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Overview
Comment:Do not allow CREATE TABLE or CREATE VIEW of an object with a name that looks like a shadow table name.
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SHA3-256: 6aef58b629d89955f85f65191ba2be67b2adfac4f0327fe9a7141cb2705dbc00
User & Date: drh 2019-11-16 14:15:19
Context
2019-11-16
16:54
More restrictions on changes to shadow tables when in defensive mode. check-in: bae76a5c user: drh tags: trunk
14:15
Do not allow CREATE TABLE or CREATE VIEW of an object with a name that looks like a shadow table name. Closed-Leaf check-in: 6aef58b6 user: drh tags: defensive-improvements
13:51
Break out the test for writable shadow tables into a separate subroutine. check-in: 8ad34d36 user: drh tags: defensive-improvements
Changes
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Changes to src/build.c.

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    ){
      if( sqlite3Config.bExtraSchemaChecks ){
        sqlite3ErrorMsg(pParse, ""); /* corruptSchema() will supply the error */
        return SQLITE_ERROR;
      }
    }
  }else{
    if( pParse->nested==0 
     && 0==sqlite3StrNICmp(zName, "sqlite_", 7)
    ){
      sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s",
                      zName);
      return SQLITE_ERROR;
    }

  }
  return SQLITE_OK;
}

/*
** Return the PRIMARY KEY index of a table
*/
................................................................................
/*
** Return true if zName is a shadow table name in the current database
** connection.
**
** zName is temporarily modified while this routine is running, but is
** restored to its original value prior to this routine returning.
*/
static int isShadowTableName(sqlite3 *db, char *zName){
  char *zTail;                  /* Pointer to the last "_" in zName */
  Table *pTab;                  /* Table that zName is a shadow of */
  Module *pMod;                 /* Module for the virtual table */

  zTail = strrchr(zName, '_');
  if( zTail==0 ) return 0;
  *zTail = 0;
................................................................................
  if( !IsVirtual(pTab) ) return 0;
  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->azModuleArg[0]);
  if( pMod==0 ) return 0;
  if( pMod->pModule->iVersion<3 ) return 0;
  if( pMod->pModule->xShadowName==0 ) return 0;
  return pMod->pModule->xShadowName(zTail+1);
}
#else
# define isShadowTableName(x,y) 0
#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */

/*
** This routine is called to report the final ")" that terminates
** a CREATE TABLE statement.
**
** The table structure that other action routines have been building
................................................................................
  if( pEnd==0 && pSelect==0 ){
    return;
  }
  assert( !db->mallocFailed );
  p = pParse->pNewTable;
  if( p==0 ) return;

  if( pSelect==0 && isShadowTableName(db, p->zName) ){
    p->tabFlags |= TF_Shadow;
  }

  /* If the db->init.busy is 1 it means we are reading the SQL off the
  ** "sqlite_master" or "sqlite_temp_master" table on the disk.
  ** So do not write to the disk again.  Extract the root page number
  ** for the table from the db->init.newTnum field.  (The page number







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    ){
      if( sqlite3Config.bExtraSchemaChecks ){
        sqlite3ErrorMsg(pParse, ""); /* corruptSchema() will supply the error */
        return SQLITE_ERROR;
      }
    }
  }else{
    if( (pParse->nested==0 && 0==sqlite3StrNICmp(zName, "sqlite_", 7))
     || (sqlite3ReadOnlyShadowTables(db) && sqlite3ShadowTableName(db, zName))
    ){
      sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s",
                      zName);
      return SQLITE_ERROR;
    }

  }
  return SQLITE_OK;
}

/*
** Return the PRIMARY KEY index of a table
*/
................................................................................
/*
** Return true if zName is a shadow table name in the current database
** connection.
**
** zName is temporarily modified while this routine is running, but is
** restored to its original value prior to this routine returning.
*/
int sqlite3ShadowTableName(sqlite3 *db, const char *zName){
  char *zTail;                  /* Pointer to the last "_" in zName */
  Table *pTab;                  /* Table that zName is a shadow of */
  Module *pMod;                 /* Module for the virtual table */

  zTail = strrchr(zName, '_');
  if( zTail==0 ) return 0;
  *zTail = 0;
................................................................................
  if( !IsVirtual(pTab) ) return 0;
  pMod = (Module*)sqlite3HashFind(&db->aModule, pTab->azModuleArg[0]);
  if( pMod==0 ) return 0;
  if( pMod->pModule->iVersion<3 ) return 0;
  if( pMod->pModule->xShadowName==0 ) return 0;
  return pMod->pModule->xShadowName(zTail+1);
}


#endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */

/*
** This routine is called to report the final ")" that terminates
** a CREATE TABLE statement.
**
** The table structure that other action routines have been building
................................................................................
  if( pEnd==0 && pSelect==0 ){
    return;
  }
  assert( !db->mallocFailed );
  p = pParse->pNewTable;
  if( p==0 ) return;

  if( pSelect==0 && sqlite3ShadowTableName(db, p->zName) ){
    p->tabFlags |= TF_Shadow;
  }

  /* If the db->init.busy is 1 it means we are reading the SQL off the
  ** "sqlite_master" or "sqlite_temp_master" table on the disk.
  ** So do not write to the disk again.  Extract the root page number
  ** for the table from the db->init.newTnum field.  (The page number

Changes to src/sqliteInt.h.

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     const sqlite3_module*,
     void*,
     void(*)(void*)
   );
#  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)
#endif
int sqlite3ReadOnlyShadowTables(sqlite3 *db);





int sqlite3VtabEponymousTableInit(Parse*,Module*);
void sqlite3VtabEponymousTableClear(sqlite3*,Module*);
void sqlite3VtabMakeWritable(Parse*,Table*);
void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*, int);
void sqlite3VtabFinishParse(Parse*, Token*);
void sqlite3VtabArgInit(Parse*);
void sqlite3VtabArgExtend(Parse*, Token*);







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     const sqlite3_module*,
     void*,
     void(*)(void*)
   );
#  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)
#endif
int sqlite3ReadOnlyShadowTables(sqlite3 *db);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  int sqlite3ShadowTableName(sqlite3 *db, const char *zName);
#else
# define sqlite3ShadowTableName(A,B) 0
#endif
int sqlite3VtabEponymousTableInit(Parse*,Module*);
void sqlite3VtabEponymousTableClear(sqlite3*,Module*);
void sqlite3VtabMakeWritable(Parse*,Table*);
void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*, int);
void sqlite3VtabFinishParse(Parse*, Token*);
void sqlite3VtabArgInit(Parse*);
void sqlite3VtabArgExtend(Parse*, Token*);

Changes to test/altertab.test.

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    CREATE VIRTUAL TABLE y1 USING fts3;
  }

  do_catchsql_test 16.10 {
    INSERT INTO y1_segments VALUES(1, X'1234567890');
  } {1 {table y1_segments may not be modified}}

  do_catchsql_test 16.20 {
    ALTER TABLE y1_segments RENAME TO abc;
  } {1 {table y1_segments may not be altered}}

  do_catchsql_test 16.21 {
    DROP TABLE y1_segments;
  } {1 {table y1_segments may not be dropped}}

















  do_execsql_test 16.30 {
    ALTER TABLE y1 RENAME TO z1;
  }

  do_execsql_test 16.40 {
    SELECT * FROM z1_segments;








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    CREATE VIRTUAL TABLE y1 USING fts3;
  }

  do_catchsql_test 16.10 {
    INSERT INTO y1_segments VALUES(1, X'1234567890');
  } {1 {table y1_segments may not be modified}}

  do_catchsql_test 16.20 {
    DROP TABLE y1_segments;
  } {1 {table y1_segments may not be dropped}}

  do_catchsql_test 16.20 {
    ALTER TABLE y1_segments RENAME TO abc;
  } {1 {table y1_segments may not be altered}}
  sqlite3_db_config db DEFENSIVE 0
  do_catchsql_test 16.22 {
    ALTER TABLE y1_segments RENAME TO abc;
  } {0 {}}
  sqlite3_db_config db DEFENSIVE 1
  do_catchsql_test 16.23 {
    CREATE TABLE y1_segments AS SELECT * FROM abc;
  } {1 {object name reserved for internal use: y1_segments}}
  do_catchsql_test 16.24 {
    CREATE VIEW y1_segments AS SELECT * FROM abc;
  } {1 {object name reserved for internal use: y1_segments}}
  sqlite3_db_config db DEFENSIVE 0
  do_catchsql_test 16.25 {
    ALTER TABLE abc RENAME TO y1_segments;
  } {0 {}}
  sqlite3_db_config db DEFENSIVE 1

  do_execsql_test 16.30 {
    ALTER TABLE y1 RENAME TO z1;
  }

  do_execsql_test 16.40 {
    SELECT * FROM z1_segments;