Red Hat Bugzilla – Bug 1452034
when the /etc/hosts file has a line longer than 1028 characters getent ahostsv4 and ahostsv6 will stop working.
Last modified: 2018-04-10 10:00:11 EDT
+++ This bug was initially created as a clone of Bug #1452032 +++ Description of problem: when the /etc/hosts file has a line longer than 1028 characters getent ahostsv4 and ahostsv6 will stop working for hostsnames present in /etc/hosts. This happens even if the line is a comment. Version-Release number of selected component (if applicable): Tested in RHEL 6.9 and RHEL 7.3 glibc-2.17-157 glibc-2.12-1 How reproducible: Always Steps to Reproduce: With this oneliner you can see how it stops resolving after the line reaches 1028 characters, even if it's commented. echo -n '#' >>/etc/hosts ; for i in $(seq 1 1030); do echo -n "$i - "; echo -n 'a' >>/etc/hosts ; getent ahostsv4 `hostname -f`; done Actual results: It stops working after 1028 characters. Expected results: It continues working and at least ignores the commented line Additional info: --- Additional comment from Red Hat Bugzilla Rules Engine on 2017-05-18 04:12:24 EDT --- Since this bug report was entered in Red Hat Bugzilla, the release flag has been set to ? to ensure that it is properly evaluated for this release.
The core issue is that getaddrinfo looks at h_errno even if nss_files returns NSS_STATUS_SUCCESS. The reproducer triggers an internal failure within nss_files, which overwrites h_errno, although the nss_files succeeds eventually. Upstream, we will fix this by changing getaddrinfo, but *how* is not completely clear to me yet. Downstream, we can either rebase getaddrinfo (more or less required to fix bug 168253), or patch nss_files not to leak the temporary h_errno value in this case.
Upstream patch posted: https://sourceware.org/ml/libc-alpha/2017-08/msg00292.html
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2018:0805