Bug 10175 - pidentd lookups reports root user when using rlogin.
pidentd lookups reports root user when using rlogin.
Product: Red Hat Linux
Classification: Retired
Component: pidentd (Show other bugs)
i386 Linux
medium Severity medium
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Assigned To: Trond Eivind Glomsrxd
Depends On:
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Reported: 2000-03-14 16:56 EST by Jesper Brouer
Modified: 2008-05-01 11:37 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2000-05-14 17:05:04 EDT
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Description Jesper Brouer 2000-03-14 16:56:35 EST
pidentd lookups reports root user when using rlogin.

This problem only occurs on RedHat6.1, it works fine on RedHat6.0.

When I use rlogin to login on an remote server, pidentd reports USERID as
"root".  If I use telnet the USERID is correct.

syslog when using rlogin: (fx: rlogin
Mar 14 22:43:24 host2 in.identd[6011]: reply to 1023 , 513 :

syslog when using telnet: (fx: telnet
Mar 14 22:49:42 host2 in.identd[6045]: reply to 1833 , 23 :

I have tried to upgrade and "downgrade" to different version of pidentd.

I have tried the following rpm packages on both RedHat6.1 and RedHat6.0:
 ((XX) <== specifices which RH version the rpm originally belongs to)

   pidentd-2.8.5-3  (RedHat6.0)
   pidentd-3.0.7-5  (RedHat6.1)
   pidentd-3.0.10-2 (RedHat6.2beta)

All my tests concludes that any version of pidentd on RedHat6.0 works
perfectly, and none of the versions works on RedHat6.1.
Comment 1 Jeff Johnson 2000-05-14 17:05:59 EDT
I don't believe this is a pidentd problem, as it "works for me" when I
rlogin localhost and check /var/log/messages (Red Hat 6.2/sparc with
pidentd-3.0.10-5). You might want to check /etc/pam.d/rlogin, as I dimly
remember a last minute change there. FWIW, here's what I have:

auth       sufficient   /lib/security/pam_rhosts_auth.so
auth       required     /lib/security/pam_securetty.so
auth       required     /lib/security/pam_pwdb.so shadow nullok
auth       required     /lib/security/pam_nologin.so
account    required     /lib/security/pam_pwdb.so
password   required     /lib/security/pam_cracklib.so
password   required     /lib/security/pam_pwdb.so shadow nullok use_authtok
session    required     /lib/security/pam_pwdb.so
Comment 2 Christoffer Hall-Frederiksen 2000-06-30 16:40:50 EDT
It has nothing to do with PAM!

When I rlogin to a host, the host throws a ident-lookup back 
at the machine I come from. If I use rlogin I get the answer
'root' not my username. But if I use telnet I get the right 
result. So the problem must be the suid-bit on rlogin.  It must 
be a uid,euid problem since all identd does is lookup the uid
of whoever owns the tcp-connection.

Comment 3 Christoffer Hall-Frederiksen 2000-06-30 19:24:13 EDT
OK .... mystery solved!

The problem is as follows:

pidentd wants the uid of a connection. It looks up i /proc/net/tcp
to see who owns the given connection. The problems is that /proc/net/tcp
lists the euid and not the uid. Since rlogin is suid-root it gets euid 0
and that is why identd return root and not the real name. 

Now the big one ... how to solve it ;) I'ev asked on linux-kernel
if euid is really what should be listed in /proc/net/tcp.

  Christoffer (hall@diku.dk)

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