/ Check-in [8353808c]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Fix the DROP TABLE command so that it cannot be used to bypass foreign key constraints (if foreign key support is enabled).
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:8353808c9e70412fdee31bfda7810e948f1c7485
User & Date: dan 2009-09-28 14:49:02
Context
2009-09-28
18:52
Ignore foreign key mismatch errors while compiling DROP TABLE commands. check-in: 5b4d4637 user: dan tags: trunk
14:49
Fix the DROP TABLE command so that it cannot be used to bypass foreign key constraints (if foreign key support is enabled). check-in: 8353808c user: dan tags: trunk
11:54
Fix some foreign key constraint related problems that occur when a row refers to itself. check-in: 9e503e2d user: dan tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/build.c.

2057
2058
2059
2060
2061
2062
2063

2064
2065
2066
2067
2068
2069
2070
    sqlite3BeginWriteOperation(pParse, 1, iDb);

#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      sqlite3VdbeAddOp0(v, OP_VBegin);
    }
#endif


    /* Drop all triggers associated with the table being dropped. Code
    ** is generated to remove entries from sqlite_master and/or
    ** sqlite_temp_master if required.
    */
    pTrigger = sqlite3TriggerList(pParse, pTab);
    while( pTrigger ){







>







2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
    sqlite3BeginWriteOperation(pParse, 1, iDb);

#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      sqlite3VdbeAddOp0(v, OP_VBegin);
    }
#endif
    sqlite3FkDropTable(pParse, pName, pTab);

    /* Drop all triggers associated with the table being dropped. Code
    ** is generated to remove entries from sqlite_master and/or
    ** sqlite_temp_master if required.
    */
    pTrigger = sqlite3TriggerList(pParse, pTab);
    while( pTrigger ){

Changes to src/fkey.c.

582
583
584
585
586
587
588


























































589
590
591
592
593
594
595
    sqlite3ExprDelete(dbMem, pStep->pWhere);
    sqlite3ExprListDelete(dbMem, pStep->pExprList);
    sqlite3SelectDelete(dbMem, pStep->pSelect);
    sqlite3ExprDelete(dbMem, p->pWhen);
    sqlite3DbFree(dbMem, p);
  }
}



























































/*
** This function is called when inserting, deleting or updating a row of
** table pTab to generate VDBE code to perform foreign key constraint 
** processing for the operation.
**
** For a DELETE operation, parameter regOld is passed the index of the







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
    sqlite3ExprDelete(dbMem, pStep->pWhere);
    sqlite3ExprListDelete(dbMem, pStep->pExprList);
    sqlite3SelectDelete(dbMem, pStep->pSelect);
    sqlite3ExprDelete(dbMem, p->pWhen);
    sqlite3DbFree(dbMem, p);
  }
}

/*
** This function is called to generate code that runs when table pTab is
** being dropped from the database. The SrcList passed as the second argument
** to this function contains a single entry guaranteed to resolve to
** table pTab.
**
** Normally, no code is required. However, if either
**
**   (a) The table is the parent table of a FK constraint, or
**   (b) The table is the child table of a deferred FK constraint and it is
**       determined at runtime that there are outstanding deferred FK 
**       constraint violations in the database,
**
** then the equivalent of "DELETE FROM <tbl>" is executed before dropping
** the table from the database. Triggers are disabled while running this
** DELETE, but foreign key actions are not.
*/
void sqlite3FkDropTable(Parse *pParse, SrcList *pName, Table *pTab){
  sqlite3 *db = pParse->db;
  if( (db->flags&SQLITE_ForeignKeys) && !IsVirtual(pTab) && !pTab->pSelect ){
    int iSkip = 0;
    Vdbe *v = sqlite3GetVdbe(pParse);

    assert( v );                  /* VDBE has already been allocated */
    if( sqlite3FkReferences(pTab)==0 ){
      /* Search for a deferred foreign key constraint for which this table
      ** is the child table. If one cannot be found, return without 
      ** generating any VDBE code. If one can be found, then jump over
      ** the entire DELETE if there are no outstanding deferred constraints
      ** when this statement is run.  */
      FKey *p;
      for(p=pTab->pFKey; p; p=p->pNextFrom){
        if( p->isDeferred ) break;
      }
      if( !p ) return;
      iSkip = sqlite3VdbeMakeLabel(v);
      sqlite3VdbeAddOp2(v, OP_FkIfZero, 1, iSkip);
    }

    pParse->disableTriggers = 1;
    sqlite3DeleteFrom(pParse, sqlite3SrcListDup(db, pName, 0), 0);
    pParse->disableTriggers = 0;

    /* If the DELETE has generated immediate foreign key constraint 
    ** violations, halt the VDBE and return an error at this point, before
    ** any modifications to the schema are made. This is because statement
    ** transactions are not able to rollback schema changes.  */
    sqlite3VdbeAddOp2(v, OP_FkIfZero, 0, sqlite3VdbeCurrentAddr(v)+2);
    sqlite3HaltConstraint(
        pParse, OE_Abort, "foreign key constraint failed", P4_STATIC
    );

    if( iSkip ){
      sqlite3VdbeResolveLabel(v, iSkip);
    }
  }
}

/*
** This function is called when inserting, deleting or updating a row of
** table pTab to generate VDBE code to perform foreign key constraint 
** processing for the operation.
**
** For a DELETE operation, parameter regOld is passed the index of the

Changes to src/sqliteInt.h.

2118
2119
2120
2121
2122
2123
2124

2125
2126
2127
2128
2129
2130
2131
....
2945
2946
2947
2948
2949
2950
2951

2952
2953
2954
2955
2956
2957
2958
2959
2960

2961
2962
2963
2964
2965
2966
2967

  /* Information used while coding trigger programs. */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  u32 oldmask;         /* Mask of old.* columns referenced */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */


  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nVarExpr;        /* Number of used slots in apVarExpr[] */
  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
................................................................................
** key functionality is available. If OMIT_TRIGGER is defined but
** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
** this case foreign keys are parsed, but no other functionality is 
** provided (enforcement of FK constraints requires the triggers sub-system).
*/
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
  void sqlite3FkCheck(Parse*, Table*, ExprList*, int, int);

  void sqlite3FkActions(Parse*, Table*, ExprList*, int);
  int sqlite3FkRequired(Parse*, Table*, ExprList*);
  u32 sqlite3FkOldmask(Parse*, Table*, ExprList*);
  FKey *sqlite3FkReferences(Table *);
#else
  #define sqlite3FkCheck(a,b,c,d,e)
  #define sqlite3FkActions(a,b,c,d)
  #define sqlite3FkRequired(a,b,c) 0
  #define sqlite3FkOldmask(a,b,c)  0

#endif
#ifndef SQLITE_OMIT_FOREIGN_KEY
  void sqlite3FkDelete(Table*);
#else
  #define sqlite3FkDelete(a)
#endif








>







 







>





|
|
|

>







2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
....
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970

  /* Information used while coding trigger programs. */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  u32 oldmask;         /* Mask of old.* columns referenced */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */

  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nVarExpr;        /* Number of used slots in apVarExpr[] */
  int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
................................................................................
** key functionality is available. If OMIT_TRIGGER is defined but
** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
** this case foreign keys are parsed, but no other functionality is 
** provided (enforcement of FK constraints requires the triggers sub-system).
*/
#if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
  void sqlite3FkCheck(Parse*, Table*, ExprList*, int, int);
  void sqlite3FkDropTable(Parse*, SrcList *, Table*);
  void sqlite3FkActions(Parse*, Table*, ExprList*, int);
  int sqlite3FkRequired(Parse*, Table*, ExprList*);
  u32 sqlite3FkOldmask(Parse*, Table*, ExprList*);
  FKey *sqlite3FkReferences(Table *);
#else
  #define sqlite3FkActions(a,b,c,d)
  #define sqlite3FkCheck(a,b,c,d,e)
  #define sqlite3FkDropTable(a,b,c)
  #define sqlite3FkOldmask(a,b,c)  0
  #define sqlite3FkRequired(a,b,c) 0
#endif
#ifndef SQLITE_OMIT_FOREIGN_KEY
  void sqlite3FkDelete(Table*);
#else
  #define sqlite3FkDelete(a)
#endif

Changes to src/trigger.c.

45
46
47
48
49
50
51




52
53
54
55
56
57
58
** To state it another way:  This routine returns a list of all triggers
** that fire off of pTab.  The list will include any TEMP triggers on
** pTab as well as the triggers lised in pTab->pTrigger.
*/
Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
  Schema * const pTmpSchema = pParse->db->aDb[1].pSchema;
  Trigger *pList = 0;                  /* List of triggers to return */





  if( pTmpSchema!=pTab->pSchema ){
    HashElem *p;
    for(p=sqliteHashFirst(&pTmpSchema->trigHash); p; p=sqliteHashNext(p)){
      Trigger *pTrig = (Trigger *)sqliteHashData(p);
      if( pTrig->pTabSchema==pTab->pSchema
       && 0==sqlite3StrICmp(pTrig->table, pTab->zName) 







>
>
>
>







45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
** To state it another way:  This routine returns a list of all triggers
** that fire off of pTab.  The list will include any TEMP triggers on
** pTab as well as the triggers lised in pTab->pTrigger.
*/
Trigger *sqlite3TriggerList(Parse *pParse, Table *pTab){
  Schema * const pTmpSchema = pParse->db->aDb[1].pSchema;
  Trigger *pList = 0;                  /* List of triggers to return */

  if( pParse->disableTriggers ){
    return 0;
  }

  if( pTmpSchema!=pTab->pSchema ){
    HashElem *p;
    for(p=sqliteHashFirst(&pTmpSchema->trigHash); p; p=sqliteHashNext(p)){
      Trigger *pTrig = (Trigger *)sqliteHashData(p);
      if( pTrig->pTabSchema==pTab->pSchema
       && 0==sqlite3StrICmp(pTrig->table, pTab->zName) 

Changes to test/fkey2.test.

71
72
73
74
75
76
77

78
79
80
81
82
83

84
85
86
87
88
89
90
# fkey2-genfkey.*: Tests that were used with the shell tool .genfkey
#            command. Recycled to test the built-in implementation.
#


proc drop_all_tables {{db db}} {
  set tbls [execsql {SELECT name FROM sqlite_master WHERE type = 'table'}]

  foreach t [execsql {
    SELECT name FROM sqlite_master 
    WHERE type = 'table' AND name NOT like 'sqlite_%'
  }] {
    execsql "DROP TABLE $t"
  }

}

execsql { PRAGMA foreign_keys = on }

if 0 {
execsql {
  CREATE TABLE t1(a PRIMARY KEY, b REFERENCES t1);







>






>







71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
# fkey2-genfkey.*: Tests that were used with the shell tool .genfkey
#            command. Recycled to test the built-in implementation.
#


proc drop_all_tables {{db db}} {
  set tbls [execsql {SELECT name FROM sqlite_master WHERE type = 'table'}]
  execsql { PRAGMA foreign_keys = OFF }
  foreach t [execsql {
    SELECT name FROM sqlite_master 
    WHERE type = 'table' AND name NOT like 'sqlite_%'
  }] {
    execsql "DROP TABLE $t"
  }
  execsql { PRAGMA foreign_keys = ON }
}

execsql { PRAGMA foreign_keys = on }

if 0 {
execsql {
  CREATE TABLE t1(a PRIMARY KEY, b REFERENCES t1);

Changes to test/fkey3.test.

44
45
46
47
48
49
50
51




























52
} {1 {foreign key constraint failed}}

do_test fkey3-1.3 {
  catchsql {
    DROP TABLE t1;
  }
} {1 {foreign key constraint failed}}
 




























finish_test







|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>

44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
} {1 {foreign key constraint failed}}

do_test fkey3-1.3 {
  catchsql {
    DROP TABLE t1;
  }
} {1 {foreign key constraint failed}}

do_test fkey3-1.4 {
  execsql {
    DROP TABLE t2;
  }
} {}

do_test fkey3-1.5 {
  execsql {
    DROP TABLE t1;
  }
} {}

do_test fkey3-2.1 {
  execsql {
    PRAGMA foreign_keys=ON;
    CREATE TABLE t1(x INTEGER PRIMARY KEY);
    INSERT INTO t1 VALUES(100);
    INSERT INTO t1 VALUES(101);
    CREATE TABLE t2(y INTEGER PRIMARY KEY REFERENCES t1 (x) ON UPDATE SET NULL);
  }
  execsql {
    INSERT INTO t2 VALUES(100);
    INSERT INTO t2 VALUES(101);
    SELECT 1, x FROM t1;
    SELECT 2, y FROM t2;
  }
} {1 100 1 101 2 100 2 101}

finish_test