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Overview
Comment:When inserting a row into a child table, invoke the authorization callback to request permission to read the parent key columns.
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SHA1: 9842f2d5f606eb8f641ecae9fbc5368b8d7e4286
User & Date: dan 2009-10-02 14:23:42
Context
2009-10-02
15:29
Add one more authentication test to fkey2.test to cover an untested branch. check-in: e4fa8be7 user: dan tags: trunk
14:23
When inserting a row into a child table, invoke the authorization callback to request permission to read the parent key columns. check-in: 9842f2d5 user: dan tags: trunk
06:35
Add a test to check that the incrblob API cannot be used to write to an IPK column. Also a comment to explain why the incrblob code does not need to check if a column is part of a parent key before writing to it. check-in: dca2a7f6 user: dan tags: trunk
Changes
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Changes to src/auth.c.

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** Write an error message into pParse->zErrMsg that explains that the
** user-supplied authorization function returned an illegal value.
*/
static void sqliteAuthBadReturnCode(Parse *pParse){
  sqlite3ErrorMsg(pParse, "authorizer malfunction");
  pParse->rc = SQLITE_ERROR;
}




































/*
** The pExpr should be a TK_COLUMN expression.  The table referred to
** is in pTabList or else it is the NEW or OLD table of a trigger.  
** Check to see if it is OK to read this particular column.
**
** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN 
................................................................................
void sqlite3AuthRead(
  Parse *pParse,        /* The parser context */
  Expr *pExpr,          /* The expression to check authorization on */
  Schema *pSchema,      /* The schema of the expression */
  SrcList *pTabList     /* All table that pExpr might refer to */
){
  sqlite3 *db = pParse->db;
  int rc;
  Table *pTab = 0;      /* The table being read */
  const char *zCol;     /* Name of the column of the table */
  int iSrc;             /* Index in pTabList->a[] of table being read */
  const char *zDBase;   /* Name of database being accessed */
  int iDb;              /* The index of the database the expression refers to */
  int iCol;             /* Index of column in table */

  if( db->xAuth==0 ) return;
  iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
  if( iDb<0 ){
    /* An attempt to read a column out of a subquery or other
................................................................................
  }else if( pTab->iPKey>=0 ){
    assert( pTab->iPKey<pTab->nCol );
    zCol = pTab->aCol[pTab->iPKey].zName;
  }else{
    zCol = "ROWID";
  }
  assert( iDb>=0 && iDb<db->nDb );
  zDBase = db->aDb[iDb].zName;
  rc = db->xAuth(db->pAuthArg, SQLITE_READ, pTab->zName, zCol, zDBase, 
                 pParse->zAuthContext);
  if( rc==SQLITE_IGNORE ){
    pExpr->op = TK_NULL;
  }else if( rc==SQLITE_DENY ){
    if( db->nDb>2 || iDb!=0 ){
      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited", 
         zDBase, pTab->zName, zCol);
    }else{
      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited",pTab->zName,zCol);
    }
    pParse->rc = SQLITE_AUTH;
  }else if( rc!=SQLITE_OK ){
    sqliteAuthBadReturnCode(pParse);
  }
}

/*
** Do an authorization check using the code and arguments given.  Return
** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_DENY
** is returned, then the error count and error message in pParse are
** modified appropriately.







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** Write an error message into pParse->zErrMsg that explains that the
** user-supplied authorization function returned an illegal value.
*/
static void sqliteAuthBadReturnCode(Parse *pParse){
  sqlite3ErrorMsg(pParse, "authorizer malfunction");
  pParse->rc = SQLITE_ERROR;
}

/*
** Invoke the authorization callback for permission to read column zCol from
** table zTab in database zDb. This function assumes that an authorization
** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
**
** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
** is treated as SQLITE_DENY. In this case an error is left in pParse.
*/
void sqlite3AuthReadCol(
  Parse *pParse,                  /* The parser context */
  const char *zTab,               /* Table name */
  const char *zCol,               /* Column name */
  int iDb,                        /* Index of containing database. */
  Expr *pExpr                     /* Optional expression */
){
  sqlite3 *db = pParse->db;       /* Database handle */
  char *zDb = db->aDb[iDb].zName; /* Name of attached database */
  int rc;                         /* Auth callback return code */

  rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext);
  if( rc!=SQLITE_IGNORE && rc!=SQLITE_DENY && rc!=SQLITE_OK ){
    sqliteAuthBadReturnCode(pParse);
  }else if( rc==SQLITE_IGNORE && pExpr ){
    pExpr->op = TK_NULL;
  }else if( rc!=SQLITE_OK ){
    if( db->nDb>2 || iDb!=0 ){
      sqlite3ErrorMsg(pParse, "access to %s.%s.%s is prohibited",zDb,zTab,zCol);
    }else{
      sqlite3ErrorMsg(pParse, "access to %s.%s is prohibited", zTab, zCol);
    }
    pParse->rc = SQLITE_AUTH;
  }
}

/*
** The pExpr should be a TK_COLUMN expression.  The table referred to
** is in pTabList or else it is the NEW or OLD table of a trigger.  
** Check to see if it is OK to read this particular column.
**
** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN 
................................................................................
void sqlite3AuthRead(
  Parse *pParse,        /* The parser context */
  Expr *pExpr,          /* The expression to check authorization on */
  Schema *pSchema,      /* The schema of the expression */
  SrcList *pTabList     /* All table that pExpr might refer to */
){
  sqlite3 *db = pParse->db;

  Table *pTab = 0;      /* The table being read */
  const char *zCol;     /* Name of the column of the table */
  int iSrc;             /* Index in pTabList->a[] of table being read */

  int iDb;              /* The index of the database the expression refers to */
  int iCol;             /* Index of column in table */

  if( db->xAuth==0 ) return;
  iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
  if( iDb<0 ){
    /* An attempt to read a column out of a subquery or other
................................................................................
  }else if( pTab->iPKey>=0 ){
    assert( pTab->iPKey<pTab->nCol );
    zCol = pTab->aCol[pTab->iPKey].zName;
  }else{
    zCol = "ROWID";
  }
  assert( iDb>=0 && iDb<db->nDb );








  sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb, pExpr);







}

/*
** Do an authorization check using the code and arguments given.  Return
** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY.  If SQLITE_DENY
** is returned, then the error count and error message in pParse are
** modified appropriately.

Changes to src/fkey.c.

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      iCol = pFKey->aCol[0].iFrom;
      aiCol = &iCol;
    }
    for(i=0; i<pFKey->nCol; i++){
      if( aiCol[i]==pTab->iPKey ){
        aiCol[i] = -1;
      }







    }

    /* Take a shared-cache advisory read-lock on the parent table. Allocate 
    ** a cursor to use to search the unique index on the parent key columns 
    ** in the parent table.  */
    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
    pParse->nTab++;







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      iCol = pFKey->aCol[0].iFrom;
      aiCol = &iCol;
    }
    for(i=0; i<pFKey->nCol; i++){
      if( aiCol[i]==pTab->iPKey ){
        aiCol[i] = -1;
      }
#ifndef SQLITE_OMIT_AUTHORIZATION
      /* Request permission to read the parent key columns. */
      if( db->xAuth ){
        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;
        sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb, 0);
      }
#endif
    }

    /* Take a shared-cache advisory read-lock on the parent table. Allocate 
    ** a cursor to use to search the unique index on the parent key columns 
    ** in the parent table.  */
    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
    pParse->nTab++;

Changes to src/sqliteInt.h.

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void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
void sqlite3DeferForeignKey(Parse*, int);
#ifndef SQLITE_OMIT_AUTHORIZATION
  void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);
  int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
  void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
  void sqlite3AuthContextPop(AuthContext*);

#else
# define sqlite3AuthRead(a,b,c,d)
# define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
# define sqlite3AuthContextPush(a,b,c)
# define sqlite3AuthContextPop(a)  ((void)(a))
#endif
void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);







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void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
void sqlite3DeferForeignKey(Parse*, int);
#ifndef SQLITE_OMIT_AUTHORIZATION
  void sqlite3AuthRead(Parse*,Expr*,Schema*,SrcList*);
  int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
  void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
  void sqlite3AuthContextPop(AuthContext*);
  void sqlite3AuthReadCol(Parse*, const char *, const char *, int, Expr *);
#else
# define sqlite3AuthRead(a,b,c,d)
# define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
# define sqlite3AuthContextPush(a,b,c)
# define sqlite3AuthContextPop(a)  ((void)(a))
#endif
void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);

Changes to test/fkey2.test.

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} {1}
do_test fkey2-17.2.9 {
  expr [db total_changes] - $nTotal
} {4}
do_test fkey2-17.2.10 {
  execsql { SELECT * FROM high ; SELECT * FROM low }
} {}


#-------------------------------------------------------------------------
# Test that the authorization callback works.
#





































execsql { PRAGMA count_changes = 0 }





























#-------------------------------------------------------------------------
# The following block of tests, those prefixed with "fkey2-genfkey.", are 
# the same tests that were used to test the ".genfkey" command provided 
# by the shell tool. So these tests show that the built-in foreign key 
# implementation is more or less compatible with the triggers generated 
# by genfkey.
#







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} {1}
do_test fkey2-17.2.9 {
  expr [db total_changes] - $nTotal
} {4}
do_test fkey2-17.2.10 {
  execsql { SELECT * FROM high ; SELECT * FROM low }
} {}
execsql { PRAGMA count_changes = 0 }

#-------------------------------------------------------------------------
# Test that the authorization callback works.
#

ifcapable auth {
  do_test fkey2-18.1 {
    execsql {
      CREATE TABLE long(a, b PRIMARY KEY, c);
      CREATE TABLE short(d, e, f REFERENCES long);
      CREATE TABLE mid(g, h, i REFERENCES long DEFERRABLE INITIALLY DEFERRED);
    }
  } {}

  proc auth {args} {eval lappend ::authargs $args ; return SQLITE_OK}
  db auth auth

  # An insert on the parent table must read the child key of any deferred
  # foreign key constraints. But not the child key of immediate constraints.
  set authargs {}
  do_test fkey2-18.2 {
    execsql { INSERT INTO long VALUES(1, 2, 3) }
    set authargs
  } {SQLITE_INSERT long {} main {} SQLITE_READ mid i main {}}

  # An insert on the child table of an immediate constraint must read the
  # parent key columns (to see if it is a violation or not).
  set authargs {}
  do_test fkey2-18.3 {
    execsql { INSERT INTO short VALUES(1, 3, 2) }
    set authargs
  } {SQLITE_INSERT short {} main {} SQLITE_READ long b main {}}
  
  # As must an insert on the child table of a deferred constraint.
  set authargs {}
  do_test fkey2-18.4 {
    execsql { INSERT INTO mid VALUES(1, 3, 2) }
    set authargs
  } {SQLITE_INSERT mid {} main {} SQLITE_READ long b main {}}

  do_test fkey2-18.5 {
    execsql {
      CREATE TABLE nought(a, b PRIMARY KEY, c);
      CREATE TABLE cross(d, e, f,
        FOREIGN KEY(e) REFERENCES nought(b) ON UPDATE CASCADE
      );
    }
    execsql { INSERT INTO nought VALUES(2, 1, 2) }
    execsql { INSERT INTO cross VALUES(0, 1, 0) }
    set authargs [list]
    execsql { UPDATE nought SET b = 5 }
    set authargs
  } {SQLITE_UPDATE nought b main {} SQLITE_READ cross e main {} SQLITE_READ cross e main {} SQLITE_READ nought b main {} SQLITE_READ nought b main {} SQLITE_READ nought b main {} SQLITE_UPDATE cross e main {} SQLITE_READ nought b main {} SQLITE_READ cross e main {} SQLITE_READ nought b main {} SQLITE_READ nought b main {}}

  do_test fkey2-18.6 {
    execsql {SELECT * FROM cross}
  } {0 5 0}

  rename auth {}
  proc auth {args} {
    if {[lindex $args 1] == "long"} {return SQLITE_IGNORE}
    return SQLITE_OK
  }
  do_test fkey2-18.7 {
    catchsql { INSERT INTO short VALUES(1, 3, 2) }
  } {1 {access to long.b is prohibited}}

  db auth {}
  unset authargs
}

#-------------------------------------------------------------------------
# The following block of tests, those prefixed with "fkey2-genfkey.", are 
# the same tests that were used to test the ".genfkey" command provided 
# by the shell tool. So these tests show that the built-in foreign key 
# implementation is more or less compatible with the triggers generated 
# by genfkey.
#