コード例 #1
0
ファイル: crypto_impl.c プロジェクト: CoderXL/sqlcipher
static int sqlcipher_page_hmac(cipher_ctx *ctx, Pgno pgno, unsigned char *in, int in_sz, unsigned char *out) {
  unsigned char pgno_raw[sizeof(pgno)];
  /* we may convert page number to consistent representation before calculating MAC for
     compatibility across big-endian and little-endian platforms. 

     Note: The public release of sqlcipher 2.0.0 to 2.0.6 had a bug where the bytes of pgno 
     were used directly in the MAC. SQLCipher convert's to little endian by default to preserve
     backwards compatibility on the most popular platforms, but can optionally be configured
     to use either big endian or native byte ordering via pragma. */

  if(ctx->flags & CIPHER_FLAG_LE_PGNO) { /* compute hmac using little endian pgno*/
    sqlcipher_put4byte_le(pgno_raw, pgno);
  } else if(ctx->flags & CIPHER_FLAG_BE_PGNO) { /* compute hmac using big endian pgno */
    sqlite3Put4byte(pgno_raw, pgno); /* sqlite3Put4byte converts 32bit uint to big endian  */
  } else { /* use native byte ordering */
    memcpy(pgno_raw, &pgno, sizeof(pgno));
  }

  /* include the encrypted page data,  initialization vector, and page number in HMAC. This will 
     prevent both tampering with the ciphertext, manipulation of the IV, or resequencing otherwise
     valid pages out of order in a database */ 
  ctx->provider->hmac(
    ctx->provider_ctx, ctx->hmac_key,
    ctx->key_sz, in,
    in_sz, (unsigned char*) &pgno_raw,
    sizeof(pgno), out);
  return SQLITE_OK; 
}
コード例 #2
0
ファイル: backup.c プロジェクト: SCALE-GmbH/sqlcipher
/*
** Parameter zSrcData points to a buffer containing the data for 
** page iSrcPg from the source database. Copy this data into the 
** destination database.
*/
static int backupOnePage(
  sqlite3_backup *p,              /* Backup handle */
  Pgno iSrcPg,                    /* Source database page to backup */
  const u8 *zSrcData,             /* Source database page data */
  int bUpdate                     /* True for an update, false otherwise */
){
  Pager * const pDestPager = sqlite3BtreePager(p->pDest);
  const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc);
  int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest);
  const int nCopy = MIN(nSrcPgsz, nDestPgsz);
  const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz;
#ifdef SQLITE_HAS_CODEC
  /* Use BtreeGetReserveNoMutex() for the source b-tree, as although it is
  ** guaranteed that the shared-mutex is held by this thread, handle
  ** p->pSrc may not actually be the owner.  */
  int nSrcReserve = sqlite3BtreeGetReserveNoMutex(p->pSrc);
  int nDestReserve = sqlite3BtreeGetOptimalReserve(p->pDest);
#endif
  int rc = SQLITE_OK;
  i64 iOff;

  assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 );
  assert( p->bDestLocked );
  assert( !isFatalError(p->rc) );
  assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) );
  assert( zSrcData );

  /* Catch the case where the destination is an in-memory database and the
  ** page sizes of the source and destination differ. 
  */
  if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(pDestPager) ){
    rc = SQLITE_READONLY;
  }

#ifdef SQLITE_HAS_CODEC
  /* Backup is not possible if the page size of the destination is changing
  ** and a codec is in use.
  */
  if( nSrcPgsz!=nDestPgsz && sqlite3PagerGetCodec(pDestPager)!=0 ){
    rc = SQLITE_READONLY;
  }

  /* Backup is not possible if the number of bytes of reserve space differ
  ** between source and destination.  If there is a difference, try to
  ** fix the destination to agree with the source.  If that is not possible,
  ** then the backup cannot proceed.
  */
  if( nSrcReserve!=nDestReserve ){
    u32 newPgsz = nSrcPgsz;
    rc = sqlite3PagerSetPagesize(pDestPager, &newPgsz, nSrcReserve);
    if( rc==SQLITE_OK && newPgsz!=nSrcPgsz ) rc = SQLITE_READONLY;
  }
#endif

  /* This loop runs once for each destination page spanned by the source 
  ** page. For each iteration, variable iOff is set to the byte offset
  ** of the destination page.
  */
  for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){
    DbPage *pDestPg = 0;
    Pgno iDest = (Pgno)(iOff/nDestPgsz)+1;
    if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue;
    if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg, 0))
     && SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg))
    ){
      const u8 *zIn = &zSrcData[iOff%nSrcPgsz];
      u8 *zDestData = sqlite3PagerGetData(pDestPg);
      u8 *zOut = &zDestData[iOff%nDestPgsz];

      /* Copy the data from the source page into the destination page.
      ** Then clear the Btree layer MemPage.isInit flag. Both this module
      ** and the pager code use this trick (clearing the first byte
      ** of the page 'extra' space to invalidate the Btree layers
      ** cached parse of the page). MemPage.isInit is marked 
      ** "MUST BE FIRST" for this purpose.
      */
      memcpy(zOut, zIn, nCopy);
      ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0;
      if( iOff==0 && bUpdate==0 ){
        sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc));
      }
    }
    sqlite3PagerUnref(pDestPg);
  }

  return rc;
}