This also moves log message generation into manager_write_resolv_conf(), so
that it is shorter to invoke the function, given that we have to invoke it at a
couple of additional places now.
Fixes: #3225
Make sure we can parse DNS server addresses that use the "zone id" syntax for
local link addresses, i.e. "fe80::c256:27ff:febb:12f%wlp3s0", when reading
/etc/resolv.conf.
Also make sure we spit this out correctly again when writing /etc/resolv.conf
and via the bus.
Fixes: #3359
When the buffer is allocated on the stack we do not have to check for
failure everywhere. This is especially useful in debug statements, because
we can put dns_resource_key_to_string() call in the debug statement, and
we do not need a seperate if (log_level >= LOG_DEBUG) for the conversion.
dns_resource_key_to_string() is changed not to provide any whitespace
padding. Most callers were stripping the whitespace with strstrip(),
and it did not look to well anyway. systemd-resolve output is not column
aligned anymore.
The result of the conversion is not stored in DnsTransaction object
anymore. It is used only for debugging, so it seems fine to generate it
when needed.
Various debug statements are extended to provide more information.
Let's make sure DNSSEC gets more testing, by defaulting DNSSEC to
"allow-downgrade" mode. Since distros should probably not ship DNSSEC enabled
by default add a configure switch to disable this again.
DNSSEC in "allow-downgrade" mode should mostly work without affecting user
experience. There's one exception: some captive portal systems rewrite DNS in
order to redirect HTTP traffic to the captive portal. If these systems
implement DNS servers that are otherwise DNSSEC-capable (which in fact is
pretty unlikely, but still...), then this will result in the captive portal
being inaccessible. To fix this support in NetworkManager (or any other network
management solution that does captive portal detection) is required, which
simply turns off DNSSEC during the captive portal detection, and resets it back
to the default (i.e. on) after captive portal authentication is complete.
Previously, if a hostanem is resolved with AF_UNSPEC specified, this would be used as indication to resolve both an
AF_INET and an AF_INET6 address. With this change this logic is altered: an AF_INET address is only resolved if there's
actually a routable IPv4 address on the specific interface, and similar an AF_INET6 address is only resolved if there's
a routable IPv6 address. With this in place, it's ensured that the returned data is actually connectable by
applications. This logic mimics glibc's resolver behaviour.
Note that if the client asks explicitly for AF_INET or AF_INET6 it will get what it asked for.
This also simplifies the logic how it is determined whether a specific lookup shall take place on a scope.
Specifically, the checks with dns_scope_good_key() are now moved out of the transaction code and into the query code,
so that we don't even create a transaction object on a specific scope if we cannot execute the resolution on it anyway.
Lets make sure we always take notice of network changes before answering client requests.
This way, calls like SetLinkDNS() become race-free as the specified interface index is guarantee to have been processed
if it exists before we make changes to it.
Not only report whether the server actually supports DNSSEC, but also first check whether DNSSEC is actually enabled
for it in our local configuration.
Also, export a per-link DNSSECSupported property in addition to the existing manager-wide property.
networkd previously knew an enum "ResolveSupport" for configuring
per-interface LLMNR support, resolved had a similar enum just called
"Support", with the same value and similar pasers.
Unify this, call the enum ResolveSupport, and port both daemons to it.
In a couple of cases we maintain configuration settings that know an on
and off state, like a boolean, plus some additional states. We generally
parse them as booleans first, and if that fails check for specific
additional values.
This adds a generalized set of macros for parsing such settings, and
ports one use in resolved and another in networkd over to it.
When doing DNSSEC lookups we need to know one or more DS or DNSKEY RRs
as trust anchors to validate lookups. With this change we add a
compiled-in trust anchor database, serving the root DS key as of today,
retrieved from:
https://data.iana.org/root-anchors/root-anchors.xml
The interface is kept generic, so that additional DS or DNSKEY RRs may
be served via the same interface, for example by provisioning them
locally in external files to support "islands" of security.
The trust anchor database becomes the fourth source of RRs we maintain,
besides, the network, the local cache, and the local zone.
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
The new dns_label_escape() call now operates on a buffer passed in,
similar to dns_label_unescape(). This should make decoding a bit faster,
and nicer.
This copies concepts we introduced for the DnsSearchDomain stuff, and
reworks the operations on lists of dns servers to be reusable and
generic for use both with the Link and the Manager object.
With this change, we add a new object to resolved, "DnsSearchDomain="
which wraps a search domain. This is then used to introduce a global
search domain list, in addition to the existing per-link search domain
list which is reword to make use of this new object too.
This is preparation for implement proper unicast DNS search domain
support.
Previously, there was a chance of memory corruption, because when
switching to the next DNS server we didn't care whether they linked list
of DNS servers was still valid.
Clean up lifecycle of the dns server logic:
- When a DnsServer object is still in the linked list of DnsServers for
a link or the manager, indicate so with a "linked" boolean field, and
never follow the linked list if that boolean is not set.
- When picking a DnsServer to use for a link ot manager, always
explicitly take a reference.
This also rearranges some logic, to make the tracking of dns servers by
link and globally more alike.
Let's use the same parser when parsing dns server information from
/etc/resolv.conf and our native configuration file.
Also, move all code that manages lists of dns servers to a single place.
resolved-dns-server.c
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
Turns this:
r = -errno;
log_error_errno(errno, "foo");
into this:
r = log_error_errno(errno, "foo");
and this:
r = log_error_errno(errno, "foo");
return r;
into this:
return log_error_errno(errno, "foo");
With this change we'll now also generate synthesized RRs for the local
LLMNR hostname (first label of system hostname), the local mDNS hostname
(first label of system hostname suffixed with .local), the "gateway"
hostname and all the reverse PTRs. This hence takes over part of what
nss-myhostname already implemented.
Local hostnames resolve to the set of local IP addresses. Since the
addresses are possibly on different interfaces it is necessary to change
the internal DnsAnswer object to track per-RR interface indexes, and to
change the bus API to always return the interface per-address rather than
per-reply. This change also patches the existing clients for resolved
accordingly (nss-resolve + systemd-resolve-host).
This also changes the routing logic for queries slightly: we now ensure
that the local hostname is never resolved via LLMNR, thus making it
trustable on the local system.
The following functions return immediately if a null pointer was passed.
* calendar_spec_free
* link_address_free
* manager_free
* sd_bus_unref
* sd_journal_close
* udev_monitor_unref
* udev_unref
It is therefore not needed that a function caller repeats a corresponding check.
This issue was fixed by using the software Coccinelle 1.0.1.
As we have connect()ed to the desired DNS server, we no longer need to pass
control messages manually when sending packets. Simplify the logic accordingly.
We used to have one global socket, use one per transaction instead. This
has the side-effect of giving us a random UDP port per transaction, and
hence increasing the entropy and making cache poisoining significantly
harder to achieve.
We still reuse the same port number for packets belonging to the same
transaction (resent packets).
This patch removes includes that are not used. The removals were found with
include-what-you-use which checks if any of the symbols from a header is
in use.
include-what-you-use automatically does this and it makes finding
unnecessary harder to spot. The only content of poll.h is a include
of sys/poll.h so should be harmless.
Previously we tried to stick to a DNS server as long as it is available.
When /etc/resolv.conf changed, and the old DNS server we used was still
in there we'd continue to use it, even if it was at the end of the list.
With this change we'll now always start with the first DNS server in the
list again.
Rationale: certain network managing implementations (notably
NetworkManager) when connected to a VPN place both the VPN DNS server as
well as the local DNS server in /etc/resolv.conf. If we used the local
one before we would thus continue to use the local one, making VPN names
unresolvable. NetworkManager really should be fixed to only place the
VPN DNS servers in the file, but with this commit things are at least
similarly bad as they used to be...
If the format string contains %m, clearly errno must have a meaningful
value, so we might as well use log_*_errno to have ERRNO= logged.
Using:
find . -name '*.[ch]' | xargs sed -r -i -e \
's/log_(debug|info|notice|warning|error|emergency)\((".*%m.*")/log_\1_errno(errno, \2/'
Plus some whitespace, linewrap, and indent adjustments.
As a followup to 086891e5c1 "log: add an "error" parameter to all
low-level logging calls and intrdouce log_error_errno() as log calls
that take error numbers", use sed to convert the simple cases to use
the new macros:
find . -name '*.[ch]' | xargs sed -r -i -e \
's/log_(debug|info|notice|warning|error|emergency)\("(.*)%s"(.*), strerror\(-([a-zA-Z_]+)\)\);/log_\1_errno(-\4, "\2%m"\3);/'
Multi-line log_*() invocations are not covered.
And we also should add log_unit_*_errno().
We can simplify our code quite a bit if we explicitly check for the
ifindex being 1 on Linux as a loopback check. Apparently, this is
hardcoded on Linux on the kernel, and effectively exported to userspace
via rtnl and such, hence we should be able to rely on it.
Under an SELinux system, we want the file that is created to
have a proper context, different from the default for files in /run.
This is so that the policy can give access to almost everyone to
this file.
It is redundant to store 'hash' and 'compare' function pointers in
struct Hashmap separately. The functions always comprise a pair.
Store a single pointer to struct hash_ops instead.
systemd keeps hundreds of hashmaps, so this saves a little bit of
memory.
The MAXSIZE() macro takes two types and returns the size of the larger
one. It is much simpler to use than MAX(sizeof(A), sizeof(B)) and also
avoids any compiler-extensions, unlike CONST_MAX() and MAX() (which are
needed to avoid evaluating arguments more than once). This was suggested
by Daniele Nicolodi <daniele@grinta.net>.
Also make resolved use this macro instead of CONST_MAX(). This enhances
readability quite a bit.
We now maintain two lists of DNS servers: system servers and fallback
servers.
system servers are used in combination with any per-link servers.
fallback servers are only used if there are no system servers or
per-link servers configured.
The system server list is supposed to be populated from a foreign tool's
/etc/resolv.conf (not implemented yet).
Also adds a configuration switch for LLMNR, that allows configuring
whether LLMNR shall be used simply for resolving or also for responding.
String which ended in an unfinished quote were accepted, potentially
with bad memory accesses.
Reject anything which ends in a unfished quote, or contains
non-whitespace characters right after the closing quote.
_FOREACH_WORD now returns the invalid character in *state. But this return
value is not checked anywhere yet.
Also, make 'word' and 'state' variables const pointers, and rename 'w'
to 'word' in various places. Things are easier to read if the same name
is used consistently.
mbiebl_> am I correct that something like this doesn't work
mbiebl_> ExecStart=/usr/bin/encfs --extpass='/bin/systemd-ask-passwd "Unlock EncFS"'
mbiebl_> systemd seems to strip of the quotes
mbiebl_> systemctl status shows
mbiebl_> ExecStart=/usr/bin/encfs --extpass='/bin/systemd-ask-password Unlock EncFS $RootDir $MountPoint
mbiebl_> which is pretty weird
