Fix bug #12812 create view calling a function works without execute right on function

Execution rigths on function was checked just before function execution,
thus it was unknown on prepare stage whether user have right to execute 
particular function.

Added access rights checking function which is called right after fixing
Item_func_sp.
This have additional effect that if user don't have rights for execution
query will fail on earlier stage and will not waste resources on optimizing
with failing on execution stage.


sql/item_func.h:
  Fix bug#12812 create view calling a function works without execute right on function
sql/item_func.cc:
  Fix bug#12812 create view calling a function works without execute right on function
  Added function Item_func_sp::check_access() which checks access rights.
  Added function Item_func_sp::fix_field() which calls check_access() after fixing.
  Item_func_sp::execute() now calls to check_access() to check access rights.
mysql-test/t/sp.test:
  Test case for bug#12812 create view calling a function works without execute right on function
mysql-test/r/sp.result:
  Test case for bug#12812 create view calling a function works without execute right on function

mysql-test/r/sp.result

@@ -3193,4 +3193,16 @@ set f1= concat( 'hello', f1 );
 return f1;
 end|
 drop function bug9048|
+drop function if exists bug12812|
+create function bug12812() returns char(2)
+begin
+return 'ok';
+end;
+create user user_bug12812@localhost IDENTIFIED BY 'ABC'|
+SELECT test.bug12812()|
+ERROR 42000: execute command denied to user 'user_bug12812'@'localhost' for routine 'test.bug12812'
+CREATE VIEW v1 AS SELECT test.bug12812()|
+ERROR 42000: execute command denied to user 'user_bug12812'@'localhost' for routine 'test.bug12812'
+DROP USER user_bug12812@localhost|
+drop function bug12812|
 drop table t1,t2;

mysql-test/t/sp.test

@@ -4043,6 +4043,29 @@ begin
 end|
 drop function bug9048|
 
+#
+# BUG#12812 create view calling a function works without execute right
+#           on function
+--disable_warnings
+drop function if exists bug12812|
+--enable_warnings
+create function bug12812() returns char(2)
+begin
+  return 'ok';
+end;
+create user user_bug12812@localhost IDENTIFIED BY 'ABC'|
+--replace_result $MASTER_MYPORT MYSQL_PORT $MASTER_MYSOCK MYSQL_SOCK
+connect (test_user_12812,localhost,user_bug12812,ABC,test)|
+--error 1370
+SELECT test.bug12812()|
+--error 1370
+CREATE VIEW v1 AS SELECT test.bug12812()|
+# Cleanup
+connection default|
+disconnect test_user_12812|
+DROP USER user_bug12812@localhost|
+drop function bug12812|
+
 #
 # BUG#NNNN: New bug synopsis
 #

sql/item_func.cc

@@ -4711,14 +4711,8 @@ Item_func_sp::execute(Item **itp)
   }
 
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
-  if (check_routine_access(thd, EXECUTE_ACL, 
-			   m_sp->m_db.str, m_sp->m_name.str, 0, 0))
+  if (check_access(EXECUTE_ACL, 0, &save_ctx))
     goto error;
-  sp_change_security_context(thd, m_sp, &save_ctx);
-  if (save_ctx.changed && 
-      check_routine_access(thd, EXECUTE_ACL, 
-			   m_sp->m_db.str, m_sp->m_name.str, 0, 0))
-    goto error_check_ctx;
 #endif
   /*
     Disable the binlogging if this is not a SELECT statement. If this is a
@@ -4737,7 +4731,6 @@ Item_func_sp::execute(Item **itp)
 		 ER(ER_FAILED_ROUTINE_BREAK_BINLOG));
 
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
-error_check_ctx:
   sp_restore_security_context(thd, m_sp, &save_ctx);
 #endif
 
@@ -4845,3 +4838,83 @@ Item_func_sp::tmp_table_field(TABLE *t_arg)
 
   DBUG_RETURN(res);
 }
+
+/*
+  Check access rigths to function
+
+  SYNOPSIS
+    check_access()
+    want_access   requested access
+    report_error  whether to set error to thd->net.report_error
+    sp_ctx        sp security context for switching
+
+  RETURN
+    0     Access granted
+    1     Requested access can't be granted or function doesn't exists
+
+  NOTES
+    Checks if requested access to function can be granted to user.
+    If function isn't found yet, it searches function first.
+    If function can't be found or user don't have requested access
+    and report_error is true error is raised.
+    If security context sp_ctx is provided and access can be granted then
+    switch back to previous context isn't performed.
+    In case of access error or if context is not provided then check_access()
+    switches back to previous security context.
+*/
+bool
+Item_func_sp::check_access(ulong want_access, bool report_error, st_sp_security_context *sp_ctx)
+{
+  bool res;
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+  THD *thd= current_thd;
+  st_sp_security_context save_ctx, *curr_ctx= sp_ctx?sp_ctx:&save_ctx;
+  bool ctx_switched= 0;
+  res= 1;
+  if (! m_sp && ! (m_sp= sp_find_function(thd, m_name, TRUE)))
+  {
+    my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "FUNCTION", m_name->m_qname.str);
+    if (report_error)
+      thd->net.report_error= 1;
+    goto error;
+  }
+
+  if (check_routine_access(thd, want_access,
+			   m_sp->m_db.str, m_sp->m_name.str, 0, 0))
+  {
+    if (report_error)
+      thd->net.report_error= 1;
+    goto error;
+  }
+
+  sp_change_security_context(thd, m_sp, curr_ctx);
+  ctx_switched= curr_ctx->changed;
+  if (save_ctx.changed &&
+      check_routine_access(thd, want_access,
+			   m_sp->m_db.str, m_sp->m_name.str, 0, 0))
+  {
+    if (report_error)
+      thd->net.report_error= 1;
+    goto error_check_ctx;
+  }
+  res= 0;
+error_check_ctx:
+  if (ctx_switched && (res || !sp_ctx))
+    sp_restore_security_context(thd, m_sp, curr_ctx);
+error:
+#else
+  res= 0;
+#endif
+  return res;
+};
+
+bool
+Item_func_sp::fix_fields(THD *thd, Item **ref)
+{
+  bool res;
+  DBUG_ASSERT(fixed == 0);
+  res= Item_func::fix_fields(thd, ref);
+  if (!res && check_access(EXECUTE_ACL, 1, NULL))
+    res= 1;
+  return res;
+}

sql/item_func.h

@@ -55,7 +55,7 @@ class Item_func :public Item_result_field
                   NOT_FUNC, NOT_ALL_FUNC,
                   NOW_FUNC, TRIG_COND_FUNC,
                   GUSERVAR_FUNC, COLLATE_FUNC,
-                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC };
+                  EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP };
   enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,
                        OPTIMIZE_EQUAL };
   enum Type type() const { return FUNC_ITEM; }
@@ -1365,6 +1365,7 @@ class Item_func_row_count :public Item_int_func
 
 class sp_head;
 class sp_name;
+struct st_sp_security_context;
 
 class Item_func_sp :public Item_func
 {
@@ -1434,7 +1435,10 @@ class Item_func_sp :public Item_func
     { context= (Name_resolution_context *)cntx; return FALSE; }
 
   void fix_length_and_dec();
+  bool check_access(ulong want_access, bool report_error, st_sp_security_context *sp_ctx);
+  virtual enum Functype functype() const { return FUNC_SP; }
 
+  bool fix_fields(THD *thd, Item **ref);
 };