sqlcipher/src/crypto_libtomcrypt.c

#ifdef SQLCIPHER_CRYPTO_LIBTOMCRYPT
#include "sqliteInt.h"
#include "sqlcipher.h"
#include <tomcrypt.h>

typedef struct {
  prng_state prng;
} ltc_ctx;

static unsigned int ltc_init = 0;

static int sqlcipher_ltc_add_random(void *ctx, void *buffer, int length) {
  ltc_ctx *ltc = (ltc_ctx*)ctx;
  int rc = fortuna_add_entropy(buffer, length, &(ltc->prng));
  return rc != CRYPT_OK ? SQLITE_ERROR : SQLITE_OK;
}

static int sqlcipher_ltc_activate(void *ctx) {
  ltc_ctx *ltc = (ltc_ctx*)ctx;
  sqlite3_mutex_enter(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
  if(ltc_init == 0) {
    if(register_prng(&fortuna_desc) != CRYPT_OK) return SQLITE_ERROR;
    if(register_cipher(&rijndael_desc) != CRYPT_OK) return SQLITE_ERROR;
    if(register_hash(&sha1_desc) != CRYPT_OK) return SQLITE_ERROR;
    if(fortuna_start(&(ltc->prng)) != CRYPT_OK) return SQLITE_ERROR;
    if(sqlcipher_ltc_add_random(ctx, &ltc, sizeof(ltc_ctx *)) != SQLITE_OK) return SQLITE_ERROR;
    ltc_init = 1;
  }
  sqlite3_mutex_leave(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER));
  return SQLITE_OK;
}

static int sqlcipher_ltc_deactivate(void *ctx) {
  ltc_ctx *ltc = (ltc_ctx*)ctx;
  fortuna_done(&(ltc->prng));
}

static const char* sqlcipher_ltc_get_provider_name(void *ctx) {
  return "libtomcrypt";
}

static int sqlcipher_ltc_random(void *ctx, void *buffer, int length) {
  ltc_ctx *ltc = (ltc_ctx*)ctx;
  int random_buffer_sz = 256;
  char random_buffer[random_buffer_sz];
  
  sqlite3_randomness(random_buffer_sz, &random_buffer);
  if(sqlcipher_ltc_add_random(ctx, random_buffer, random_buffer_sz) != SQLITE_OK) {
    return SQLITE_ERROR;
  }
  if(fortuna_ready(&(ltc->prng)) != CRYPT_OK) {
    return SQLITE_ERROR;
  }
  fortuna_read(buffer, length, &(ltc->prng));
  return SQLITE_OK;
}

static int sqlcipher_ltc_hmac(void *ctx, unsigned char *hmac_key, int key_sz, unsigned char *in, int in_sz, unsigned char *in2, int in2_sz, unsigned char *out) {
  int rc, hash_idx;
  hmac_state hmac;
  unsigned long outlen = key_sz;

  hash_idx = find_hash("sha1");
  if((rc = hmac_init(&hmac, hash_idx, hmac_key, key_sz)) != CRYPT_OK) return SQLITE_ERROR;
  if((rc = hmac_process(&hmac, in, in_sz)) != CRYPT_OK) return SQLITE_ERROR;
  if((rc = hmac_process(&hmac, in2, in2_sz)) != CRYPT_OK) return SQLITE_ERROR;
  if((rc = hmac_done(&hmac, out, &outlen)) != CRYPT_OK) return SQLITE_ERROR;
  sqlcipher_ltc_add_random(ctx, out, outlen);
  return SQLITE_OK;
}

static int sqlcipher_ltc_kdf(void *ctx, const unsigned char *pass, int pass_sz, unsigned char* salt, int salt_sz, int workfactor, int key_sz, unsigned char *key) {
  int rc, hash_idx;
  unsigned long outlen = key_sz;
  unsigned long random_buffer_sz = 256;
  char random_buffer[random_buffer_sz];

  hash_idx = find_hash("sha1");
  if((rc = pkcs_5_alg2(pass, pass_sz, salt, salt_sz,
                       workfactor, hash_idx, key, &outlen)) != CRYPT_OK) {
    return SQLITE_ERROR;
  }
  if((rc = pkcs_5_alg2(key, key_sz, salt, salt_sz,
                       1, hash_idx, random_buffer, &random_buffer_sz)) != CRYPT_OK) {
    return SQLITE_ERROR;
  }
  sqlcipher_ltc_add_random(ctx, random_buffer, random_buffer_sz);
  return SQLITE_OK;
}

static const char* sqlcipher_ltc_get_cipher(void *ctx) {
  return "rijndael";
}

static int sqlcipher_ltc_cipher(void *ctx, int mode, unsigned char *key, int key_sz, unsigned char *iv, unsigned char *in, int in_sz, unsigned char *out) {
  int rc, cipher_idx, hash_idx;
  symmetric_CBC cbc;

  if((cipher_idx = find_cipher(sqlcipher_ltc_get_cipher(ctx))) == -1) return SQLITE_ERROR;
  if((rc = cbc_start(cipher_idx, iv, key, key_sz, 0, &cbc)) != CRYPT_OK) return SQLITE_ERROR;
  rc = mode == 1 ? cbc_encrypt(in, out, in_sz, &cbc) : cbc_decrypt(in, out, in_sz, &cbc);
  if(rc != CRYPT_OK) return SQLITE_ERROR;
  cbc_done(&cbc);
  return SQLITE_OK;
}

static int sqlcipher_ltc_set_cipher(void *ctx, const char *cipher_name) {
  return SQLITE_OK;
}

static int sqlcipher_ltc_get_key_sz(void *ctx) {
  int cipher_idx = find_cipher(sqlcipher_ltc_get_cipher(ctx));
  return cipher_descriptor[cipher_idx].max_key_length;
}

static int sqlcipher_ltc_get_iv_sz(void *ctx) {
  int cipher_idx = find_cipher(sqlcipher_ltc_get_cipher(ctx));
  return cipher_descriptor[cipher_idx].block_length;
}

static int sqlcipher_ltc_get_block_sz(void *ctx) {
  int cipher_idx = find_cipher(sqlcipher_ltc_get_cipher(ctx));
  return cipher_descriptor[cipher_idx].block_length;
}

static int sqlcipher_ltc_get_hmac_sz(void *ctx) {
  int hash_idx = find_hash("sha1");
  return hash_descriptor[hash_idx].hashsize;
}

static int sqlcipher_ltc_ctx_copy(void *target_ctx, void *source_ctx) {
  return 1;
}

static int sqlcipher_ltc_ctx_cmp(void *c1, void *c2) {
  return 1;
}

static int sqlcipher_ltc_ctx_init(void **ctx) {
  *ctx = sqlcipher_malloc(sizeof(ltc_ctx));
  if(*ctx == NULL) return SQLITE_NOMEM;
  sqlcipher_ltc_activate(*ctx);
  return SQLITE_OK;
}

static int sqlcipher_ltc_ctx_free(void **ctx) {
  sqlcipher_ltc_deactivate(&ctx);
  sqlcipher_free(*ctx, sizeof(ltc_ctx));
  return SQLITE_OK;
}

int sqlcipher_ltc_setup(sqlcipher_provider *p) {
  p->activate = sqlcipher_ltc_activate;  
  p->deactivate = sqlcipher_ltc_deactivate;
  p->get_provider_name = sqlcipher_ltc_get_provider_name;
  p->random = sqlcipher_ltc_random;
  p->hmac = sqlcipher_ltc_hmac;
  p->kdf = sqlcipher_ltc_kdf;
  p->cipher = sqlcipher_ltc_cipher;
  p->set_cipher = sqlcipher_ltc_set_cipher;
  p->get_cipher = sqlcipher_ltc_get_cipher;
  p->get_key_sz = sqlcipher_ltc_get_key_sz;
  p->get_iv_sz = sqlcipher_ltc_get_iv_sz;
  p->get_block_sz = sqlcipher_ltc_get_block_sz;
  p->get_hmac_sz = sqlcipher_ltc_get_hmac_sz;
  p->ctx_copy = sqlcipher_ltc_ctx_copy;
  p->ctx_cmp = sqlcipher_ltc_ctx_cmp;
  p->ctx_init = sqlcipher_ltc_ctx_init;
  p->ctx_free = sqlcipher_ltc_ctx_free;
  p->add_random = sqlcipher_ltc_add_random;
}


#endif