Date: Sat, 26 Oct 2013 14:33:37 GMT From: Mats Erik Andersson <bsd@gisladisker.se> To: freebsd-gnats-submit@FreeBSD.org Subject: bin/183336: rsh: Blocking stdin and server Message-ID: <201310261433.r9QEXbDW096784@oldred.freebsd.org> Resent-Message-ID: <201310261440.r9QEe0RM066809@freefall.freebsd.org>
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>Number: 183336 >Category: bin >Synopsis: rsh: Blocking stdin and server >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sat Oct 26 14:40:00 UTC 2013 >Closed-Date: >Last-Modified: >Originator: Mats Erik Andersson >Release: 9.1-RELEASE >Organization: >Environment: 9.1-RELEASE-p7 i386 >Description: The client binary rsh(1) is reacting erroneously on SIGPIPE. This is present since legacy time. The problem is that rsh(1) will, except when called using the switch "-n", be using a forked child process. When the parent process receives a signal SIGPIPE this parent process will immediately abort, and will never send a shutdown signal to the child process. This situation typically arises when rsh(1) is part of a command line pipeline, where one member fails. >How-To-Repeat: The use cases $ rsh localhost cat /etc/motd | false $ rsh localhost date | true will leave a child process still running, and will in turn keep the server process running indefinitely and will also steal stdin from the login session. >Fix: The problem is that the legacy code never installs a signal handler for SIGPIPE in the function talk(), but only later kills the client process in main(). >From the fact that the default handler for SIGPIPE is process abortion, the whole problem arises. Since I personally resolved this issue in a GNU project based on BSD legacy code for rsh(1), I regretfully cannot produce a patch for the fear of poluting you code base away from its present license, but the above mechanism is the culprit of this annoying issue. >Release-Note: >Audit-Trail: >Unformatted:
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