Bug 1979658

Summary: [RFE] RFE for restricting systemd reserved UID (66535)
Product: Red Hat Enterprise Linux 8 Reporter: Daniel Chong <dchong>
Component: shadow-utilsAssignee: Iker Pedrosa <ipedrosa>
Status: CLOSED WONTFIX QA Contact: sssd-qe <sssd-qe>
Severity: low Docs Contact:
Priority: low    
Version: 8.3CC: aboscatt, dbodnarc, dvolkov, ipedrosa, pbrezina
Target Milestone: betaKeywords: FutureFeature
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Hardware: Unspecified   
OS: Linux   
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Fixed In Version: Doc Type: Enhancement
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Last Closed: 2021-08-23 18:32:28 UTC Type: Bug
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Description Daniel Chong 2021-07-06 16:23:06 UTC 
Description of problem:

According to the link(https://systemd.io/UIDS-GIDS/), UID of 65535, aka 16bit (uid_t) -1 → Before Linux kernel 2.4 uid_t used to be 16bit, and programs compiled for that would hence assume that (uid_t) -1 is 65535. This UID is hence not usable either.

Since UID of 66535 is not usable UID, a customer expects useradd command not to assign any users with this UID.  


   https://access.redhat.com/solutions/6009451


How reproducible:
always

Steps to Reproduce:
Actual results:
1. Create a user with 66535 UID for a test user
2. Create a custom systemd unit and add User=test
3. Start a custom service and it will fail



Expected results:

useradd command should not assign a user with a UID of 66536 since it's not usable UID.