Subject: [PATCH]  Do not allow CREATE TABLE or CREATE VIEW of an object with a name

 that looks like a shadow table name.

diff --git a/src/build.c b/src/build.c

index 3412670..f273394 100644

--- a/src/build.c

+++ b/src/build.c

@@ -814,6 +814,22 @@ int sqlite3WritableSchema(sqlite3 *db){

   return (db->flags&(SQLITE_WriteSchema|SQLITE_Defensive))==SQLITE_WriteSchema;

 }

+/*

+** Return TRUE if shadow tables should be read-only in the current

+** context.

+*/

+int sqlite3ReadOnlyShadowTables(sqlite3 *db){

+#ifndef SQLITE_OMIT_VIRTUALTABLE

+  if( (db->flags & SQLITE_Defensive)!=0

+   && db->pVtabCtx==0

+   && db->nVdbeExec==0

+  ){

+    return 1;

+  }

+#endif

+  return 0;

+}

+

 /*

 ** This routine is used to check if the UTF-8 string zName is a legal

 ** unqualified name for a new schema object (table, index, view or

@@ -822,9 +838,10 @@ int sqlite3WritableSchema(sqlite3 *db){

 ** is reserved for internal use.

 */

 int sqlite3CheckObjectName(Parse *pParse, const char *zName){

-  if( !pParse->db->init.busy && pParse->nested==0 

+  if(( !pParse->db->init.busy && pParse->nested==0 

           && sqlite3WritableSchema(pParse->db)==0

-          && 0==sqlite3StrNICmp(zName, "sqlite_", 7) ){

+          && 0==sqlite3StrNICmp(zName, "sqlite_", 7) ) ||

+          (sqlite3ReadOnlyShadowTables(pParse->db) && sqlite3ShadowTableName(pParse->db, zName))){

     sqlite3ErrorMsg(pParse, "object name reserved for internal use: %s", zName);

     return SQLITE_ERROR;

   }

@@ -1929,7 +1946,7 @@ int sqlite3IsShadowTableOf(sqlite3 *db, Table *pTab, const char *zName){

 ** 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){

+int sqlite3ShadowTableName(sqlite3 *db, const char *zName){

   char *zTail;                  /* Pointer to the last "_" in zName */

   Table *pTab;                  /* Table that zName is a shadow of */

@@ -1942,8 +1959,6 @@ static int isShadowTableName(sqlite3 *db, char *zName){

   if( !IsVirtual(pTab) ) return 0;

   return sqlite3IsShadowTableOf(db, pTab, zName);

 }

-#else

-# define isShadowTableName(x,y) 0

 #endif /* ifndef SQLITE_OMIT_VIRTUALTABLE */

 /*

@@ -1985,7 +2000,7 @@ void sqlite3EndTable(

   p = pParse->pNewTable;

   if( p==0 ) return;

-  if( pSelect==0 && isShadowTableName(db, p->zName) ){

+  if( pSelect==0 && sqlite3ShadowTableName(db, p->zName) ){

     p->tabFlags |= TF_Shadow;

   }

diff --git a/src/sqliteInt.h b/src/sqliteInt.h

index 60b2ebd..e5ba8a0 100644

--- a/src/sqliteInt.h

+++ b/src/sqliteInt.h

@@ -4408,6 +4408,11 @@ void sqlite3AutoLoadExtensions(sqlite3*);

    );

 #  define sqlite3VtabInSync(db) ((db)->nVTrans>0 && (db)->aVTrans==0)

 #endif

+#ifndef SQLITE_OMIT_VIRTUALTABLE

+  int sqlite3ShadowTableName(sqlite3 *db, const char *zName);

+#else

+# define sqlite3ShadowTableName(A,B) 0

+#endif

 #ifndef SQLITE_OMIT_VIRTUALTABLE

   int sqlite3IsShadowTableOf(sqlite3*,Table*,const char*);

 #else

diff --git a/test/altertab.test b/test/altertab.test

index 891b081..0705abc 100644

--- a/test/altertab.test

+++ b/test/altertab.test

@@ -547,13 +547,29 @@ ifcapable fts3 {

   } {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_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;

   }