MDEV-28482 SIGSEGV in get_access_value_from_val_int

also check number of columns

Author: vuvova

mysql-test/main/grant_repair.result

@@ -96,4 +96,13 @@ insert into mysql.servers values(0,0,0,0,0,0,0,0);
 flush privileges;
 ERROR HY000: Cannot load from mysql.servers. The table is probably corrupted
 alter table mysql.servers add column Owner varchar(512) not null default '';
+#
+# MDEV-28482 SIGSEGV in get_access_value_from_val_int
+#
+create temporary table t1 select * from mysql.tables_priv;
+alter table mysql.tables_priv drop column timestamp;
+flush privileges;
+ERROR HY000: Cannot load from mysql.tables_priv. The table is probably corrupted
+alter table mysql.tables_priv add column Timestamp timestamp not null default now() on update now() after grantor;
+replace mysql.tables_priv select * from t1;
 # End of 10.11 tests

mysql-test/main/grant_repair.test

@@ -114,4 +114,14 @@ insert into mysql.servers values(0,0,0,0,0,0,0,0);
 flush privileges;
 alter table mysql.servers add column Owner varchar(512) not null default '';
 
+--echo #
+--echo # MDEV-28482 SIGSEGV in get_access_value_from_val_int
+--echo #
+create temporary table t1 select * from mysql.tables_priv;
+alter table mysql.tables_priv drop column timestamp;
+--error ER_CANNOT_LOAD_FROM_TABLE_V2
+flush privileges;
+alter table mysql.tables_priv add column Timestamp timestamp not null default now() on update now() after grantor;
+replace mysql.tables_priv select * from t1;
+
 --echo # End of 10.11 tests

sql/sql_acl.cc

@@ -901,7 +901,8 @@ class Grant_table_base
           break;
     }
 
-    if (!table->key_info || table->key_info->user_defined_key_parts != pk_parts)
+    if (num_fields() < min_columns || !table->key_info ||
+        table->key_info->user_defined_key_parts != pk_parts)
     {
       my_error(ER_CANNOT_LOAD_FROM_TABLE_V2, MYF(ME_ERROR_LOG),
                table->s->db.str, table->s->table_name.str);