Apparently, IF_UNICAST_IF does not influence the routing decisions done
during connect(). But SO_BINDTODEVICE/SO_BINDTOINDEX does, which however
brings a lot of other semantics with it, we are not so interested in
(i.e. it doesn't not allow packets from any other iface to us, even if
routing otherwise allows it).
Hence, let's bind to the ifindex immediately before the connect() and
unbind right after again, so that we get the semantics we want, but not
the ones we don't.
Fixes: #11935
Replaces: #12004
This is mostly cosmetic, but let's reorder the destructors so that
we do the final sd_notify() call before we run the destructor for
the manager object.
If a daemon is not started as root, most likely it also can't create its
directory and let's not try to resolve the user in that case either.
Create /run/systemd/netif/lldp with tmpfiles.d like other netif directories.
This is also very helpful for preparing a RootImage for the daemons as NSS crud
is not needed.
In all three cases, sd_event_loop() will return the exit code anyway.
If sd_event_loop() returns negative, failure is logged and results in an
immediate return. Otherwise, we don't care if sd_event_loop() returns 0
or positive, because the return value feeds into DEFINE_MAIN_FUNCTION(), which
doesn't make the distinction.
`systemd-resolved.service` runs as `User=systemd-resolved`, and uses certain
Capabilit{y,ies} magic. By my understanding, this means it is started with a
number of "privileges". Indeed, `capabilities(7)` explains
> Linux divides the privileges traditionally
> associated with superuser into distinct units, known as capabilities,
> which can be independently enabled and disabled."
This situation appears to contradict our current code comment which said
> If we are not running as root we assume all privileges are already dropped.
This appears to be a confusion in the comment only. The rest of the code
tells a much clearer story. (Don't ask me if the story is correct.
`capabilities(7)` scares me). Let's tweak the comment to make it consistent
and avoid worrying readers about this.
Let's fold get_user_creds_clean() into get_user_creds(), and introduce a
flags argument for it to select "clean" behaviour. This flags parameter
also learns to other new flags:
- USER_CREDS_SYNTHESIZE_FALLBACK: in this mode the user records for
root/nobody are only synthesized as fallback. Normally, the synthesized
records take precedence over what is in the user database. With this
flag set this is reversed, and the user database takes precedence, and
the synthesized records are only used if they are missing there. This
flag should be set in cases where doing NSS is deemed safe, and where
there's interest in knowing the correct shell, for example if the
admin changed root's shell to zsh or suchlike.
- USER_CREDS_ALLOW_MISSING: if set, and a UID/GID is specified by
numeric value, and there's no user/group record for it accept it
anyway. This allows us to fix#9767
This then also ports all users to set the most appropriate flags.
Fixes: #9767
[zj: remove one isempty() call]
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
When we are attempting to create directory somewhere in the bowels of /var/lib
and get an error that it already exists, it can be quite hard to diagnose what
is wrong (especially for a user who is not aware that the directory must have
the specified owner, and permissions not looser than what was requested). Let's
print a warning in most cases. A warning is appropriate, because such state is
usually a sign of borked installation and needs to be resolved by the adminstrator.
$ build/test-fs-util
Path "/tmp/test-readlink_and_make_absolute" already exists and is not a directory, refusing.
(or)
Directory "/tmp/test-readlink_and_make_absolute" already exists, but has mode 0775 that is too permissive (0755 was requested), refusing.
(or)
Directory "/tmp/test-readlink_and_make_absolute" already exists, but is owned by 1001:1000 (1000:1000 was requested), refusing.
Assertion 'mkdir_safe(tempdir, 0755, getuid(), getgid(), MKDIR_WARN_MODE) >= 0' failed at ../src/test/test-fs-util.c:320, function test_readlink_and_make_absolute(). Aborting.
No functional change except for the new log lines.
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
This adds "systemd-resolve --reset-server-features" for explicitly
forgetting what we learnt. This might be useful for debugging
purposes, and to force systemd-resolved to restart its learning logic
for all DNS servers.
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.
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
The files are named too generically, so that they might conflict with
the upstream project headers. Hence, let's add a "-util" suffix, to
clarify that this are just our utility headers and not any official
upstream headers.
This ports a lot of manual code over to sigprocmask_many() and friends.
Also, we now consistly check for sigprocmask() failures with
assert_se(), since the call cannot realistically fail unless there's a
programming error.
Also encloses a few sd_event_add_signal() calls with (void) when we
ignore the return values for it knowingly.
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.
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().
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.
