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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

Artifact 4aabd06cff3fe759e3e658bcc17b71789710665e:


# 2004 August 30 {}
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests to make sure SQLite does not crash or
# segfault if it sees a corrupt database file.
#
# $Id: corrupt.test,v 1.12 2009/07/13 09:41:45 danielk1977 Exp $

catch {forcedelete test.db test.db-journal test.bu}

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Do not use a codec for tests in this file, as the database file is
# manipulated directly using tcl scripts (using the [hexio_write] command).
#
do_not_use_codec

# Construct a large database for testing.
#
do_test corrupt-1.1 {
  execsql {
    BEGIN;
    CREATE TABLE t1(x);
    INSERT INTO t1 VALUES(randstr(100,100));
    INSERT INTO t1 VALUES(randstr(90,90));
    INSERT INTO t1 VALUES(randstr(80,80));
    INSERT INTO t1 SELECT x || randstr(5,5) FROM t1;
    INSERT INTO t1 SELECT x || randstr(6,6) FROM t1;
    INSERT INTO t1 SELECT x || randstr(7,7) FROM t1;
    INSERT INTO t1 SELECT x || randstr(8,8) FROM t1;
    INSERT INTO t1 VALUES(randstr(3000,3000));
    INSERT INTO t1 SELECT x || randstr(9,9) FROM t1;
    INSERT INTO t1 SELECT x || randstr(10,10) FROM t1;
    INSERT INTO t1 SELECT x || randstr(11,11) FROM t1;
    INSERT INTO t1 SELECT x || randstr(12,12) FROM t1;
    CREATE INDEX t1i1 ON t1(x);
    CREATE TABLE t2 AS SELECT * FROM t1;
    DELETE FROM t2 WHERE rowid%5!=0;
    COMMIT;
  }
} {}
integrity_check corrupt-1.2

# Setup for the tests.  Make a backup copy of the good database in test.bu.
# Create a string of garbage data that is 256 bytes long.
#
forcecopy test.db test.bu
set fsize [file size test.db]
set junk "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
while {[string length $junk]<256} {append junk $junk}
set junk [string range $junk 0 255]

# Go through the database and write garbage data into each 256 segment
# of the file.  Then do various operations on the file to make sure that
# the database engine can recover gracefully from the corruption.
#
for {set i [expr {1*256}]} {$i<$fsize-256} {incr i 256} {
  set tn [expr {$i/256}]
  db close
  forcecopy test.bu test.db
  set fd [open test.db r+]
  fconfigure $fd -translation binary
  seek $fd $i
  puts -nonewline $fd $junk
  close $fd
  do_test corrupt-2.$tn.1 {
    sqlite3 db test.db
    catchsql {SELECT count(*) FROM sqlite_master}
    set x {}
  } {}
  do_test corrupt-2.$tn.2 {
    catchsql {SELECT count(*) FROM t1}
    set x {}
  } {}
  do_test corrupt-2.$tn.3 {
    catchsql {SELECT count(*) FROM t1 WHERE x>'abcdef'}
    set x {}
  } {}
  do_test corrupt-2.$tn.4 {
    catchsql {SELECT count(*) FROM t2}
    set x {}
  } {}
  do_test corrupt-2.$tn.5 {
    catchsql {CREATE TABLE t3 AS SELECT * FROM t1}
    set x {}
  } {}
  do_test corrupt-2.$tn.6 {
    catchsql {DROP TABLE t1}
    set x {}
  } {}
  do_test corrupt-2.$tn.7 {
    catchsql {PRAGMA integrity_check}
    set x {}
  } {}

  # Check that no page references were leaked.
  do_test corrupt-2.$tn.8 {
    set bt [btree_from_db db]
    db_enter db
    array set stats [btree_pager_stats $bt]
    db_leave db
    set stats(ref)
  } {0}
}  

#------------------------------------------------------------------------
# For these tests, swap the rootpage entries of t1 (a table) and t1i1 (an
# index on t1) in sqlite_master. Then perform a few different queries
# and make sure this is detected as corruption.
#
do_test corrupt-3.1 {
  db close
  forcecopy test.bu test.db
  sqlite3 db test.db
  list
} {}
do_test corrupt-3.2 {
  set t1_r [execsql {SELECT rootpage FROM sqlite_master WHERE name = 't1i1'}]
  set t1i1_r [execsql {SELECT rootpage FROM sqlite_master WHERE name = 't1'}]
  set cookie [expr [execsql {PRAGMA schema_version}] + 1]
  execsql "
    PRAGMA writable_schema = 1;
    UPDATE sqlite_master SET rootpage = $t1_r WHERE name = 't1';
    UPDATE sqlite_master SET rootpage = $t1i1_r WHERE name = 't1i1';
    PRAGMA writable_schema = 0;
    PRAGMA schema_version = $cookie;
  "
} {}

# This one tests the case caught by code in checkin [2313].
do_test corrupt-3.3 {
  db close
  sqlite3 db test.db
  catchsql {
    INSERT INTO t1 VALUES('abc');
  }
} {1 {database disk image is malformed}}
do_test corrupt-3.4 {
  db close
  sqlite3 db test.db
  catchsql {
    SELECT * FROM t1;
  }
} {1 {database disk image is malformed}}
do_test corrupt-3.5 {
  db close
  sqlite3 db test.db
  catchsql {
    SELECT * FROM t1 WHERE oid = 10;
  }
} {1 {database disk image is malformed}}
do_test corrupt-3.6 {
  db close
  sqlite3 db test.db
  catchsql {
    SELECT * FROM t1 WHERE x = 'abcde';
  }
} {1 {database disk image is malformed}}

do_test corrupt-4.1 {
  db close
  forcedelete test.db test.db-journal
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    CREATE TABLE t1(a INTEGER PRIMARY KEY, b TEXT);
  }
  for {set i 0} {$i < 10} {incr i} {
    set text [string repeat $i 220]
    execsql { INSERT INTO t1 VALUES($i, $text) }
  }
  execsql { CREATE INDEX i1 ON t1(b) }
} {}
do_test corrupt-4.2 {
  set iRoot [db one {SELECT rootpage FROM sqlite_master WHERE name = 'i1'}]
  set iOffset [hexio_get_int [hexio_read test.db [expr 12+($iRoot-1)*1024] 2]]
  set data [hexio_render_int32 [expr $iRoot - 1]]
  hexio_write test.db [expr ($iRoot-1)*1024 + $iOffset] $data
  db close
  sqlite3 db test.db

  # The following DELETE statement attempts to delete a cell stored on the
  # root page of index i1. After this cell is deleted it must be replaced
  # by a cell retrieved from the child page (a leaf) of the deleted cell.
  # This will fail, as the block modified the database image so that the
  # child page of the deleted cell is from a table (intkey) b-tree, not an
  # index b-tree as expected. At one point this was causing an assert()
  # to fail.
  catchsql { DELETE FROM t1 WHERE rowid = 3 }
} {1 {database disk image is malformed}}

do_test corrupt-5.1 {
  db close
  forcedelete test.db test.db-journal
  sqlite3 db test.db

  execsql { PRAGMA page_size = 1024 }
  set ct "CREATE TABLE t1(c0 "
  set i 0
  while {[string length $ct] < 950} { append ct ", c[incr i]" }
  append ct ")"
  execsql $ct
} {}

do_test corrupt-5.2 {
  db close
  hexio_write test.db 108 00000000 
  sqlite3 db test.db
  catchsql { SELECT * FROM sqlite_master }
} {1 {database disk image is malformed}}

# At one point, the specific corruption caused by this test case was
# causing a buffer overwrite. Although a crash was never demonstrated,
# running this testcase under valgrind revealed the problem.
do_test corrupt-6.1 {
  db close
  forcedelete test.db test.db-journal
  sqlite3 db test.db
  execsql { 
    PRAGMA page_size = 1024; CREATE TABLE t1(x);
  }

  # The root page of t1 is 1024 bytes in size. The header is 8 bytes, and
  # each of the cells inserted by the following INSERT statements consume
  # 16 bytes (including the 2 byte cell-offset array entry). So the page
  # can contain up to 63 cells.
  for {set i 0} {$i < 63} {incr i} {
    execsql { INSERT INTO t1 VALUES( randomblob(10) ) }
  }

  # Free the cell stored right at the end of the page (at offset pgsz-14).
  execsql { DELETE FROM t1 WHERE rowid=1 }
  set rootpage [db one {SELECT rootpage FROM sqlite_master WHERE name = 't1'}]
  db close

  set offset [expr ($rootpage * 1024)-14+2]
  hexio_write test.db $offset 00FF
  sqlite3 db test.db 

  catchsql { INSERT INTO t1 VALUES( randomblob(10) ) }
} {1 {database disk image is malformed}}

ifcapable oversize_cell_check {
  db close
  forcedelete test.db test.db-journal
  sqlite3 db test.db
  execsql { 
    PRAGMA page_size = 1024; CREATE TABLE t1(x);
  }

  do_test corrupt-7.1 {
    for {set i 0} {$i < 39} {incr i} {
      execsql {
        INSERT INTO t1 VALUES(X'000100020003000400050006000700080009000A');
      }
    }
  } {}
  db close
  
  # Corrupt the root page of table t1 so that the first offset in the 
  # cell-offset array points to the data for the SQL blob associated with
  # record (rowid=10). The root page still passes the checks in btreeInitPage(),
  # because the start of said blob looks like the start of a legitimate 
  # page cell.
  #
  # Test case cc-2 overwrites the blob so that it no longer looks like a
  # real cell. But, by the time it is overwritten, btreeInitPage() has already
  # initialized the root page, so no corruption is detected.
  #
  # Test case cc-3 inserts an extra record into t1, forcing balance-deeper
  # to run. After copying the contents of the root page to the new child,
  # btreeInitPage() is called on the child. This time, it detects corruption
  # (because the start of the blob associated with the (rowid=10) record
  # no longer looks like a real cell). At one point the code assumed that 
  # detecting corruption was not possible at that point, and an assert() failed.
  #
  set fd [open test.db r+]
  fconfigure $fd -translation binary -encoding binary
  seek $fd [expr 1024+8]
  puts -nonewline $fd "\x03\x14"
  close $fd
  
  sqlite3 db test.db
  do_test corrupt-7.2 {
    execsql { 
      UPDATE t1 SET x = X'870400020003000400050006000700080009000A' 
      WHERE rowid = 10;
    }
  } {}
  do_test corrupt-7.3 {
    catchsql {
      INSERT INTO t1 VALUES(X'000100020003000400050006000700080009000A');
    }
  } {1 {database disk image is malformed}}
}

db close
forcedelete test.db test.db-journal
do_test corrupt-8.1 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    PRAGMA secure_delete = on;
    PRAGMA auto_vacuum = 0;
    CREATE TABLE t1(x INTEGER PRIMARY KEY, y);
    INSERT INTO t1 VALUES(5, randomblob(1900));
  }

  hexio_write test.db 2044 [hexio_render_int32 2]
  hexio_write test.db 24   [hexio_render_int32 45]

  catchsql { INSERT OR REPLACE INTO t1 VALUES(5, randomblob(1900)) }
} {1 {database disk image is malformed}}

db close
forcedelete test.db test.db-journal
do_test corrupt-8.2 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    PRAGMA secure_delete = on;
    PRAGMA auto_vacuum = 0;
    CREATE TABLE t1(x INTEGER PRIMARY KEY, y);
    INSERT INTO t1 VALUES(5, randomblob(900));
    INSERT INTO t1 VALUES(6, randomblob(900));
  }

  hexio_write test.db 2047 FF
  hexio_write test.db 24   [hexio_render_int32 45]

  catchsql { INSERT INTO t1 VALUES(4, randomblob(1900)) }
} {1 {database disk image is malformed}}

finish_test