contrib/cryptsetup/lib/backends.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdlib.h>
   4 #include <errno.h>
   5 #include <openssl/evp.h>
   6
   7 #include "libcryptsetup.h"
   8 #include "internal.h"
   9
  10 int init_crypto(void)
  11 {
  12         return 0;
  13 }
  14
  15 int hash(const char *backend_name, const char *hash_name,
  16          char *result, size_t size,
  17          const char *passphrase, size_t sizep)
  18 {
  19         EVP_MD_CTX mdctx;
  20         const EVP_MD *md;
  21         size_t pad = 0;
  22         int r = -ENOENT;
  23
  24         OpenSSL_add_all_digests();
  25         md = EVP_get_digestbyname(hash_name);
  26         if (md == NULL) {
  27                 set_error("Unknown hash type %s", hash_name);
  28                 goto out;
  29         }
  30
  31         if (EVP_MD_size(md) > size) {
  32                 set_error("requested hash length (%zd) > key length (%zd)", EVP_MD_size(md), size);
  33                 return -EINVAL;
  34         }
  35
  36         pad = size - EVP_MD_size(md);
  37
  38         EVP_DigestInit(&mdctx, md);
  39         EVP_DigestUpdate(&mdctx, passphrase, sizep);
  40         r = !EVP_DigestFinal(&mdctx, result, NULL);
  41
  42         if (pad) {
  43                 memset(result+size, 0, pad);
  44         }
  45
  46 out:
  47         return r;
  48 }
  49