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Created attachment 1078997[details]
C Prgram for reproducing crash
Prepare new service in /etc/pam.d
[root@host ~]# cat /etc/pam.d/ipsilon_ecp
auth required pam_sss.so
account required pam_sss.so
Compile attached reproducer.
gcc sssd_pam_crash_reproducer.c -o sssd_pam_crash_reproducer -lpam
Expected result:
The pam responder (ssss_pam) should not crash
IPA Server/Client: ipa-server-4.2.0-12.el7.x86_64, ipa-client-4.2.0-12.el7.x86_64
RHEL: 7.2
Tested the bug with following Scenarios:
Scenario A) For sssd-1.13.0-36.el7.x86_64 (Used to reproduce the issue)
observations:
1) Create /etc/pam.d/ipsilon_ecp with paramters:
auth required pam_sss.so
account required pam_sss.so
2) Notice the sssd_pam process id, using ps -elf | grep sssd
(In my case)
4 S root 2580 2549 0 80 0 - 59732 ep_pol 16:55 ? 00:00:00 /usr/libexec/sssd/sssd_pam --uid 0 --gid 0 --debug-to-files
3) Now run the GCC compiler for the attached C program
gcc sssd_pam_crash_reproducer.c -o sssd_pam_crash_reproducer -lpam
4) Execute ./sssd_pam_crash_reproducer
5) Noticed the id for sssd_pam is changed:
4 S root 2620 2549 0 80 0 - 59732 ep_pol 17:01 ? 00:00:00 /usr/libexec/sssd/sssd_pam --uid 0 --gid 0 --debug-to-files
6) Also, following error message is noticed under /var/log/messages:
Oct 12 17:01:08 <ipa-server> kernel: sssd_pam[2580]: segfault at 10 ip 00007f0f11409730 sp 00007ffc27d5e490 error 4 in sssd_pam[7f0f11400000+20000]
Oct 12 17:01:08 <ipa-server> sssd[pam]: Starting up
Scenario B) For sssd-1.13.0-39.el7.x86_64, (On the same system, upgraded the sssd to latest version and Used this to verify fix for the issue)
observations:
1) Notice the sssd_pam process id, using ps -elf | grep sssd
(In my case)
4 S root 2702 2698 0 80 0 - 59760 ep_pol 17:12 ? 00:00:00 /usr/libexec/sssd/sssd_pam --uid 0 --gid 0 --debug-to-files
2) Now run the GCC compiler for the attached C program
gcc sssd_pam_crash_reproducer.c -o sssd_pam_crash_reproducer -lpam
3) Execute ./sssd_pam_crash_reproducer, following message is returned which is expected. (As per discussion with dev Team)
testing pam_authenticate
pam_authenticate: Insufficient credentials to access authentication data
4) Noticed the id for sssd_pam is NOT changed:
4 S root 2702 2698 0 80 0 - 59760 ep_pol 17:12 ? 00:00:00 /usr/libexec/sssd/sssd_pam --uid 0 --gid 0 --debug-to-files
5) Also, NO error message is noticed under /var/log/messages:
Thus on the basis of above observations in Scenario A) and Scenario B), marking the status of bug as "VERIFIED".
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://rhn.redhat.com/errata/RHSA-2015-2355.html