no context");
  88                 return (0);
  89         }
  90         if (ctx->encrypt) {
  91                 cnow  = dest;
  92                 plain = (u_char *)src;
  93                 cprev = c->r_iv;
  94                 for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
  95                     cnow+=RIJNDAEL_BLOCKSIZE) {
  96                         for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
  97                                 buf[j] = plain[j] ^ cprev[j];
  98                         rijndael_encrypt(&c->r_ctx, buf, cnow);
  99                         cprev = cnow;
 100                 }
 101                 memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
 102         } else {
 103                 cnow  = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
 104                 plain = dest+len-RIJNDAEL_BLOCKSIZE;
 105
 106                 memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
 107                 for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
 108                     plain-=RIJNDAEL_BLOCKSIZE) {
 109                         rijndael_decrypt(&c->r_ctx, cnow, plain);
 110                         ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
 111                         for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
 112                                 plain[j] ^= ivp[j];
 113                 }
 114                 memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
 115         }
 116         return (1);
 117 }
 118
 119 static int
 120 ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
 121 {
 122         struct ssh_rijndael_ctx *c;
 123
 124         if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
 125                 memset(c, 0, sizeof(*c));
 126                 xfree(c);
 127                 EVP_CIPHER_CTX_set_app_data(ctx, NULL);
 128         }
 129         return (1);
 130 }
 131
 132 void
 133 ssh_rijndael_iv(EVP_CIPHER_CTX *evp, int doset, u_char * iv, u_int len)
 134 {
 135         struct ssh_rijndael_ctx *c;
 136
 137         if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL)
 138                 fatal("ssh_rijndael_iv: no context");
 139         if (doset)
 140                 memcpy(c->r_iv, iv, len);
 141         else
 142                 memcpy(iv, c->r_iv, len);
 143 }
 144
 145 const EVP_CIPHER *
 146 evp_rijndael(void)
 147 {
 148         static EVP_CIPHER rijndal_cbc;
 149
 150         memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
 151         rijndal_cbc.nid = NID_undef;
 152         rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
 153         rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
 154         rijndal_cbc.key_len = 16;
 155         rijndal_cbc.init = ssh_rijndael_init;
 156         rijndal_cbc.cleanup = ssh_rijndael_cleanup;
 157         rijndal_cbc.do_cipher = ssh_rijndael_cbc;
 158 #ifndef SSH_OLD_EVP
 159         rijndal_cbc.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH |
 160             EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
 161 #endif
 162         return (&rijndal_cbc);
 163 }
 164 #endif /* USE_BUILTIN_RIJNDAEL */