example-cipher.c

   1 /*
   2  * Demo on how to use OpenBSD /dev/crypto device.
   3  *
   4  * Author: Michal Ludvig <michal@logix.cz>
   5  *         http://www.logix.cz/michal
   6  *
   7  * Note: by default OpenBSD doesn't allow using
   8  *       /dev/crypto if there is no hardware accelerator
   9  *       for a given algorithm. To change this you'll have to
  10  *       set cryptodevallowsoft=1 in
  11  *       /usr/src/sys/crypto/cryptodev.c and rebuild your kernel.
  12  */
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <fcntl.h>
  17
  18 #include <sys/ioctl.h>
  19 //#include <crypto/cryptodev.h>
  20 #include "cryptodev.h"
  21
  22 #define DATA_SIZE       4096
  23 #define BLOCK_SIZE      16
  24 #define KEY_SIZE        16
  25
  26 static int
  27 test_crypto(int cfd)
  28 {
  29         struct {
  30                 char    in[DATA_SIZE],
  31                         encrypted[DATA_SIZE],
  32                         decrypted[DATA_SIZE],
  33                         iv[BLOCK_SIZE],
  34                         key[KEY_SIZE];
  35         } data;
  36         struct session_op sess;
  37         struct crypt_op cryp;
  38
  39         memset(&sess, 0, sizeof(sess));
  40         memset(&cryp, 0, sizeof(cryp));
  41
  42         /* Use the garbage that is on the stack :-) */
  43         /* memset(&data, 0, sizeof(data)); */
  44
  45         /* Get crypto session for AES128 */
  46         sess.cipher = CRYPTO_AES_CBC;
  47         sess.keylen = KEY_SIZE;
  48         sess.key = data.key;
  49         if (ioctl(cfd, CIOCGSESSION, &sess)) {
  50                 perror("ioctl(CIOCGSESSION)");
  51                 return 1;
  52         }
  53
  54         /* Encrypt data.in to data.encrypted */
  55         cryp.ses = sess.ses;
  56         cryp.len = sizeof(data.in);
  57         cryp.src = data.in;
  58         cryp.dst = data.encrypted;
  59         cryp.iv = data.iv;
  60         cryp.op = COP_ENCRYPT;
  61         if (ioctl(cfd, CIOCCRYPT, &cryp)) {
  62                 perror("ioctl(CIOCCRYPT)");
  63                 return 1;
  64         }
  65
  66         /* Decrypt data.encrypted to data.decrypted */
  67         cryp.src = data.encrypted;
  68         cryp.dst = data.decrypted;
  69         cryp.op = COP_DECRYPT;
  70         if (ioctl(cfd, CIOCCRYPT, &cryp)) {
  71                 perror("ioctl(CIOCCRYPT)");
  72                 return 1;
  73         }
  74
  75         /* Verify the result */
  76         if (memcmp(data.in, data.decrypted, sizeof(data.in)) != 0) {
  77                 fprintf(stderr,
  78                         "FAIL: Decrypted data are different from the input data.\n");
  79                 return 1;
  80         } else
  81                 printf("Test passed\n");
  82
  83         /* Finish crypto session */
  84         if (ioctl(cfd, CIOCFSESSION, &sess.ses)) {
  85                 perror("ioctl(CIOCFSESSION)");
  86                 return 1;
  87         }
  88
  89         return 0;
  90 }
  91
  92 int
  93 main()
  94 {
  95         int fd = -1, cfd = -1;
  96
  97         /* Open the crypto device */
  98         fd = open("/dev/crypto", O_RDWR, 0);
  99         if (fd < 0) {
 100                 perror("open(/dev/crypto)");
 101                 return 1;
 102         }
 103
 104         /* Clone file descriptor */
 105         if (ioctl(fd, CRIOGET, &cfd)) {
 106                 perror("ioctl(CRIOGET)");
 107                 return 1;
 108         }
 109
 110         /* Set close-on-exec (not really neede here) */
 111         if (fcntl(cfd, F_SETFD, 1) == -1) {
 112                 perror("fcntl(F_SETFD)");
 113                 return 1;
 114         }
 115
 116         /* Run the test itself */
 117         if (test_crypto(cfd))
 118                 return 1;
 119
 120         /* Close cloned descriptor */
 121         if (close(cfd)) {
 122                 perror("close(cfd)");
 123                 return 1;
 124         }
 125
 126         /* Close the original descriptor */
 127         if (close(fd)) {
 128                 perror("close(fd)");
 129                 return 1;
 130         }
 131
 132         return 0;
 133 }