Bug 1648009
| Summary: | NetworkManager limits the search field of resolv.conf to 6 entries in _collect_resolv_conf_data() | |||
|---|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Kyle Walker <kwalker> | |
| Component: | NetworkManager | Assignee: | Thomas Haller <thaller> | |
| Status: | CLOSED ERRATA | QA Contact: | Desktop QE <desktop-qa-list> | |
| Severity: | medium | Docs Contact: | ||
| Priority: | medium | |||
| Version: | 7.6 | CC: | atragler, bgalvani, fgiudici, fpokryvk, fweimer, lrintel, ptalbert, rkhan, sukulkar, thaller | |
| Target Milestone: | rc | |||
| Target Release: | --- | |||
| Hardware: | Unspecified | |||
| OS: | Unspecified | |||
| Whiteboard: | ||||
| Fixed In Version: | NetworkManager-1.18.0-0.3.20190408git43d9187c14.el7 | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | ||
| Clone Of: | ||||
| : | 1649704 (view as bug list) | Environment: | ||
| Last Closed: | 2019-08-06 13:16:25 UTC | Type: | Bug | |
| Regression: | --- | Mount Type: | --- | |
| Documentation: | --- | CRM: | ||
| Verified Versions: | Category: | --- | ||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | ||
| Cloudforms Team: | --- | Target Upstream Version: | ||
| Embargoed: | ||||
| Bug Depends On: | ||||
| Bug Blocks: | 1649704 | |||
Filed an upstream issue as well:
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/issues/80
- Kyle Walker
Patch suggestion accepted upstream:
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/issues/80
Additional patch added to avoid search entry being truncated on legacy systems. Full patch set upstream is:
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/commit/49c11a44e4e901752a81e3942efca64448fa7c53
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/commit/3f2cc579e7627f45a77f835ba2f402e1b5c600b5
- Kyle Walker
fixed upstream. As a workaround the NetworkManager global-dns 'searches=' option is not limited to 6 search domains. WORKAROUND ========== Create a file in /etc/NetworkManager/conf.d/*.conf and add these entries: [main] dns=default [global-dns] searches=one.example.com two.example.com three.example.com four.example.com five.example.com six.example.com seven.example.com eight.example.com [global-dns-domain-*] servers=xxx.xxx.xxx.xxx 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/RHBA-2019:2302 |
Description of problem: The _collect_resolv_conf_data() function limits the number of search entries to 6 within the following code snippet. Taken from the 1.10.2-16 source revision: /* Per 'man resolv.conf', the search list is limited to 6 domains * totalling 256 characters. */ num = MIN (rc.searches->len, 6u); for (i = 0, len = 0; i < num; i++) { len += strlen (rc.searches->pdata[i]) + 1; /* +1 for spaces */ if (len > 256) break; } g_ptr_array_set_size (rc.searches, i); This is no longer the limit for later RHEL releases. The limit was removed with the efforts in RHBZ677316 [^1] and released in upstream glibc-2.26 [^2]. Version-Release number of selected component (if applicable): # rpm -q NetworkManager NetworkManager-1.10.2-16.el7_5.x86_64 How reproducible: Easily Steps to Reproduce: 1. Set an interface to a ipv4.dns-search entry greater than 6 # nmcli con modify System\ eth0 ipv4.dns-search $(echo {a..g}.redhat.com, | sed -e 's/ //g' -e 's/,$//g') 2. Verify the ipv4.dns-search field includes more than 6 entries # nmcli con show System\ eth0 | grep ipv4.dns-search ipv4.dns-search: a.redhat.com,b.redhat.com,c.redhat.com,d.redhat.com,e.redhat.com,f.redhat.com,g.redhat.com 3. Issue an "nmcli con up <interface>" and verify that the /etc/resolv.conf has more than 6 entries # nmcli con up System\ eth0 # grep search /etc/resolv.conf Actual results: search a.redhat.com b.redhat.com c.redhat.com d.redhat.com e.redhat.com f.redhat.com Expected results: search a.redhat.com b.redhat.com c.redhat.com d.redhat.com e.redhat.com f.redhat.com g.redhat.com Additional info: The problem is not seen when disabling NetworkManager and falling back to the underlying network initscripts. # systemctl stop NetworkManager && systemctl restart network && grep search /etc/resolv.conf search a.redhat.com b.redhat.com c.redhat.com d.redhat.com e.redhat.com f.redhat.com g.redhat.com The problem is also present with the latest available upstream NetworkManager revision [^3]. [^1]: https://bugzilla.redhat.com/show_bug.cgi?id=677316 [^2]: https://sourceware.org/ml/libc-alpha/2017-08/msg00010.html [^3]: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/blob/master/src/dns/nm-dns-manager.c#L1132