lib/hcrypto/example_evp_cipher.c

   1 /*
   2  * Copyright (c) 2008 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <krb5-types.h> /* should really be stdint.h */
  35 #include <hcrypto/evp.h>
  36
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <err.h>
  41 #include <assert.h>
  42
  43 #include "roken.h"
  44
  45 /* key and initial vector */
  46 static char key[16] =
  47     "\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"
  48     "\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4";
  49 static char ivec[16] =
  50     "\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"
  51     "\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4";
  52
  53 static void
  54 usage(int exit_code) __attribute__((noreturn));
  55
  56 static void
  57 usage(int exit_code)
  58 {
  59     printf("usage: %s in out\n", getprogname());
  60     exit(exit_code);
  61 }
  62
  63
  64 int
  65 main(int argc, char **argv)
  66 {
  67     int encryptp = 1;
  68     const char *ifn = NULL, *ofn = NULL;
  69     FILE *in, *out;
  70     void *ibuf, *obuf;
  71     int ilen, olen;
  72     size_t block_size = 0;
  73     const EVP_CIPHER *c = EVP_aes_128_cbc();
  74     EVP_CIPHER_CTX ctx;
  75     int ret;
  76
  77     setprogname(argv[0]);
  78
  79     if (argc == 2) {
  80         if (strcmp(argv[1], "--version") == 0) {
  81             printf("version");
  82             exit(0);
  83         }
  84         if (strcmp(argv[1], "--help") == 0)
  85             usage(0);
  86         usage(1);
  87     } else if (argc == 4) {
  88         block_size = atoi(argv[1]);
  89         if (block_size == 0)
  90             errx(1, "invalid blocksize %s", argv[1]);
  91         ifn = argv[2];
  92         ofn = argv[3];
  93     } else
  94         usage(1);
  95
  96     in = fopen(ifn, "r");
  97     if (in == NULL)
  98         errx(1, "failed to open input file");
  99     out = fopen(ofn, "w+");
 100     if (out == NULL)
 101         errx(1, "failed to open output file");
 102
 103     /* Check that key and ivec are long enough */
 104     assert(EVP_CIPHER_key_length(c) <= sizeof(key));
 105     assert(EVP_CIPHER_iv_length(c) <= sizeof(ivec));
 106
 107     /*
 108      * Allocate buffer, the output buffer is at least
 109      * EVP_CIPHER_block_size() longer
 110      */
 111     ibuf = malloc(block_size);
 112     obuf = malloc(block_size + EVP_CIPHER_block_size(c));
 113
 114     /*
 115      * Init the memory used for EVP_CIPHER_CTX and set the key and
 116      * ivec.
 117      */
 118     EVP_CIPHER_CTX_init(&ctx);
 119     EVP_CipherInit_ex(&ctx, c, NULL, key, ivec, encryptp);
 120
 121     /* read in buffer */
 122     while ((ilen = fread(ibuf, 1, block_size, in)) > 0) {
 123         /* encrypto/decrypt */
 124         ret = EVP_CipherUpdate(&ctx, obuf, &olen, ibuf, ilen);
 125         if (ret != 1) {
 126             EVP_CIPHER_CTX_cleanup(&ctx);
 127             errx(1, "EVP_CipherUpdate failed");
 128         }
 129         /* write out to output file */
 130         fwrite(obuf, 1, olen, out);
 131     }
 132     /* done reading */
 133     fclose(in);
 134
 135     /* clear up any last bytes left in the output buffer */
 136     ret = EVP_CipherFinal_ex(&ctx, obuf, &olen);
 137     EVP_CIPHER_CTX_cleanup(&ctx);
 138     if (ret != 1)
 139         errx(1, "EVP_CipherFinal_ex failed");
 140
 141     /* write the last bytes out and close */
 142     fwrite(obuf, 1, olen, out);
 143     fclose(out);
 144
 145     return 0;
 146 }