pete@wvus.wciu.edu (Pete Gregory) (01/15/91)
Hi -
Are there any deadly implications to using long (>8 chars) userid names
in /etc/passwd? Management wants to inflict an archaic userid convention
on me (okay with me, as long as UNIX likes it) that will sometimes result in
user names longer than 8 (sometimes 14) characters long.
* I've conducted a test with three long user names (1st 12 chars identical),
and the system seems to be able to differentiate them okay (including
who owns files).
* everyone will have to use 'n' option with 'ls', so that duplicate ownership
will not be suspected.
* I have not conducted any network tests (telnet, NFS, etc.)
* we are using Unisys 6000/80 (Sequent S81) hardware, PTX (SysV.3) software.
Comments welcome and appreciated, especially from anyone who tried this and
ran into problems.
Pete Gregory, UNIX SA | pete@wvus.wciu.edu |
World Vision USA/ISD | wciu!wvus!pete ___|___
919 W. Huntingon Dr. | Voice: 818/357-7979 x3347 |
Monrovia, CA 91016 | FAX: 818/303-6212 |
|
Romanian orphans need our help! Call 1-800-777-1229epeterso@houligan.encore.com (Eric Peterson) (01/15/91)
pete@wvus.wciu.edu (Pete Gregory) writes: | Are there any deadly implications to using long (>8 chars) userid names | in /etc/passwd? Management wants to inflict an archaic userid convention | on me (okay with me, as long as UNIX likes it) that will sometimes result in | user names longer than 8 (sometimes 14) characters long. I ran into this problem just yesterday on a System V machine. I found that with a long user ID, I was unable to change my password with /bin/passwd. I was unable to use FTP, since somewhere, either in the client or the server, my ID was being truncated to 8 characters. | * I've conducted a test with three long user names (1st 12 chars identical), | and the system seems to be able to differentiate them okay (including | who owns files). That's because ownership is determined by user ID number, not the login name. | * everyone will have to use 'n' option with 'ls', so that duplicate ownership | will not be suspected. Good luck enforcing this, other than by hacking ls and possibly breaking any scripts or other software that depends upon the lack of the -n option. Why does your management want to support such long ID names, especially ones of varying length? Perhaps it's something similar to what we do here at Encore ... Someone decided that it would be nice to be able to send mail to anyone in the company by merely sending mail to an address consisting of their first initial followed by their complete last name. To do this, the file /usr/lib/aliases maps everyone's first initial and full last name into a real user ID at a real machine location. Some people have IDs that fit this pattern, truncated to 8 characters. Others have only their first name or their initials. But the aliases file takes care of all of these special cases. This may not be what your superiors want necessarily. But there should be some way to accomodate their needs without resorting to long user IDs. Eric -- Eric Peterson <> epeterson@encore.com <> uunet!encore!epeterson Encore Computer Corp. * Ft. Lauderdale, Florida * (305) 587-2900 x 5208 Why did Constantinople get the works? Gung'f abobql'f ohfvarff ohg gur Ghexf.
les@chinet.chi.il.us (Leslie Mikesell) (01/16/91)
In article <70DsV1w163w@wvus.wciu.edu> pete@wvus.wciu.edu (Pete Gregory) writes: >Hi - > >Are there any deadly implications to using long (>8 chars) userid names >in /etc/passwd? Management wants to inflict an archaic userid convention >on me (okay with me, as long as UNIX likes it) that will sometimes result in >user names longer than 8 (sometimes 14) characters long. SysV (as of r3 anyway) mail will deliver anything that matches 8 characters of a passwd file entry to a file name using up to 14 characters of the recipient name. This means that if you have a user "longname1", mail to "longname9" will be accepted with no errors even though no one will be able to retreive it. I think I even had to make a small change to Smail3 to get this right. "Who am I" will fail (SysVr3 again) on long user names but can usually be replaced by $LOGNAME in scripts. Les Mikesell les@chinet.chi.il.us
meissner@osf.org (Michael Meissner) (01/16/91)
In article <70DsV1w163w@wvus.wciu.edu> pete@wvus.wciu.edu (Pete Gregory) writes: | Are there any deadly implications to using long (>8 chars) userid names | in /etc/passwd? Management wants to inflict an archaic userid convention | on me (okay with me, as long as UNIX likes it) that will sometimes result in | user names longer than 8 (sometimes 14) characters long. My username is 8 characters, and with that, I've noticed quirks over the years. Notably, some ls's use a tab after the username, which make ls -l columns unaligned. Another problem is that the .rhost mechanism on older BSD systems won't recognize 8 character names, but that can be crowbar'ed by using hosts.equiv and living with the looser security. -- Michael Meissner email: meissner@osf.org phone: 617-621-8861 Open Software Foundation, 11 Cambridge Center, Cambridge, MA, 02142 Considering the flames and intolerance, shouldn't USENET be spelled ABUSENET?
lyndon@cs.athabascau.ca (Lyndon Nerenberg) (01/18/91)
>| Are there any deadly implications to using long (>8 chars) userid names >| in /etc/passwd? Yes. A lot of Unix implementations have the following line in <stdio.h>: #define L_cuserid 9 This constant defines the size of a char array large enough to hold a login name plus the terminating NULL. Some (not a lot, but some) software uses this constant to size buffers. If the code doesn't check for (strlen(pw->pw_name) < L_cuserid) you're going to have problems. Not all Unix releases document this constant. Under SunOS it's mentioned in the cuserid(3) man page. I would strongly advise that you limit login names to a maximum of eight characters. There are better ways to achieve what you're setting out to do than by overloading the semantics of login names. -- Lyndon Nerenberg VE6BBM / Computing Services / Athabasca University {alberta,cbmvax,mips}!atha!lyndon || lyndon@cs.athabascau.ca Packet: ve6bbm@ve6mc [.ab.can.na] The only thing open about OSF is their mouth. --Chuck Musciano