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Overview
Comment:Avoid an out-of-bounds read on a recovery attempt using a carefully crafted database and rollback journal with mismatched page sizes. The test case for this is in TH3.
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SHA3-256: 378afa16381a222aafa6009dbbbc92473a69683537f1c265694678b0595a42c8
User & Date: drh 2017-09-14 02:36:27
References
2017-09-18
09:40
The out-of-bounds read on recovery fix of check-in [378afa16381a222a] caused problems for some corner-case error conditions. This alternative fix appears to work better. (check-in: 74f399d8 user: drh tags: trunk)
Context
2017-09-14
20:41
Avoid an out-of-bounds read that can be caused by a specially constructed journal file. (check-in: cf5bf42c user: dan tags: trunk)
02:36
Avoid an out-of-bounds read on a recovery attempt using a carefully crafted database and rollback journal with mismatched page sizes. The test case for this is in TH3. (check-in: 378afa16 user: drh tags: trunk)
2017-09-13
20:20
Test case update due to PRAGMA integrity_check enhancements in [8525c30c]. No changes to code. (check-in: 43c6023b user: drh tags: trunk)
Changes
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Changes to src/pager.c.

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  pPager->journalOff = 0;
  needPagerReset = isHot;

  /* This loop terminates either when a readJournalHdr() or 
  ** pager_playback_one_page() call returns SQLITE_DONE or an IO error 
  ** occurs. 
  */
  while( 1 ){

    /* Read the next journal header from the journal file.  If there are
    ** not enough bytes left in the journal file for a complete header, or
    ** it is corrupted, then a process must have failed while writing it.
    ** This indicates nothing more needs to be rolled back.
    */

    rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
    if( rc!=SQLITE_OK ){ 
      if( rc==SQLITE_DONE ){
        rc = SQLITE_OK;
      }
      goto end_playback;
    }







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  pPager->journalOff = 0;
  needPagerReset = isHot;

  /* This loop terminates either when a readJournalHdr() or 
  ** pager_playback_one_page() call returns SQLITE_DONE or an IO error 
  ** occurs. 
  */

  do{
    /* Read the next journal header from the journal file.  If there are
    ** not enough bytes left in the journal file for a complete header, or
    ** it is corrupted, then a process must have failed while writing it.
    ** This indicates nothing more needs to be rolled back.
    */
    u32 savedPageSize = pPager->pageSize;
    rc = readJournalHdr(pPager, isHot, szJ, &nRec, &mxPg);
    if( rc!=SQLITE_OK ){ 
      if( rc==SQLITE_DONE ){
        rc = SQLITE_OK;
      }
      goto end_playback;
    }
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          ** so that no further harm will be done.  Perhaps the next
          ** process to come along will be able to rollback the database.
          */
          goto end_playback;
        }
      }
    }
  }
  /*NOTREACHED*/

  assert( 0 );

end_playback:
  /* Following a rollback, the database file should be back in its original
  ** state prior to the start of the transaction, so invoke the
  ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
  ** assertion that the transaction counter was modified.
  */







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          ** so that no further harm will be done.  Perhaps the next
          ** process to come along will be able to rollback the database.
          */
          goto end_playback;
        }
      }
    }


    rc = sqlite3PagerSetPagesize(pPager, &savedPageSize, -1);
  }while( rc==SQLITE_OK );

end_playback:
  /* Following a rollback, the database file should be back in its original
  ** state prior to the start of the transaction, so invoke the
  ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
  ** assertion that the transaction counter was modified.
  */