lib/hcrypto/pkcs12.c

   1 /*
   2  * Copyright (c) 2006 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 <config.h>
  35 #include <roken.h>
  36 #include <assert.h>
  37
  38 #include <pkcs12.h>
  39 #include <bn.h>
  40
  41 int
  42 PKCS12_key_gen(const void *key, size_t keylen,
  43                const void *salt, size_t saltlen,
  44                int id, int iteration, size_t outkeysize,
  45                void *out, const EVP_MD *md)
  46 {
  47     unsigned char *v, *I, hash[EVP_MAX_MD_SIZE];
  48     unsigned int size, size_I = 0;
  49     unsigned char idc = id;
  50     EVP_MD_CTX *ctx;
  51     unsigned char *outp = out;
  52     int i, vlen;
  53
  54     /**
  55      * The argument key is pointing to an utf16 string, and thus
  56      * keylen that is no a multiple of 2 is invalid.
  57      */
  58     if (keylen & 1)
  59         return 0;
  60
  61     ctx = EVP_MD_CTX_create();
  62     if (ctx == NULL)
  63         return 0;
  64
  65     vlen = EVP_MD_block_size(md);
  66     v = malloc(vlen + 1);
  67     if (v == NULL) {
  68         EVP_MD_CTX_destroy(ctx);
  69         return 0;
  70     }
  71
  72     I = calloc(1, vlen * 2);
  73     if (I == NULL) {
  74         EVP_MD_CTX_destroy(ctx);
  75         free(v);
  76         return 0;
  77     }
  78
  79     if (salt && saltlen > 0) {
  80         for (i = 0; i < vlen; i++)
  81             I[i] = ((unsigned char*)salt)[i % saltlen];
  82         size_I += vlen;
  83     }
  84     /*
  85      * There is a diffrence between the no password string and the
  86      * empty string, in the empty string the UTF16 NUL terminator is
  87      * included into the string.
  88      */
  89     if (key) {
  90         for (i = 0; i < vlen / 2; i++) {
  91             I[(i * 2) + size_I] = 0;
  92             I[(i * 2) + size_I + 1] = ((unsigned char*)key)[i % (keylen + 1)];
  93         }
  94         size_I += vlen;
  95     }
  96
  97     while (1) {
  98         BIGNUM *bnB, *bnOne;
  99
 100         if (!EVP_DigestInit_ex(ctx, md, NULL)) {
 101             EVP_MD_CTX_destroy(ctx);
 102             free(I);
 103             free(v);
 104             return 0;
 105         }
 106         for (i = 0; i < vlen; i++)
 107             EVP_DigestUpdate(ctx, &idc, 1);
 108         EVP_DigestUpdate(ctx, I, size_I);
 109         EVP_DigestFinal_ex(ctx, hash, &size);
 110
 111         for (i = 1; i < iteration; i++)
 112             EVP_Digest(hash, size, hash, &size, md, NULL);
 113
 114         memcpy(outp, hash, min(outkeysize, size));
 115         if (outkeysize < size)
 116             break;
 117         outkeysize -= size;
 118         outp += size;
 119
 120         for (i = 0; i < vlen; i++)
 121             v[i] = hash[i % size];
 122
 123         bnB = BN_bin2bn(v, vlen, NULL);
 124         bnOne = BN_new();
 125         BN_set_word(bnOne, 1);
 126
 127         BN_uadd(bnB, bnB, bnOne);
 128
 129         for (i = 0; i < vlen * 2; i += vlen) {
 130             BIGNUM *bnI;
 131             int j;
 132
 133             bnI = BN_bin2bn(I + i, vlen, NULL);
 134
 135             BN_uadd(bnI, bnI, bnB);
 136
 137             j = BN_num_bytes(bnI);
 138             if (j > vlen) {
 139                 assert(j == vlen + 1);
 140                 BN_bn2bin(bnI, v);
 141                 memcpy(I + i, v + 1, vlen);
 142             } else {
 143                 memset(I + i, 0, vlen - j);
 144                 BN_bn2bin(bnI, I + i + vlen - j);
 145             }
 146             BN_free(bnI);
 147         }
 148         BN_free(bnB);
 149         BN_free(bnOne);
 150         size_I = vlen * 2;
 151     }
 152
 153     EVP_MD_CTX_destroy(ctx);
 154     free(I);
 155     free(v);
 156
 157     return 1;
 158 }