1# 2009 June 3 2# 3# The author disclaims copyright to this source code. In place of 4# a legal notice, here is a blessing: 5# 6# May you do good and not evil. 7# May you find forgiveness for yourself and forgive others. 8# May you share freely, never taking more than you give. 9# 10#*********************************************************************** 11# 12# $Id: corruptD.test,v 1.2 2009/06/05 17:09:12 drh Exp $ 13 14set testdir [file dirname $argv0] 15source $testdir/tester.tcl 16 17# Do not use a codec for tests in this file, as the database file is 18# manipulated directly using tcl scripts (using the [hexio_write] command). 19# 20do_not_use_codec 21 22# These tests deal with corrupt database files 23# 24database_may_be_corrupt 25 26#-------------------------------------------------------------------------- 27# OVERVIEW 28# 29# This test file attempts to verify that SQLite does not read past the 30# end of any in-memory buffers as a result of corrupted database page 31# images. Usually this happens because a field within a database page 32# that contains an offset to some other structure within the same page 33# is set to too large a value. A database page contains the following 34# such fields: 35# 36# 1. The page header field that contains the offset to the first 37# free block of space. 38# 39# 2. The first two bytes of all but the last free block on the free-block 40# list (the offset to the next free block). 41# 42# 3. The page header field containing the number of cells on the page 43# (implicitly defines the offset to the final element in the cell offset 44# array, which could potentially be off the end of the page). 45# 46# 4. The page header field containing the offset to the start of the cell 47# content area. 48# 49# 5. The contents of the cell offset array. 50# 51# 6. The first few bytes of each cell determine the size of the cell 52# stored within the page, and hence the offset to the final byte of 53# the cell. 54# 55# If any of the above fields are set to too large a value, then a buffer 56# overread may occur. This test script creates and operates on various 57# strategically corrupted database files to attempt to provoke such buffer 58# overreads. 59# 60# Very often, a buffer overread passes unnoticed, particularly in workstation 61# environments. For this reason, this test script should be run using valgrind 62# (or similar) in order to verify that no overreads occur. 63# 64# TEST PLAN 65# 66# Test cases corruptD-1.* are white-box tests. They attempt to corrupt 67# one of the above fields, then exercise each part of the code in btree.c 68# that uses said field. 69# 70# Offset variables 1, 2, 3 and 4 are all checked to make sure they 71# will not result in buffer overruns as part of page initialization in 72# sqlite3BtreeInitPage(). Offsets 5 and 6 cannot be tested as part of 73# page initialization, as trying to do so causes a performance hit. 74# 75 76do_test corruptD-1.0 { 77 execsql { 78 PRAGMA auto_vacuum = 0; 79 PRAGMA page_size = 1024; 80 CREATE TABLE t1(a, b); 81 CREATE INDEX i1 ON t1(a, b); 82 } 83 for {set ii 1} {$ii < 50} {incr ii} { 84 execsql { INSERT INTO t1 VALUES($ii, $ii * $ii) } 85 } 86 execsql { 87 DELETE FROM t1 WHERE a = 10; 88 DELETE FROM t1 WHERE a = 20; 89 DELETE FROM t1 WHERE a = 30; 90 DELETE FROM t1 WHERE a = 40; 91 } 92 forcecopy test.db test.bu 93} {} 94 95proc incr_change_counter {} { 96 hexio_write test.db 24 [ 97 hexio_render_int32 [expr [hexio_get_int [hexio_read test.db 24 4]] + 1] 98 ] 99} 100 101proc restore_file {} { 102 db close 103 forcecopy test.bu test.db 104 sqlite3 db test.db 105} 106 107#------------------------------------------------------------------------- 108# The following tests, corruptD-1.1.*, focus on the page header field 109# containing the offset of the first free block in a page. 110# 111do_test corruptD-1.1.1 { 112 incr_change_counter 113 hexio_write test.db [expr 1024+1] FFFF 114 catchsql { PRAGMA quick_check } 115} {0 {{*** in database main *** 116Page 2: free space corruption}}} 117do_test corruptD-1.1.2 { 118 incr_change_counter 119 hexio_write test.db [expr 1024+1] [hexio_render_int32 1021] 120 catchsql { SELECT * FROM t1 ORDER BY rowid } 121} {1 {database disk image is malformed}} 122 123#------------------------------------------------------------------------- 124# The following tests, corruptD-1.2.*, focus on the offsets contained 125# in the first 2 byte of each free-block on the free-list. 126# 127do_test corruptD-1.2.1 { 128 restore_file 129} {} 130do_test corruptD-1.2.2 { 131} {} 132 133#------------------------------------------------------------------------- 134# The following tests, corruptD-1.4.*, ... 135# 136 137 138#------------------------------------------------------------------------- 139# The following tests, corruptD-1.5.*, focus on the offsets contained 140# in the cell offset array. 141# 142# defragmentPage 143# 144 145finish_test 146