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      1 # 2007 May 10
      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 # This file implements regression tests for SQLite library.  The focus
     12 # of this file is checking the libraries response to subtly corrupting
     13 # the database file by changing the values of pseudo-randomly selected
     14 # bytes.
     15 #
     16 # $Id: fuzz3.test,v 1.3 2009/01/05 17:19:03 drh Exp $
     17 
     18 set testdir [file dirname $argv0]
     19 source $testdir/tester.tcl
     20 
     21 
     22 expr srand(123)
     23 
     24 proc rstring {n} {
     25   set str s
     26   while {[string length $str] < $n} {
     27     append str [expr rand()]
     28   }
     29   return [string range $str 0 $n]
     30 }
     31 
     32 # Return a randomly generated SQL literal.
     33 #
     34 proc rvalue {} {
     35   switch -- [expr int(rand()*5)] {
     36     0 { # SQL NULL value.
     37       return NULL 
     38     }
     39     1 { # Integer value.
     40       return [expr int(rand()*1024)] 
     41     }
     42     2 { # Real value.
     43       return [expr rand()] 
     44     }
     45     3 { # String value.
     46       set n [expr int(rand()*2500)]
     47       return "'[rstring $n]'"
     48     }
     49     4 { # Blob value.
     50       set n [expr int(rand()*2500)]
     51       return "CAST('[rstring $n]' AS BLOB)"
     52     }
     53   }
     54 }
     55 
     56 proc db_checksum {} {
     57   set    cksum [execsql { SELECT md5sum(a, b, c) FROM t1 }]
     58   append cksum [execsql { SELECT md5sum(d, e, f) FROM t2 }]
     59   set cksum
     60 }
     61 
     62 # Modify a single byte in the file 'test.db' using tcl IO commands. The
     63 # argument value, which must be an integer, determines both the offset of
     64 # the byte that is modified, and the value that it is set to. The lower
     65 # 8 bits of iMod determine the new byte value. The offset of the byte
     66 # modified is the value of ($iMod >> 8).
     67 #
     68 # The return value is the iMod value required to restore the file
     69 # to its original state. The command:
     70 #
     71 #   modify_database [modify_database $x]
     72 #
     73 # leaves the file in the same state as it was in at the start of the
     74 # command (assuming that the file is at least ($x>>8) bytes in size).
     75 #
     76 proc modify_database {iMod} {
     77   set blob [binary format c [expr {$iMod&0xFF}]]
     78   set offset [expr {$iMod>>8}]
     79 
     80   set fd [open test.db r+]
     81   fconfigure $fd -encoding binary -translation binary
     82   seek $fd $offset
     83   set old_blob [read $fd 1]
     84   seek $fd $offset
     85   puts -nonewline $fd $blob
     86   close $fd
     87 
     88   binary scan $old_blob c iOld
     89   return [expr {($offset<<8) + ($iOld&0xFF)}]
     90 }
     91 
     92 proc purge_pcache {} {
     93   ifcapable !memorymanage {
     94     db close
     95     sqlite3 db test.db
     96   } else {
     97     sqlite3_release_memory 10000000
     98   }
     99   if {[lindex [pcache_stats] 1] != 0} {
    100     error "purge_pcache failed: [pcache_stats]"
    101   }
    102 }
    103 
    104 # This block creates a database to work with. 
    105 #
    106 do_test fuzz3-1 {
    107   execsql {
    108     BEGIN;
    109     CREATE TABLE t1(a, b, c);
    110     CREATE TABLE t2(d, e, f);
    111     CREATE INDEX i1 ON t1(a, b, c);
    112     CREATE INDEX i2 ON t2(d, e, f);
    113   }
    114   for {set i 0} {$i < 50} {incr i} {
    115     execsql "INSERT INTO t1 VALUES([rvalue], [rvalue], [rvalue])"
    116     execsql "INSERT INTO t2 VALUES([rvalue], [rvalue], [rvalue])"
    117   }
    118   execsql COMMIT
    119 } {}
    120 
    121 set ::cksum [db_checksum]
    122 do_test fuzz3-2 {
    123   db_checksum
    124 } $::cksum
    125 
    126 for {set ii 0} {$ii < 5000} {incr ii} {
    127   purge_pcache
    128 
    129   # Randomly modify a single byte of the database file somewhere within
    130   # the first 100KB of the file.
    131   set iNew [expr int(rand()*5*1024*256)]
    132   set iOld [modify_database $iNew]
    133 
    134   set iTest 0
    135   foreach sql {
    136     {SELECT * FROM t2 ORDER BY d}      
    137     {SELECT * FROM t1}                 
    138     {SELECT * FROM t2}                 
    139     {SELECT * FROM t1 ORDER BY a}      
    140     {SELECT * FROM t1 WHERE a = (SELECT a FROM t1 WHERE rowid=25)} 
    141     {SELECT * FROM t2 WHERE d = (SELECT d FROM t2 WHERE rowid=1)}  
    142     {SELECT * FROM t2 WHERE d = (SELECT d FROM t2 WHERE rowid=50)} 
    143     {PRAGMA integrity_check}           
    144   } {
    145     do_test fuzz3-$ii.$iNew.[incr iTest] {
    146       foreach {rc msg} [catchsql $sql] {}
    147       if {$rc == 0 
    148        || $msg eq "database or disk is full"
    149        || $msg eq "database disk image is malformed"
    150        || $msg eq "file is encrypted or is not a database"
    151        || [string match "malformed database schema*" $msg]
    152       } {
    153         set msg ok
    154       }
    155       set msg
    156     } {ok}
    157   }
    158 
    159   # Restore the original database file content. Test that the correct 
    160   # checksum is now returned.
    161   #
    162   purge_pcache
    163   modify_database $iOld
    164   do_test fuzz3-$ii.$iNew.[incr iTest] {
    165     db_checksum
    166   } $::cksum
    167 }
    168 
    169 finish_test
    170