We'd copy /etc/nsswitch.conf, /etc/pam.d/, and /etc/issue (*) on every
tmpfiles --create run. I think we should only do this at boot, so if
people install systemd.rpm in a larger transaction and want to create those
files at a later step, we don't interfere with that.
(Stuff like /etc/os-release and /etc/mtab is not really configurable,
we might as was create it uncondtionally.)
(Seemingly, the alternative approach might be to not call
systemd-tmpfiles --create in systemd.rpm %post. But this wouldn't have much
effect, because various packages call it anyway, and our
%tmpfiles_create_package macro does too. So we need to change the
configuration instead.)
(*) We don't provide /usr/share/factory/issue, so normally this fails, but
somebody else might provide that file, so it seems useful to keep the
C line.
If the symlink is not present, UTC is the default. There *is* a slight
advantage to it: humans might expect it to be present and look in /etc.
But it might interfere with post-install scripts and it doesn't serve
any technical purpose. Let's not create it. Fixes#13183.
Booting up an image with --volatile=yes otherwise looks so naked, so
let's include this file in the default factory too. It's common and
simple and should be safe to ship.
This creates a second private resolve.conf file which lists the stub resolver
and the resolved acquired search domains.
This runtime file should be used as a symlink target for /etc/resolv.conf such
that non-nss based applications can resolve search domains.
Fixes: #7009
The configuration option was called -Dresolve, but the internal define
was …RESOLVED. This options governs more than just resolved itself, so
let's settle on the version without "d".
In order to improve compatibility with local clients that speak DNS directly
(and do not use NSS or our bus API) listen locally on 127.0.0.53:53 and process
any queries made that way.
Note that resolved does not implement a full DNS server on this port, but
simply enough to allow normal, local clients to resolve RRs through resolved.
Specifically it does not implement queries without the RD bit set (these are
requests where recursive lookups are explicitly disabled), and neither queries
with DNSSEC DO set in combination with DNSSEC CD (i.e. DNSSEC lookups with
validation turned off). It also refuses zone transfers and obsolete RR types.
All lookups done this way will be rejected with a clean error code, so that the
client side can repeat the query with a reduced feature set.
The code will set the DNSSEC AD flag however, depending on whether the data
resolved has been validated (or comes from a local, trusted source).
Lookups made via this mechanisms are propagated to LLMNR and mDNS as necessary,
but this is only partially useful as DNS packets cannot carry IP scope data
(i.e. the ifindex), and hence link-local addresses returned cannot be used
properly (and given that LLMNR/mDNS are mostly about link-local communication
this is quite a limitation). Also, given that DNS tends to use IDNA for
non-ASCII names, while LLMNR/mDNS uses UTF-8 lookups cannot be mapped 1:1.
In general this should improve compatibility with clients bypassing NSS but
it is highly recommended for clients to instead use NSS or our native bus API.
This patch also beefs up the DnsStream logic, as it reuses the code for local
TCP listening. DnsStream now provides proper reference counting for its
objects.
In order to avoid feedback loops resolved will no silently ignore 127.0.0.53
specified as DNS server when reading configuration.
resolved listens on 127.0.0.53:53 instead of 127.0.0.1:53 in order to leave
the latter free for local, external DNS servers or forwarders.
This also changes the "etc.conf" tmpfiles snippet to create a symlink from
/etc/resolv.conf to /usr/lib/systemd/resolv.conf by default, thus making this
stub the default mode of operation if /etc is not populated.
/etc/mtab should be labeled as "_", even though systemd has its own
smack label using '--with-smack-run-label' configuration. This is mainly
because all processes could read that file and the origin of this file
(i.e. /proc/mounts) is labeled as "_". This labels /etc/mtab as "_" when
'--with-smack-run-label' is enabled.
We will create the symlink on boot as a fallback to provide name
resolution. But if the symlink was removed afterwards, it most likely
should not be recreated. Creating it only on boot also solves the
issue where it would be created prematurely during installation,
before the system was actually booted.
https://bugzilla.redhat.com/show_bug.cgi?id=1197204
This patch removes unnecessary blank line in
/usr/lib/tmpfiles.d/etc.conf when configured with "--disable-resolved".
(i.e. ENABLE_RESOLVED is not defined)
Zbigniew Jędrzejewski-Szmek