src/crypto.h

   1 /*
   2 ** SQLCipher
   3 ** crypto.h developed by Stephen Lombardo (Zetetic LLC)
   4 ** sjlombardo at zetetic dot net
   5 ** http://zetetic.net
   6 **
   7 ** Copyright (c) 2008, ZETETIC LLC
   8 ** All rights reserved.
   9 **
  10 ** Redistribution and use in source and binary forms, with or without
  11 ** modification, are permitted provided that the following conditions are met:
  12 **     * Redistributions of source code must retain the above copyright
  13 **       notice, this list of conditions and the following disclaimer.
  14 **     * Redistributions in binary form must reproduce the above copyright
  15 **       notice, this list of conditions and the following disclaimer in the
  16 **       documentation and/or other materials provided with the distribution.
  17 **     * Neither the name of the ZETETIC LLC nor the
  18 **       names of its contributors may be used to endorse or promote products
  19 **       derived from this software without specific prior written permission.
  20 **
  21 ** THIS SOFTWARE IS PROVIDED BY ZETETIC LLC ''AS IS'' AND ANY
  22 ** EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  23 ** WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24 ** DISCLAIMED. IN NO EVENT SHALL ZETETIC LLC BE LIABLE FOR ANY
  25 ** DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  26 ** (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  27 ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  28 ** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  30 ** SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31 **
  32 */
  33 /* BEGIN CRYPTO */
  34 #ifdef SQLITE_HAS_CODEC
  35 #ifndef CRYPTO_H
  36 #define CRYPTO_H
  37
  38 #define FILE_HEADER_SZ 16
  39
  40 #ifndef CIPHER
  41 #define CIPHER "aes-256-cbc"
  42 #endif
  43
  44 #define CIPHER_DECRYPT 0
  45 #define CIPHER_ENCRYPT 1
  46
  47 #define CIPHER_READ_CTX 0
  48 #define CIPHER_WRITE_CTX 1
  49 #define CIPHER_READWRITE_CTX 2
  50
  51 #ifndef PBKDF2_ITER
  52 #define PBKDF2_ITER 4000
  53 #endif
  54
  55 #ifndef DEFAULT_USE_HMAC
  56 #define DEFAULT_USE_HMAC 1
  57 #endif
  58
  59 /* by default, sqlcipher will use a reduced number of iterations to generate
  60    the HMAC key / or transform a raw cipher key
  61    */
  62 #ifndef FAST_PBKDF2_ITER
  63 #define FAST_PBKDF2_ITER 2
  64 #endif
  65
  66 /* this if a fixed random array that will be xor'd with the database salt to ensure that the
  67    salt passed to the HMAC key derivation function is not the same as that used to derive
  68    the encryption key. This can be overridden at compile time but it will make the resulting
  69    binary incompatible with the default builds when using HMAC. A future version of SQLcipher
  70    will likely allow this to be defined at runtime via pragma */
  71 #ifndef HMAC_SALT_MASK
  72 #define HMAC_SALT_MASK 0x3a
  73 #endif
  74
  75 #ifdef CODEC_DEBUG
  76 #define CODEC_TRACE(X)  {printf X;fflush(stdout);}
  77 #else
  78 #define CODEC_TRACE(X)
  79 #endif
  80
  81
  82 /* extensions defined in pragma.c */
  83
  84 void sqlite3pager_get_codec(Pager *pPager, void **ctx);
  85 int sqlite3pager_is_mj_pgno(Pager *pPager, Pgno pgno);
  86 sqlite3_file *sqlite3Pager_get_fd(Pager *pPager);
  87 void sqlite3pager_sqlite3PagerSetCodec(
  88   Pager *pPager,
  89   void *(*xCodec)(void*,void*,Pgno,int),
  90   void (*xCodecSizeChng)(void*,int,int),
  91   void (*xCodecFree)(void*),
  92   void *pCodec
  93 );
  94 /* end extensions defined in pragma.c */
  95
  96 /*
  97 **  Simple shared routines for converting hex char strings to binary data
  98  */
  99 static int cipher_hex2int(char c) {
 100   return (c>='0' && c<='9') ? (c)-'0' :
 101          (c>='A' && c<='F') ? (c)-'A'+10 :
 102          (c>='a' && c<='f') ? (c)-'a'+10 : 0;
 103 }
 104
 105 static void cipher_hex2bin(const char *hex, int sz, unsigned char *out){
 106   int i;
 107   for(i = 0; i < sz; i += 2){
 108     out[i/2] = (cipher_hex2int(hex[i])<<4) | cipher_hex2int(hex[i+1]);
 109   }
 110 }
 111
 112 /* extensions defined in crypto_impl.c */
 113
 114 typedef struct codec_ctx codec_ctx;
 115
 116 /* utility functions */
 117 int sqlcipher_memcmp(const unsigned char *a0, const unsigned char *a1, int len);
 118 int sqlcipher_pseudorandom(void *, int);
 119 void sqlcipher_free(void *, int);
 120
 121 /* activation and initialization */
 122 void sqlcipher_activate();
 123 int sqlcipher_codec_ctx_init(codec_ctx **, Db *, Pager *, sqlite3_file *, const void *, int);
 124 void sqlcipher_codec_ctx_free(codec_ctx **);
 125 int sqlcipher_codec_key_derive(codec_ctx *);
 126 int sqlcipher_codec_key_copy(codec_ctx *, int);
 127
 128 /* page cipher implementation */
 129 int sqlcipher_page_cipher(codec_ctx *, int, Pgno, int, int, unsigned char *, unsigned char *);
 130
 131 /* context setters & getters */
 132 void sqlcipher_codec_ctx_set_error(codec_ctx *, int);
 133
 134 int sqlcipher_codec_ctx_set_pass(codec_ctx *, const void *, int, int);
 135 void sqlcipher_codec_get_pass(codec_ctx *, void **zKey, int *nKey);
 136
 137 int sqlcipher_codec_ctx_set_pagesize(codec_ctx *, int);
 138 int sqlcipher_codec_ctx_get_pagesize(codec_ctx *);
 139 int sqlcipher_codec_ctx_get_reservesize(codec_ctx *);
 140
 141 int sqlcipher_codec_ctx_set_kdf_iter(codec_ctx *, int, int);
 142 void* sqlcipher_codec_ctx_get_kdf_salt(codec_ctx *ctx);
 143
 144 int sqlcipher_codec_ctx_set_fast_kdf_iter(codec_ctx *, int, int);
 145
 146 int sqlcipher_codec_ctx_set_cipher(codec_ctx *, const char *, int);
 147
 148 void* sqlcipher_codec_ctx_get_data(codec_ctx *);
 149
 150 void sqlcipher_exportFunc(sqlite3_context *, int, sqlite3_value **);
 151
 152 void sqlcipher_set_default_use_hmac(int use);
 153
 154 int sqlcipher_codec_ctx_set_use_hmac(codec_ctx *ctx, int use);
 155 /* end extensions defined in crypto_impl.c */
 156
 157 #endif
 158 #endif
 159 /* END CRYPTO */