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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"
problem only with certain types telnet programs. RedHat 5.2, Slackware 4.0 - such problems have not.
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.
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
tomkep hit it exactly. This will be fixed in pam-0.72-6 and later in Raw Hide and future releases.