Bug 6191 – su: Segmentation fault

Bug 6191 - su: Segmentation fault

Summary:	su: Segmentation fault

Status:	CLOSED RAWHIDE

Aliases:	None

Product:	Red Hat Linux
Classification:	Retired
Component:	pam (Show other bugs)
Sub Component:
Version:	6.1
Hardware:	i386 Linux

Priority	high Severity high
Target Milestone:	---
Target Release:	---
Assigned To:	Cristian Gafton
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Reported:	1999-10-21 13:31 EDT by vadim
Modified:	2008-05-01 11:37 EDT (History)
CC List:	1 user (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
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Last Closed:	2000-02-05 17:13:27 EST
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Description vadim 1999-10-21 13:31:14 EDT

Redhat 6.1 standart configuration from CD, (ISO from
ftp.sunet.se)

PC: Intel Pentium III 450 MHz, 256 RAM, SCSI hard drive, S3
TrioV2 video adapter.

When run as normal user "su" - receive "Segmentation fault"

Comment 1 vadim 1999-10-22 04:56:59 EDT

problem only with certain types telnet programs.
RedHat 5.2, Slackware 4.0 - such problems have not.

Comment 2 Tomasz Kepczynski 1999-12-21 03:12:59 EST

I have seen very similar problem but for root user. 'su' command without '-'
(like for example 'su news') ends up with segmentation fault (but I wasn't able
to produce core dump even with unlimited coredumpsize). 'su - news' works
fine.
'su' itself from normal user account prompts for password and works fine.
This bug causes segfault from '/etc/cron.daily/slrnpull-expire'.
The problem shows itself when logged on console and from kdm. I haven't tried
remote logins nor gdm.

Comment 3 Tomasz Kepczynski 2000-01-13 14:58:59 EST

The problem seems to be related to pam_xauth module and probably should be
solved there. To reproduce a fault you need two things: be logged as root and
have empty DISPLAY variable (so that getenv("DISPLAY") returns empty string,
not NULL). Then try su anybody and thats it.
I suppose the problem lies in pam_xauth.c at line 484 when you try to
free the pointer returned by getenv. I am quite sure you can't do that (but
man page doesn't say a word about it).
pam is pam 0.68-7

Comment 4 Nalin Dahyabhai 2000-02-05 17:13:59 EST

tomkep@3net.pl hit it exactly.  This will be fixed in pam-0.72-6 and later in
Raw Hide and future releases.

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