Esempio n. 1
0
int sqliterkCryptoDecode(sqliterk_codec *codec, int pgno, void *data)
{
    int rc;
    int offset = 0;
    unsigned char *pdata = (unsigned char *) data;

    int page_sz = sqlcipher_codec_ctx_get_pagesize(codec);
    unsigned char *buffer =
        (unsigned char *) sqlcipher_codec_ctx_get_data(codec);

    rc = sqlcipher_codec_key_derive(codec);
    if (rc != SQLITE_OK)
        return rc;

    if (pgno == 1) {
        offset = 16; // FILE_HEADER_SZ
        memcpy(buffer, "SQLite format 3", 16);
    }
    rc = sqlcipher_page_cipher(codec, CIPHER_READ_CTX, pgno, CIPHER_DECRYPT,
                               page_sz - offset, pdata + offset,
                               buffer + offset);
    if (rc != SQLITE_OK)
        goto bail;
    memcpy(pdata, buffer, page_sz);

    return SQLITERK_OK;

bail:
    sqliterkOSError(SQLITERK_DAMAGED, "Failed to decode page %d: %s", pgno,
                    sqlite3_errstr(rc));
    return rc;
}
Esempio n. 2
0
/*
 * sqlite3Codec can be called in multiple modes.
 * encrypt mode - expected to return a pointer to the 
 *   encrypted data without altering pData.
 * decrypt mode - expected to return a pointer to pData, with
 *   the data decrypted in the input buffer
 */
void* sqlite3Codec(void *iCtx, void *data, Pgno pgno, int mode) {
  codec_ctx *ctx = (codec_ctx *) iCtx;
  int offset = 0, rc = 0;
  int page_sz = sqlcipher_codec_ctx_get_pagesize(ctx); 
  unsigned char *pData = (unsigned char *) data;
  void *buffer = sqlcipher_codec_ctx_get_data(ctx);
  void *kdf_salt = sqlcipher_codec_ctx_get_kdf_salt(ctx);
  CODEC_TRACE(("sqlite3Codec: entered pgno=%d, mode=%d, page_sz=%d\n", pgno, mode, page_sz));

  /* call to derive keys if not present yet */
  if((rc = sqlcipher_codec_key_derive(ctx)) != SQLITE_OK) {
   sqlcipher_codec_ctx_set_error(ctx, rc); 
   return NULL;
  }

  if(pgno == 1) offset = FILE_HEADER_SZ; /* adjust starting pointers in data page for header offset on first page*/

  CODEC_TRACE(("sqlite3Codec: switch mode=%d offset=%d\n",  mode, offset));
  switch(mode) {
    case 0: /* decrypt */
    case 2:
    case 3:
      if(pgno == 1) memcpy(buffer, SQLITE_FILE_HEADER, FILE_HEADER_SZ); /* copy file header to the first 16 bytes of the page */ 
      rc = sqlcipher_page_cipher(ctx, CIPHER_READ_CTX, pgno, CIPHER_DECRYPT, page_sz - offset, pData + offset, (unsigned char*)buffer + offset);
      if(rc != SQLITE_OK) sqlcipher_codec_ctx_set_error(ctx, rc);
      memcpy(pData, buffer, page_sz); /* copy buffer data back to pData and return */
      return pData;
      break;
    case 6: /* encrypt */
      if(pgno == 1) memcpy(buffer, kdf_salt, FILE_HEADER_SZ); /* copy salt to output buffer */ 
      rc = sqlcipher_page_cipher(ctx, CIPHER_WRITE_CTX, pgno, CIPHER_ENCRYPT, page_sz - offset, pData + offset, (unsigned char*)buffer + offset);
      if(rc != SQLITE_OK) sqlcipher_codec_ctx_set_error(ctx, rc);
      return buffer; /* return persistent buffer data, pData remains intact */
      break;
    case 7:
      if(pgno == 1) memcpy(buffer, kdf_salt, FILE_HEADER_SZ); /* copy salt to output buffer */ 
      rc = sqlcipher_page_cipher(ctx, CIPHER_READ_CTX, pgno, CIPHER_ENCRYPT, page_sz - offset, pData + offset, (unsigned char*)buffer + offset);
      if(rc != SQLITE_OK) sqlcipher_codec_ctx_set_error(ctx, rc);
      return buffer; /* return persistent buffer data, pData remains intact */
      break;
    default:
      return pData;
      break;
  }
}