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Overview
Comment:Avoid the possibility of integer overflow on a pointer comparison test for corruption in the database file.
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SHA1: ff1b1ac3313ba9d70414e928ef3dd82913298a1a
User & Date: drh 2016-03-22 14:10:45
Context
2016-03-22
14:37
Create the "uptr" typedef (the same as uintptr_t when available) and use it to cast pointers before comparison. (check-in: 2484cc0c user: drh tags: trunk)
14:10
Avoid the possibility of integer overflow on a pointer comparison test for corruption in the database file. (check-in: ff1b1ac3 user: drh tags: trunk)
2016-03-21
22:28
Fix harmless compiler warnings. (check-in: 25d776e4 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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  getCellInfo(pCur);
  aPayload = pCur->info.pPayload;
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  bEnd = offset+amt==pCur->info.nPayload;
#endif
  assert( offset+amt <= pCur->info.nPayload );

  if( &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize] ){

    /* Trying to read or write past the end of the data is an error */




    return SQLITE_CORRUPT_BKPT;
  }

  /* Check if data must be read/written to/from the btree page itself. */
  if( offset<pCur->info.nLocal ){
    int a = amt;
    if( a+offset>pCur->info.nLocal ){








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  getCellInfo(pCur);
  aPayload = pCur->info.pPayload;
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  bEnd = offset+amt==pCur->info.nPayload;
#endif
  assert( offset+amt <= pCur->info.nPayload );

  assert( aPayload > pPage->aData );
  if( (aPayload - pPage->aData) > (pBt->usableSize - pCur->info.nLocal) ){
    /* Trying to read or write past the end of the data is an error.  The
    ** conditional above is really:
    **    &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
    ** but is recast into its current form to avoid integer overflow problems
    */
    return SQLITE_CORRUPT_BKPT;
  }

  /* Check if data must be read/written to/from the btree page itself. */
  if( offset<pCur->info.nLocal ){
    int a = amt;
    if( a+offset>pCur->info.nLocal ){
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