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Description of problem: Login attempts via ssh as remote user (AD or IPA) often fails with: # ssh <user>@<domain>@localhost <user>@<domain>@localhost's password: Write failed: Broken pipe The problem was observed on the latest RHEL-7.2 test composes; not sure the issue is caused directly by sssd, but I'm clueless (sssd debugs will be attached). The problems were newer seen on RHEL-7.1 machines. The issue appears only time to time, usually after sssd restart. When join to AD is via winbind the problem does not appear. Version-Release number of selected component (if applicable): sssd-1.13.0-26.el7 openssh-6.6.1p1-18.el7 realmd-0.16.1-3.el7 pam-1.1.8-12.el7_1.1 How reproducible: ~50% Steps to Reproduce: 1. join to AD with realmd 2. try to login via ssh 3. if login succeed try to restart sssd and/or join again Actual results: ssh often fails Expected results: ssh is reliable Additional info:
Both authentication and access control part look good in the SSSD logs. Can you add pam and nss responder logs and sshd logs with a high debug level as welll?
It would be also good to attach /var/log/secure
Created attachment 1072168 [details] strace of sshd child Thank you for providing the test environment, it was very useful. I used strace to see what sshd is doing and found a "corrupted double-linked list" error in one of the sshd child processes. Currently I cannot make sense of the output so I attached the file for others to check.
(In reply to Sumit Bose from comment #9) > Created attachment 1072168 [details] > strace of sshd child > > Thank you for providing the test environment, it was very useful. I used > strace to see what sshd is doing and found a "corrupted double-linked list" > error in one of the sshd child processes. > > Currently I cannot make sense of the output so I attached the file for > others to check. Thanks a lot for looking into this. Do you think it's time to reassign this bugzilla to sshd, then?
We have tracked this down to a security bug, bug 1262914 in glibc.
We have confirmed that this issue is indeed caused by glibc bug 1262914, based on further analysis of the issue. After installing a glibc scratch build with the upstream fix applied, the original sssd issue is no longer reproducible. I'm closing this as a duplicate of the (internal) glibc 7.2 bug for this issue. *** This bug has been marked as a duplicate of bug 1263134 ***