Red Hat Bugzilla – Bug 1005202
running "ausearch -m avc,user_avc -ts today" over ssh gets stuck
Last modified: 2015-04-06 23:10:55 EDT
Description of problem: running on RHEL 6.4/6.5 ssh 10.34.63.19 ausearch -m avc,user_avc -ts today gets stuck while running the command on the node returns result immediately ausearch -m avc,user_avc -ts today <no matches> Version-Release number of selected component (if applicable): rpm -qa audit audit-2.2-2.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. run ssh $IP ausearch -m avc,user_avc -ts today Actual results: command gets stuck Expected results: command returns valid response Additional info: this BZ was raised based on bug 1005066 , there is some more information which might be useful
I have no idea why it would get stuck. It uses printf to write out the findings. Maybe strace would help locate the problem?
Created attachment 795507 [details] strace
Thanks for the strace. It shows the client end waiting for something. What I am curious about is what ausearch is doing. If this is still reproducable, could you get an strace of ausearch? Thanks.
Created attachment 798111 [details] strace_ausearch
If it may help, ssh -t seems to solve the issue. In https://bugzilla.redhat.com/show_bug.cgi?id=1010472 Derrick Ornelas says: The issue appears to be that the ausearch command requires a controlling TTY(pty), and hangs indefinitely without access to one.
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unable to address this request at this time. Red Hat invites you to ask your support representative to propose this request, if appropriate, in the next release of Red Hat Enterprise Linux.
Florian pointed out in bug 1032706 that this is actually expected behaviour when stdin is a pipe: > ausearch doesn't need a TTY, it alters behavior if the input is a pipe. > This is documented behavior, mentioned in the manpage: > > --input-logs > Use the log file location from auditd.conf as input for search‐ > ing. This is needed if you are using ausearch from a cron job. And reading the log from stdin is mentioned in the opening paragraph of the man pages for ausearch and aureport (which has the same logic): "The ausearch utility can also take input from stdin as long as the input is the raw log data." Seems this is NOTABUG.