When trying to shadow a user with uid 4294967290 the following error are reported to log files:
2018-04-16 12:12:17 INFO vsmserver.shadow: User with uid 0 requested shadowing of 127.0.0.1:10 (uid -6)
2018-04-16 12:12:17 WARNING vsmserver: 'getpwuid(): uid not found' when trying to lookup username corresponding to uid=-6
2018-04-16 12:12:17 WARNING vsmserver.session: shadow_session: User with uid -6 does not exist
This happens when one tries to "end existing session"
2018-04-16 12:17:35 INFO vsmserver.session: User with uid 4294967290 requested termination of 127.0.0.1:10
2018-04-16 12:17:35 WARNING vsmserver: 'getpwuid(): uid not found' when trying to lookup username corresponding to uid=-6
2018-04-16 12:17:35 WARNING vsmserver.session: kill_session: User with uid -6 does not exist
A common scenario where you get large UIDs is sssd's automatic mapping of ActiveD irectory SIDs. Fortunately, the default configuration keeps things within 31 bits, so this bug should not trigger unless people are running something odd.