Comment 0 for bug 1771805

[Impact]

When SSSD tries to renew the machine password, a write_to_child_fd is open but never closed, leaking a descriptor per request until it hits the limit and SSSD stops.

[Test Case]

1. With an AD deployed, and having the machine registered, include the following option in sssd.conf:

# This option should only be used to test the machine account renewal task. The option expect 2 integers seperated by a colon (':'). The first integer defines the interval in
# seconds how often the task is run. The second specifies the inital timeout in seconds before the task is run for the first time after startup.
# Default: 86400:750 (24h and 15m)
ad_machine_account_password_renewal_opts = 5:5

2. Restart the service and monitor the use of descriptors:

root@sssd-xenial:/home/ubuntu# while true; do ll /proc/$(pidof sssd_be)/fd | wc -l; sleep 60; done
38
50
62
74
86
98
110
122
134
146
158
170
182
194
206
217
229
^C

[Other info]

The bug is reported and fixed upstream: https://pagure.io/SSSD/sssd/issue/3017
Trusty is not affected (feat not implemented) and A/B/C already include the fix