Bug 687

Created attachment 444 [details]
patch: properly restore SIGPIPE's action

Hello. Slackware 14.1 recently bumped its sudo version from 1.8.6p8 to 1.8.12 to address CVE-2014-9680.

After the upgrade, gaining root via 'sudo -i' and running makewhatis causes gzip (called by makewhatis) to throw a bunch of EPIPEs (see original report: https://tinyurl.com/mmmdrcx).

Gzip was not receiving SIGPIPE and after some digging I discovered the source of the problem is a long-standing bug in sudo's tgetpass: SIGPIPE's signal action is not properly restored.

Sudo 1.8.6p8 also has the bug but in that version a more liberal restore_signals restores the action before exec.

Attached patch against HEAD@20150301 fixes the bug.

To repro, run this script after switching to root with "sudo -i" (make sure to traverse the password-getting code):

-----------------
#!/bin/bash
trap "{ echo Success ; exit 0; }" SIGPIPE
kill -s PIPE "$$"
echo "Failure"
exit 1
-----------------

--mancha