Bug 139262

Summary: useradd does not allow "dot" or "at" in usernames
Product: [Fedora] Fedora Reporter: shrek-m <shrek-m>
Component: shadow-utilsAssignee: Eido Inoue <havill>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 3CC: leonid, paroque28
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Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2004-11-15 20:04:08 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description shrek-m 2004-11-14 17:03:27 UTC
Description of problem:
useradd does not allow "dot""." or "at""@" in usernames

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. try to add new users with "." or "@"

Actual Results:
# LANG=C useradd test.test
useradd: invalid user name 'test.test'

# LANG=C useradd test@test
useradd: invalid user name 'test@test'

# LANG=C useradd testtest

Expected Results:  should be possible without editing /etc/passwd
/etc/group /etc/shadow

# grep test.test /etc/passwd /etc/group /etc/shadow | awk -F: '{print
$1 "\t" $2 }'
/etc/passwd     test.test
/etc/group      test.test
/etc/shadow     test.test

Additional info:
<=rhl 7.3 it is possible
afair "." is not possible since rhl8.0, rhl9, fc1, fc2, fc3

info for cyrus-imapd
--man imapd.conf--
unixhierarchysep: 0
Use the UNIX separator character  �/�  for  delimiting  levels  of
mailbox  hierarchy.   The  default is to use the netnews separator
character �.�

you have to change it to "1" for enabling dot-users - local_accounts
> cm user/test.test

Comment 1 Leonid Mamtchenkov 2004-11-15 14:35:20 UTC
I don't have a problem with dot "." in usernames.  The version of
shadow-utils is shadow-utils-4.0.3-40 though.  at "@" doesn't work for
me either, but than I am not so sure it should.

Comment 2 shrek-m 2004-11-15 19:48:17 UTC
# rpm -q shadow-utils
# useradd other.test

"." is ok now

for "@" i agree.
it was possible in rhl 7.3 (and other unbelievable combinations)
but i am not sure if it should really work.

if "@" is not ok in usernames ( shrek-m@gmx.net ) than this bug
can be closed.


Comment 3 Eido Inoue 2004-11-15 20:04:08 UTC
as per release 38 changelog, "@" is not ok in usernames:

- conform to posix for user/group name input checking [def 3.426
  and 3.189] which is posix portable filename character set [3.276]
  while disallowing dash for first char as recommended, and disallow
  dollar sign)

only "[A-Za-z0-9._][A-Za-z0-9._-]*" is allowed (with a special
exception made for samba machine names, by option, in release 41 and

Comment 4 Pablo Rodriguez 2018-05-04 17:27:51 UTC
On IEEE Std 1003.1-2017 standard available at https://ieeexplore.ieee.org/document/8277153/

And also on IEEE Std 1003.1-2001 available at http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap06.html#tag_06_01

You should use the 6.1 Portable Character Set that includes some special characters (see section 3.426 User Name)