Previously, the unreachable code paths would have to be tagged with:
INSIST(0);
ISC_UNREACHABLE();
There was also older parts of the code that used comment annotation:
/* NOTREACHED */
Unify the handling of unreachable code paths to just use:
UNREACHABLE();
The UNREACHABLE() macro now asserts when reached and also uses
__builtin_unreachable(); when such builtin is available in the compiler.
(cherry picked from commit 584f0d7a7e)
Gcc 7+ and Clang 10+ have implemented __attribute__((fallthrough)) which
is explicit version of the /* FALLTHROUGH */ comment we are currently
using.
Add and apply FALLTHROUGH macro that uses the attribute if available,
but does nothing on older compilers.
In one case (lib/dns/zone.c), using the macro revealed that we were
using the /* FALLTHROUGH */ comment in wrong place, remove that comment.
(cherry picked from commit fe7ce629f4)
For each algorithm there must be a key performing the KSK and
ZSK rolls. After reading the keys from named.conf check that
each algorithm present has both rolls. CSK implicitly has both
rolls.
(cherry picked from commit 9bcf45f4ce)
the "zone" clause can be documented using, for instance,
`cfg_test --zonegrammar primary", which prints only
options that are valid in primary zones. this was not
the method being used when generating the named.conf
man page; instead, "zone" was documented with all possible
options, and no zone types at all.
this commit removes "zone" from the generic documentation
and adds include statements in named.conf.rst so that
correct zone grammars will be included in the man page.
(cherry picked from commit 4ca74eee49)
we now document zone type as either "primary" or "secondary",
omitting the old terms (though they are still accepted).
(cherry picked from commit 0bde07261b)
"masters" and "default-masters" are now flagged so they will
not be included in the named.conf man page, despite being
accepted as valid options by the parser for backward
compatibiility.
(cherry picked from commit 0e57fc160e)
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
A kasp structure was not detached when looking to see if there
was an existing kasp structure with the same name, causing memory
to be leaked. Fixed by calling dns_kasp_detach() to release the
reference.
It's unclear if we are going to keep it or not, so let's mark it as
deprecated for a good measure. It's easier to un-deprecate it than the
other way around.
A number of DNS implementation produce NSEC records with bad type
maps that don't contain types that exist at the name leading to
NODATA responses being synthesize instead of the records in the
zone. NSEC records with these bad type maps often have the NSEC
NSEC field set to '\000.QNAME'. We look for the first label of
this pattern.
e.g.
example.com NSEC \000.example.com SOA NS NSEC RRSIG
example.com RRRSIG NSEC ...
example.com SOA ...
example.com RRRSIG SOA ...
example.com NS ...
example.com RRRSIG NS ...
example.com A ...
example.com RRRSIG A ...
A is missing from the type map.
This introduces a temporary option 'reject-000-label' to control
this behaviour.
This sets as many server options as possible at once to detect
cut-and-paste bugs when implementing new server options in peer.c.
Most of the accessor functions are similar and it is easy to miss
updating a macro name or structure element name when adding new
accessor functions.
checkconf/setup.sh is there to minimise the difference to branches
with optional server options where the list is updated at runtime.
'server <prefix> { broken-nsec yes; };' can now be used to stop
NSEC records from negative responses from servers in the given
prefix being cached and hence available to synth-from-dnssec.
This commit completes the integration of the new, extended ACL syntax
featuring 'port' and 'transport' options.
The runtime presentation and ACL loading code are extended to allow
the syntax to be used beyond the 'allow-transfer' option (e.g. in
'acl' definitions and other 'allow-*' options) and can be used to
ultimately extend the ACL support with transport-only
ACLs (e.g. 'transport-acl tls-acl port 853 transport tls'). But, due
to fundamental nature of such a change, it has not been completed as a
part of 9.17.X release series due to it being close to 9.18 stable
release status. That means that we do not have enough time to fully
test it.
The complete integration is planned as a part of 9.19.X release
series.
The code was manually verified to work as expected by temporarily
enabling the extended syntax for 'acl' statements and 'allow-query'
options, including ACL merging, negated ACLs.
This commit extends ACL syntax handling code with 'port' and
'transport' options. Currently, the extended syntax is available only
for allow-transfer options.
This commit disables the unused 'tls' clause options. For these some
backing code exists, but their values are not really used anywhere,
nor there are sufficient syntax tests for them.
These options are only disabled temporarily, until TLS certificate
verification gets implemented.
When using 'nsec3param' in 'dnssec-policy' and no specific parameters
are provided, default to zero additional iterations and no salt, as
recommended by draft-ietf-dnsop-nsec3-guidance.
The new rules compare the target name in PTR and SRV records against
the machine name embedded in the kerberos principal. This can be
used to further restrict what PTR and SRV records can be added or
deleted via dynamic updates if desired.
Unify the header guard style and replace the inconsistent include guards
with #pragma once.
The #pragma once is widely and very well supported in all compilers that
BIND 9 supports, and #pragma once was already in use in several new or
refactored headers.
Using simpler method will also allow us to automate header guard checks
as this is simpler to programatically check.
For reference, here are the reasons for the change taken from
Wikipedia[1]:
> In the C and C++ programming languages, #pragma once is a non-standard
> but widely supported preprocessor directive designed to cause the
> current source file to be included only once in a single compilation.
>
> Thus, #pragma once serves the same purpose as include guards, but with
> several advantages, including: less code, avoidance of name clashes,
> and sometimes improvement in compilation speed. On the other hand,
> #pragma once is not necessarily available in all compilers and its
> implementation is tricky and might not always be reliable.
1. https://en.wikipedia.org/wiki/Pragma_once
Replace most "master/slave" terminology in tests with the preferred
"primary/secondary", with the following exceptions:
- When testing the old syntax
- When master is used in master file and master file format terms
- When master is used in hostmaster or postmaster terms
- When master used in legacy domain names (for example in dig.batch)
- When there is no replacement (for example default-masters)
Remove the dynamic registration of result codes. Convert isc_result_t
from unsigned + #defines into 32-bit enum type in grand unified
<isc/result.h> header. Keep the existing values of the result codes
even at the expense of the description and identifier tables being
unnecessary large.
Additionally, add couple of:
switch (result) {
[...]
default:
break;
}
statements where compiler now complains about missing enum values in the
switch statement.
This commit adds the ability to enable or disable stateless TLS
session resumption tickets (see RFC5077). Having this ability is
twofold.
Firstly, these tickets are encrypted by the server, and the algorithm
might be weaker than the algorithm negotiated during the TLS session
establishment (it is in general the case for TLSv1.2, but the generic
principle applies to TLSv1.3 as well, despite it having better ciphers
for session tickets). Thus, they might compromise Perfect Forward
Secrecy.
Secondly, disabling it might be necessary if the same TLS key/cert
pair is supposed to be used by multiple servers to achieve, e.g., load
balancing because the session ticket by default gets generated in
runtime, while to achieve successful session resumption ability, in
this case, would have required using a shared key.
The proper alternative to having the ability to disable stateless TLS
session resumption tickets is to implement a proper session tickets
key rollover mechanism so that key rotation might be performed
often (e.g. once an hour) to not compromise forward secrecy while
retaining the associated performance benefits. That is much more work,
though. On the other hand, having the ability to disable session
tickets allows having a deployable configuration right now in the
cases when either forward secrecy is wanted or sharing the TLS
key/cert pair between multiple servers is needed (or both).
This commit adds support for enforcing the preference of server
ciphers over the client ones. This way, the server attains control
over the ciphers priority and, thus, can choose more strong cyphers
when a client prioritises less strong ciphers over the more strong
ones, which is beneficial when trying to achieve Perfect Forward
Secrecy.
This commit adds support for setting TLS cipher list string in the
format specified in the OpenSSL
documentation (https://www.openssl.org/docs/man1.1.1/man1/ciphers.html).
The syntax of the cipher list is verified so that specifying the wrong
string will prevent the configuration from being loaded.
This commit adds support for loading DH-parameters (Diffie-Hellman
parameters) via the new "dhparam-file" option within "tls" clause. In
particular, Diffie-Hellman parameters are needed to enable the range
of forward-secrecy enabled cyphers for TLSv1.2, which are getting
silently disabled otherwise.
This commit adds the ability to specify allowed TLS protocols versions
within the "tls" clause. If an unsupported TLS protocol version is
specified in a file, the configuration file will not pass
verification.
Also, this commit adds strict checks for "tls" clauses verification,
in particular:
- it ensures that loading configuration files containing duplicated
"tls" clauses is not allowed;
- it ensures that loading configuration files containing "tls" clauses
missing "cert-file" or "key-file" is not allowed;
- it ensures that loading configuration files containing "tls" clauses
named as "ephemeral" or "none" is not allowed.
"cache-file" was already documented as intended for testing
purposes only and not to be used, so we can remove it without
waiting. this commit marks the option as "ancient", and
removes all the documentation and implementing code, including
dns_cache_setfilename() and dns_cache_dump().
it also removes the documentation for the '-x cachefile`
parameter to named, which had already been removed, but the man
page was not updated at the time.
This commit fixes a regression introduced at
ea80bcc41c. Some options, which are
common to both DoH and DoT were mistakenly disabled for non-DoH
builds. That is a mistake, because DoH does not imply DoT and vice
versa. Not fixing this would make DoT functionality not accessible
without DoH.
This commit makes number of concurrent HTTP/2 streams per connection
configurable as a mean to fight DDoS attacks. As soon as the limit is
reached, BIND terminates the whole session.
The commit adds a global configuration
option (http-streams-per-connection) which can be overridden in an
http <name> {...} statement like follows:
http local-http-server {
...
streams-per-connection 100;
...
};
For now the default value is 100, which should be enough (e.g. NGINX
uses 128, but it is a full-featured WEB-server). When using lower
numbers (e.g. ~70), it is possible to hit the limit with
e.g. flamethrower.
This commit adds support for http-listener-clients global options as
well as ability to override the default in an HTTP server description,
like:
http local-http-server {
...
listener-clients 100;
...
};
This way we have ability to specify per-listener active connections
quota globally and then override it when required. This is exactly
what AT&T requested us: they wanted a functionality to specify quota
globally and then override it for specific IPs. This change
functionality makes such a configuration possible.
It makes sense: for example, one could have different quotas for
internal and external clients. Or, for example, one could use BIND's
internal ability to serve encrypted DoH with some sane quota value for
internal clients, while having un-encrypted DoH listener without quota
to put BIND behind a load balancer doing TLS offloading for external
clients.
Moreover, the code no more shares the quota with TCP, which makes
little sense anyway (see tcp-clients option), because of the nature of
interaction of DoH clients: they tend to keep idle opened connections
for longer periods of time, preventing the TCP and TLS client from
being served. Thus, the need to have a separate, generally larger,
quota for them.
Also, the change makes any option within "http <name> { ... };"
statement optional, making it easier to override only required default
options.
By default, the DoH connections are limited to 300 per listener. I
hope that it is a good initial guesstimate.
This commit adds the code (and some tests) which allows verifying
validity of HTTP paths both in incoming HTTP requests and in BIND's
configuration file.
This commit adds two new autoconf options `--enable-doh` (enabled by
default) and `--with-libnghttp2` (mandatory when DoH is enabled).
When DoH support is disabled the library is not linked-in and support
for http(s) protocol is disabled in the netmgr, named and dig.
The Makefile.tests was modifying global AM_CFLAGS and LDADD and could
accidentally pull /usr/include to be listed before the internal
libraries, which is known to cause problems if the headers from the
previous version of BIND 9 has been installed on the build machine.
The Windows support has been completely removed from the source tree
and BIND 9 now no longer supports native compilation on Windows.
We might consider reviewing mingw-w64 port if contributed by external
party, but no development efforts will be put into making BIND 9 compile
and run on Windows again.
This commit adds a new configuration option to set the receive and send
buffer sizes on the TCP and UDP netmgr sockets. The default is `0`
which doesn't set any value and just uses the value set by the operating
system.
There's no magic value here - set it too small and the performance will
drop, set it too large, the buffers can fill-up with queries that have
already timeouted on the client side and nobody is interested for the
answer and this would just make the server clog up even more by making
it produce useless work.
The `netstat -su` can be used on POSIX systems to monitor the receive
and send buffer errors.
