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Old 12-09-2004, 09:10 AM   #1
LQ Newbie
Registered: Nov 2004
Distribution: FC2
Posts: 23

Rep: Reputation: 15
ssh fails to authenticate some users

Hi there, I am experiencing a weird problem with ssh.

Most of users here use the passwordless login mode when using ssh. However, after upgrading from RH9 to FC2, some of them are unable to keep login in such a way.

As root, I su - to such users, and did some test, using ssh -v -v <server> from the client, and starting sshd -d -d in the server, and find out that for such users, the following occurred

debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Trying private key: /home/german/.ssh/identity
debug1: Trying private key: /home/german/.ssh/id_rsa
debug1: Offering public key: /home/german/.ssh/id_dsa
debug2: we sent a publickey packet, wait for reply
Connection closed by
debug1: Calling cleanup 0x8062d00(0x0)

and in the server

debug2: input_userauth_request: try method publickey
debug1: test whether pkalg/pkblob are acceptable
debug1: PAM setting rhost to ""
debug2: monitor_read: 41 used once, disabling now
debug2: monitor_read: 3 used once, disabling now
debug1: temporarily_use_uid: 1007/109 (e=0/0)
getgroups: Invalid argument
debug1: Calling cleanup 0x8063d50(0x0)
debug1: Calling cleanup 0x806f3f0(0x0)

So apparently, there is a problem when doing getgroups(). This problem is not present for other users though...

I have been googling for an answer to this problem, no luck...

Any ideas??
Old 12-10-2004, 08:43 AM   #2
LQ Newbie
Registered: Nov 2004
Distribution: FC2
Posts: 23

Original Poster
Rep: Reputation: 15
Ok, finally I have been able to know the reason of my problem, posting it here in case somebody else has the same problem:

- the users experiencing this problem belong to more than 32 groups, which is the value of NGROUPS_MAX in /usr/include/linux/limits.h

Posible solutions: to increase this number and recompile the kernel :S or to re-organize the groups (I think I will go for this choice).


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