topic Re: UNIX user id limitation in Operating System - HP-UX

UNIX user id limitation

David Land — Mon, 03 Oct 2005 14:24:12 GMT

Is there a way to bypass the 8 character limit for setting up a UNIX user id?

I have a couple of users who's user names are actually longer than 8 characters. I have been having to truncate their user id names to fit this limit.

Is there anyone who can explain to me why HP has this low character limit? Is there a patch I can install that would increase this limit?

Thanks

Re: UNIX user id limitation

A. Clay Stephenson — Mon, 03 Oct 2005 14:30:30 GMT

This is one of those things that even if you can, you really don't want to do. This has been a UNIX feature for decades and any changes will break legacy code.

Re: UNIX user id limitation

baiju_3 — Mon, 03 Oct 2005 15:01:19 GMT

try this

/usr/lbin/modprdef -m maxpwln=80

User can have more than 8 character password .

This is from an earlier forum .I tested this just now and found working .Please test it and update the forum.

thx,
bl.

Re: UNIX user id limitation

Rick Garland — Mon, 03 Oct 2005 15:03:44 GMT

Altrhough the OS has been upgraded to accept longer names, applications and some utilities still have the 8 character limit. NIS is a case in point. Even though the OS will let you have >8 characters, NIS wants no more than 8

Re: UNIX user id limitation

David Land — Mon, 03 Oct 2005 15:05:15 GMT

So there is nothing that can be done?

I understand the reasoning as to why the password field will only recognize the first eight characters. Anything after that does not matter. What I don't understand is the reasoning behind having an 8 character limit to the user id.

I will just keep doing what I am doing.

Re: UNIX user id limitation

A. Clay Stephenson — Mon, 03 Oct 2005 15:23:04 GMT

It was simply a standard adopted a long time ago by the various UNIX flavors. Newer definitions of the getpwxxx() functions simply have a pointer to char for the login field (i.e. char *login) and the actual value is dynamically assigned. However, older applications (or modern ports of older applications) often simply have char login[9]; /* 8 + the terminal NUL */ and longer variables will simply overflow into the next field -- often with less than desirable results. In many cases, there won't be program crashes but instead subtle data corruption. Moreover, if you have to maintain accounts on various platforms, you will find that some flavors of UNIX allow more than 8 characters and others do not. The safe play is to stay within the 8 character limit.

Re: UNIX user id limitation

David Land — Mon, 03 Oct 2005 15:31:07 GMT

Okay. Thanks for your help in answering my question.

I wanted to ask just in case there was a way to bypass this limitation.