BUG #14927: Unchecked SearchSysCache1() return value

The following bug has been logged on the website:

Bug reference:      14927
Logged by:          Pan Bian
Email address:      bianpan2016@163.com
PostgreSQL version: 10.1
Operating system:   Linux
Description:

File: postgresql-10.1/src/backend/catalog/heap.c
Function: heap_drop_with_catalog
Line: 1771

Function SearchSysCache1() may return a NULL pointer, but in
heap_drop_with_catalog(), its return value is not validated before it is
dereferenced. To avoid NULL dereference, it is better to check the return
value of SearchSysCache1() against NULL.

For your convenience, I paste related codes as follows:

1771     tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
1772     if (((Form_pg_class) GETSTRUCT(tuple))->relispartition)
1773     {
1774         parentOid = get_partition_parent(relid);
1775         LockRelationOid(parentOid, AccessExclusiveLock);
1776     }
1777 
1778     ReleaseSysCache(tuple);


Thank you!

Pan Bian