src/common/pkcs5_pbkdf2.c

   1 /* pkcs5_pbkdf2.c - Password-Based Key Derivation Function 2
   2  * Copyright (c) 2008 Damien Bergamini <damien.bergamini@free.fr>
   3  *
   4  * Modifications for Claws Mail are:
   5  * Copyright (c) 2016 the Claws Mail team
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include "config.h"
  21
  22 #include <glib.h>
  23 #include <sys/types.h>
  24
  25 #include <string.h>
  26 #include <stdint.h>
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29
  30 #define CHECKSUM_BLOCKLEN 64
  31 #define SHA1_DIGESTLEN 20
  32
  33 /*
  34  * HMAC-SHA-1 (from RFC 2202).
  35  */
  36 static void
  37 hmac_sha1(const guchar *text, size_t text_len, const guchar *key,
  38     size_t key_len, guchar *digest)
  39 {
  40         GChecksum *cksum;
  41         gsize outlen;
  42         guchar k_pad[CHECKSUM_BLOCKLEN];
  43         guchar tk[SHA1_DIGESTLEN];
  44         gint i;
  45
  46         if (key_len > CHECKSUM_BLOCKLEN) {
  47                 cksum = g_checksum_new(G_CHECKSUM_SHA1);
  48                 g_checksum_update(cksum, key, key_len);
  49                 outlen = SHA1_DIGESTLEN;
  50                 g_checksum_get_digest(cksum, tk, &outlen);
  51                 g_checksum_free(cksum);
  52
  53                 key = tk;
  54                 key_len = SHA1_DIGESTLEN;
  55         }
  56
  57         memset(k_pad, 0, sizeof k_pad);
  58         memcpy(k_pad, key, key_len);
  59         for (i = 0; i < CHECKSUM_BLOCKLEN; i++)
  60                 k_pad[i] ^= 0x36;
  61
  62         cksum = g_checksum_new(G_CHECKSUM_SHA1);
  63         g_checksum_update(cksum, k_pad, CHECKSUM_BLOCKLEN);
  64         g_checksum_update(cksum, text, text_len);
  65         outlen = SHA1_DIGESTLEN;
  66         g_checksum_get_digest(cksum, digest, &outlen);
  67         g_checksum_free(cksum);
  68
  69         memset(k_pad, 0, sizeof k_pad);
  70         memcpy(k_pad, key, key_len);
  71         for (i = 0; i < CHECKSUM_BLOCKLEN; i++)
  72                 k_pad[i] ^= 0x5c;
  73
  74         cksum = g_checksum_new(G_CHECKSUM_SHA1);
  75         g_checksum_update(cksum, k_pad, CHECKSUM_BLOCKLEN);
  76         g_checksum_update(cksum, digest, SHA1_DIGESTLEN);
  77         outlen = SHA1_DIGESTLEN;
  78         g_checksum_get_digest(cksum, digest, &outlen);
  79         g_checksum_free(cksum);
  80 }
  81
  82 #undef CHECKSUM_BLOCKLEN
  83
  84 /*
  85  * Password-Based Key Derivation Function 2 (PKCS #5 v2.0).
  86  * Code based on IEEE Std 802.11-2007, Annex H.4.2.
  87  */
  88 gint
  89 pkcs5_pbkdf2(const gchar *pass, size_t pass_len, const guchar *salt,
  90     size_t salt_len, guchar *key, size_t key_len, guint rounds)
  91 {
  92         guchar *asalt, obuf[SHA1_DIGESTLEN];
  93         guchar d1[SHA1_DIGESTLEN], d2[SHA1_DIGESTLEN];
  94         guint i, j;
  95         guint count;
  96         size_t r;
  97
  98         if (pass == NULL || salt == NULL || key == NULL)
  99                 return -1;
 100         if (rounds < 1 || key_len == 0)
 101                 return -1;
 102         if (salt_len == 0 || salt_len > SIZE_MAX - 4)
 103                 return -1;
 104         if ((asalt = malloc(salt_len + 4)) == NULL)
 105                 return -1;
 106
 107         memcpy(asalt, salt, salt_len);
 108
 109         for (count = 1; key_len > 0; count++) {
 110                 asalt[salt_len + 0] = (count >> 24) & 0xff;
 111                 asalt[salt_len + 1] = (count >> 16) & 0xff;
 112                 asalt[salt_len + 2] = (count >> 8) & 0xff;
 113                 asalt[salt_len + 3] = count & 0xff;
 114                 hmac_sha1(asalt, salt_len + 4, pass, pass_len, d1);
 115                 memcpy(obuf, d1, sizeof(obuf));
 116
 117                 for (i = 1; i < rounds; i++) {
 118                         hmac_sha1(d1, sizeof(d1), pass, pass_len, d2);
 119                         memcpy(d1, d2, sizeof(d1));
 120                         for (j = 0; j < sizeof(obuf); j++)
 121                                 obuf[j] ^= d1[j];
 122                 }
 123
 124                 r = MIN(key_len, SHA1_DIGESTLEN);
 125                 memcpy(key, obuf, r);
 126                 key += r;
 127                 key_len -= r;
 128         };
 129         memset(asalt, 0, salt_len + 4);
 130         free(asalt);
 131         memset(d1, 0, sizeof(d1));
 132         memset(d2, 0, sizeof(d2));
 133         memset(obuf, 0, sizeof(obuf));
 134
 135         return 0;
 136 }
 137
 138 #undef SHA1_DIGESTLEN