user-record: Handle invalid uid/gid case

I'm not that familiar with outer code to guide Coverity with an
assert(), so consider invalid uid/gid as non-matching in order to avoid
-EINVAL for bit shifts calculation.

Fixes: CID#1590746

src/shared/group-record.c

@@ -350,6 +350,9 @@ int group_record_match(GroupRecord *h, const UserDBMatch *match) {
         if (!match)
                 return true;
 
+        if (!gid_is_valid(h->gid))
+                return false;
+
         if (h->gid < match->gid_min || h->gid > match->gid_max)
                 return false;
 

src/shared/user-record.c

@@ -2775,6 +2775,9 @@ int user_record_match(UserRecord *u, const UserDBMatch *match) {
         if (!match)
                 return true;
 
+        if (!uid_is_valid(u->uid))
+                return false;
+
         if (u->uid < match->uid_min || u->uid > match->uid_max)
                 return false;