Artem Boldariev [Mon, 21 Feb 2022 14:02:32 +0000 (16:02 +0200)]
Mention TLS certs verification in the CHANGES and Release Notes
This commit adds points to the CHANGES and the release notes about
supporting remote TLS certificates verification and support for Strict
and Mutual TLS transport connections verification.
Artem Boldariev [Mon, 21 Feb 2022 08:25:41 +0000 (10:25 +0200)]
Update the "Known Issues"
Mention that some old cryptographic library versions lack the
functionality to implement ignoring the Subject field (and thus the
Common Name) when establishing DoT connections.
Artem Boldariev [Tue, 8 Feb 2022 17:02:05 +0000 (19:02 +0200)]
Extend the 'doth' system test with Strict/Mutual TLS checks
This commit extends the 'doth' system test with a set of Strict/Mutual
TLS related checks.
This commit also makes each doth NS instance use its own TLS
certificate that includes FQDN, IPv4, and IPv6 addresses, issued using
a common Certificate Authority, instead of ad-hoc certs.
Extend servers initialisation timeout to 60 seconds to improve the
tests stability in the CI as certain configurations could fail to
initialise on time under load.
Artem Boldariev [Tue, 1 Feb 2022 14:57:27 +0000 (16:57 +0200)]
Document supported TLS authentication modes
This commit updates the reference manual with short descriptions of
different TLS authentication modes, as mentioned in the RFC 9103,
Section 9.3 (Opportunistic TLS, Strict TLS, Mutual TLS), and mentions
how these authentication modes can be achieved via BIND's
configuration file.
Artem Boldariev [Wed, 26 Jan 2022 13:26:08 +0000 (15:26 +0200)]
Add support for Strict/Mutual TLS into BIND
This commit adds support for Strict/Mutual TLS into BIND. It does so
by implementing the backing code for 'hostname' and 'ca-file' options
of the 'tls' statement. The commit also updates the documentation
accordingly.
Artem Boldariev [Wed, 19 Jan 2022 11:10:08 +0000 (13:10 +0200)]
Add support for Strict/Mutual TLS to dig
This commit adds support for Strict/Mutual TLS to dig.
The new command-line options and their behaviour are modelled after
kdig (+tls-ca, +tls-hostname, +tls-certfile, +tls-keyfile) for
compatibility reasons. That is, using +tls-* is sufficient to enable
DoT in dig, implying +tls-ca
If there is no other DNS transport specified via command-line,
specifying any of +tls-* options makes dig use DoT. In this case, its
behaviour is the same as if +tls-ca is specified: that is, the remote
peer's certificate is verified using the platform-specific
intermediate CA certificates store. This behaviour is introduced for
compatibility with kdig.
Artem Boldariev [Thu, 13 Jan 2022 12:35:24 +0000 (14:35 +0200)]
Add ISC_R_TLSBADPEERCERT error code to the TLS related code
This commit adds support for ISC_R_TLSBADPEERCERT error code, which is
supposed to be used to signal for TLS peer certificates verification
in dig and other code.
The support for this error code is added to our TLS and TLS DNS
implementations.
This commit also adds isc_nm_verify_tls_peer_result_string() function
which is supposed to be used to get a textual description of the
reason for getting a ISC_R_TLSBADPEERCERT error.
Artem Boldariev [Tue, 18 Jan 2022 16:31:11 +0000 (18:31 +0200)]
Extend TLS context cache with CA certificates store
This commit adds support for keeping CA certificates stores associated
with TLS contexts. The intention is to keep one reusable store per a
set of related TLS contexts.
Artem Boldariev [Thu, 30 Dec 2021 21:24:25 +0000 (23:24 +0200)]
Add utility functions to manipulate X509 certificate stores
This commit adds a set of high-level utility functions to manipulate
the certificate stores. The stores are needed to implement TLS
certificates verification efficiently.
Aram Sargsyan [Thu, 17 Mar 2022 14:09:21 +0000 (14:09 +0000)]
Put some missing dns_rdata_freestruct() calls in catz.c
A successful call to `dns_rdata_tostruct()` expects an accompanying
call to `dns_rdata_freestruct()` to free up any memory that could have
been allocated during the first call.
In catz.c there are several places where `dns_rdata_freestruct()` call
is skipped.
Aram Sargsyan [Tue, 8 Feb 2022 11:47:48 +0000 (11:47 +0000)]
Log a warning when catz is told to modify a zone not added by catz
Catz logs a warning message when it is told to modify a zone which was
not added by the current catalog zone.
When logging a warning, distinguish the two cases when the zone
was not added by a catalog zone at all, and when the zone was
added by a different catalog zone.
Tony Finch [Mon, 29 Apr 2019 12:56:05 +0000 (13:56 +0100)]
Teach dnssec-settime to read times that it writes
The dnssec-settime -p and -up options print times in asctime() and
UNIX time_t formats, respectively. The asctime() format can also be
found inside K*.key public key files. Key files also contain times in
the YYYYMMDDHHMMSS format that can be used in timing parameter
options.
The dnssec-settime -p and -up time formats are now acceptable in
timing parameter options to dnssec-settime and dnssec-keygen, so it is
no longer necessary to parse key files to retrieve times that are
acceptable in timing parameter options.
Ondřej Surý [Wed, 23 Mar 2022 15:16:53 +0000 (16:16 +0100)]
Remove ns_client_t .shuttingdown member
The way the ns_client_t .shuttingdown member was practically dead code.
The .shuttingdown would be set to true only in ns__client_put() function
meaning that we have detached from all ns_client_t .*handles and the
ns_client_t object being freed:
Even if the isc_nmhandle_detach(...) was the last handle detach, it
would mean that immediatelly, after calling the isc_nmhandle_detach(),
we would be causing use-after-free, because the ns_client_t is
immediatelly destroyed after setting .shuttingdown to true.
The similar code in the query_hookresume() already noticed this:
/*
* This event is running under a client task, so it's safe to detach
* the fetch handle. And it should be done before resuming query
* processing below, since that may trigger another recursion or
* asynchronous hook event.
*/
Ondřej Surý [Wed, 23 Mar 2022 12:57:15 +0000 (13:57 +0100)]
Remove extrahandle size from netmgr
Previously, it was possible to assign a bit of memory space in the
nmhandle to store the client data. This was complicated and prevents
further refactoring of isc_nmhandle_t caching (future work).
Instead of caching the data in the nmhandle, allocate the hot-path
ns_client_t objects from per-thread clientmgr memory context and just
assign it to the isc_nmhandle_t via isc_nmhandle_set().
Ondřej Surý [Wed, 23 Mar 2022 12:57:15 +0000 (13:57 +0100)]
Remove extra copies and stray members from ns_client_t
The ns_client_t is always attached to ns_clientmgr_t which has
associated memory context, server context, task and threadid. Use those
directly from the ns_clientmgr_t instead of attaching it to an extra
copy in ns_client_t to make the ns_client_t more sleek and lean.
Additionally, remove some stray ns_client_t struct members that were not
used anywhere.
Ondřej Surý [Sat, 5 Mar 2022 12:46:52 +0000 (13:46 +0100)]
Remove workaround for ancient clang versions (<< 3.2 and << 4.0.1)
Some ancient versions of clang reported uninitialized memory use false
positive (see https://bugs.llvm.org/show_bug.cgi?id=14461). Since clang
4.0.1 has been long obsoleted, just remove the workarounds.
Ondřej Surý [Mon, 11 Oct 2021 11:43:12 +0000 (13:43 +0200)]
Remove use of the inline keyword used as suggestion to compiler
Historically, the inline keyword was a strong suggestion to the compiler
that it should inline the function marked inline. As compilers became
better at optimising, this functionality has receded, and using inline
as a suggestion to inline a function is obsolete. The compiler will
happily ignore it and inline something else entirely if it finds that's
a better optimisation.
Therefore, remove all the occurences of the inline keyword with static
functions inside single compilation unit and leave the decision whether
to inline a function or not entirely on the compiler
NOTE: We keep the usage the inline keyword when the purpose is to change
the linkage behaviour.
Ondřej Surý [Fri, 18 Mar 2022 08:50:58 +0000 (09:50 +0100)]
Make netmgr the authority on number of threads running
Instead of passing the "workers" variable back and forth along with
passing the single isc_nm_t instance, add isc_nm_getnworkers() function
that returns the number of netmgr threads are running.
Change the ns_interfacemgr and ns_taskmgr to utilize the newly acquired
knowledge.
Tony Finch [Fri, 18 Mar 2022 14:50:36 +0000 (14:50 +0000)]
Avoid using C99 variable length arrays
From an attacker's point of view, a VLA declaration is essentially a
primitive for performing arbitrary arithmetic on the stack pointer. If
the attacker can control the size of a VLA they have a very powerful
tool for causing memory corruption.
To mitigate this kind of attack, and the more general class of stack
clash vulnerabilities, C compilers insert extra code when allocating a
VLA to probe the growing stack one page at a time. If these probes hit
the stack guard page, the program will crash.
From the point of view of a C programmer, there are a few things to
consider about VLAs:
* If it is important to handle allocation failures in a controlled
manner, don't use VLAs. You can use VLAs if it is OK for
unreasonable inputs to cause an uncontrolled crash.
* If the VLA is known to be smaller than some known fixed size,
use a fixed size array and a run-time check to ensure it is large
enough. This will be more efficient than the compiler's stack
probes that need to cope with arbitrary-size VLAs.
* If the VLA might be large, allocate it on the heap. The heap
allocator can allocate multiple pages in one shot, whereas the
stack clash probes work one page at a time.
Most of the existing uses of VLAs in BIND are in test code where they
are benign, but there was one instance in `named`, in the GSS-TSIG
verification code, which has now been removed.
This commit adjusts the style guide and the C compiler flags to allow
VLAs in test code but not elsewhere.
Tony Finch [Thu, 10 Mar 2022 13:04:08 +0000 (13:04 +0000)]
Remove a redundant variable-length array
In the GSS-TSIG verification code there was an alarming
variable-length array whose size came off the network, from the
signature in the request. It turned out to be safe, because the caller
had previously checked that the signature had a reasonable size.
However, the safety checks are in the generic TSIG implementation, and
the risky VLA usage was in the GSS-specific code, and they are
separated by the DST indirection layer, so it wasn't immediately
obvious that the risky VLA was in fact safe.
In fact this risky VLA was completely unnecessary, because the GSS
signature can be verified in place without being copied to the stack,
like the message covered by the signature. The `REGION_TO_GBUFFER()`
macro backwardly assigns the region in its left argument to the GSS
buffer in its right argument; this is just a pointer and length
conversion, without copying any data. The `gss_verify_mic()` call uses
both message and signature GSS buffers in a read-only manner.
Aram Sargsyan [Sun, 13 Mar 2022 13:47:44 +0000 (13:47 +0000)]
Add various dig/host tests for TCP/UDP socket error handling cases
Rework the "ans8" server in the "digdelv" system test to support various
modes of operations using a control channel.
The supported modes are:
1. `silent` (do not respond)
2. `close` (UDP: same as `silent`; TCP: also close the connection)
3. `servfail` (always respond with `SERVFAIL`)
4. `unstable` (constantly switch between `silent` and `servfail`)
Add multiple tests to check the handling of both TCP and UDP socket
error scenarios in dig/host.
Aram Sargsyan [Sun, 13 Mar 2022 13:47:16 +0000 (13:47 +0000)]
Fix dig error when trying the next server after a TCP connection failure
When encountering a TCP connection error while trying to initiate a
connection to a server, dig erroneously cancels the lookup even when
there are other server(s) to try, which results in an assertion failure.
Cancel the lookup only when there are no more queries left in the
lookup's queries list (i.e. `next` is NULL).
Aram Sargsyan [Fri, 11 Mar 2022 19:37:27 +0000 (19:37 +0000)]
After dig request errors, try to use other servers when they exist
When timing-out or having other types of socket errors during a query,
dig isn't trying to perform the lookup using other servers which exist
in the lookup's queries list.
After configured amount of timeout retries, or after a socket error,
check if there are other queries/servers in the lookup's queries list,
and start the next one if it exists, instead of unconditionally failing.
Aram Sargsyan [Thu, 10 Mar 2022 00:12:37 +0000 (00:12 +0000)]
Add digdelv system test to check timed-out result followed by a SERVFAIL
This test ensures that `dig` retries with another attempt after a
timed-out request, and that it does not crash when the retried
request returns a SERVFAIL result. See [GL #3020] for the latter
issue.
Aram Sargsyan [Wed, 9 Mar 2022 19:45:54 +0000 (19:45 +0000)]
When resending a UDP request, insert the query to the lookup's list
When a query times out, and `dig` (or `host`) creates a new query
to resend the request, it is being prepended to the lookup's queries
list, which can cause a confusion later, making `dig` (or `host`)
believe that there is another new query in the list, but that is
actually the old one, which was timed out. That mistake will result
in an assertion failure.
That can happen, in particular, when after a timed out request,
the retried request returns a SERVFAIL result, and the recursion
is enabled, and `+nofail` option was used with `dig` (that is the
default behavior in `host`, unless the `-s` option is provided).
Fix the problem by inserting the query just after the current,
timed-out query, instead of prepending to the list.
Before calling start_udp() detach `l->current_query`, like it is
done in another place in the function.
Slightly update a couple of debug messages to make them more
consistent.
Aram Sargsyan [Thu, 10 Mar 2022 17:30:34 +0000 (17:30 +0000)]
Fix an issue in dig when retrying with the next server after SERVFAIL
After a query results in a SERVFAIL result, and there is another
registered query in the lookup's queries list, `dig` starts the next
query to try another server, but for some reason, reports about that
also when the current query is in the head of the list, even if there
is no other query in the list to try.
Use the same condition for both decisions, and after starting the next
query, jump to the "detach_query" label instead of "next_lookup",
because there is no need to start the next lookup after we just started
a query in the current lookup.
Ondřej Surý [Thu, 17 Mar 2022 20:28:29 +0000 (21:28 +0100)]
Change xfer-out timer message log level to DEBUG(1)
When max-transfer-*-out timeouts were reintroduced, the log message
about starting the timer was errorneously left as ISC_LOG_ERROR.
Change the log level of said message to ISC_LOG_DEBUG(1).
Ondřej Surý [Sun, 13 Mar 2022 12:05:27 +0000 (13:05 +0100)]
Add couple missing braces around single-line statements
The clang-format-15 has new option InsertBraces that could add missing
branches around single line statements. Use that to our advantage
without switching to not-yet-released LLVM version to add missing braces
in couple of places.
Ondřej Surý [Wed, 16 Mar 2022 10:11:38 +0000 (11:11 +0100)]
Update the isc_ht unit test to also tesh rehashing
As incremental rehashing has been added to isc_ht implementation, we
need to test whether the rehashing works.
Update the isc_ht unit test to test:
* preinitialized hash table large enough to hold all the elements
* smallest hash table that fully grows to hold all the elements
* partially preinitialized hash table that grows
* iterating while rehashing is in progress
Ondřej Surý [Tue, 15 Mar 2022 20:45:33 +0000 (21:45 +0100)]
Implement incremental hash table resizing in isc_ht
Previously, an incremental hash table resizing was implemented for the
dns_rbt_t hash table implementation. Using that as a base, also
implement the incremental hash table resizing also for isc_ht API
hashtables:
1. During the resize, allocate the new hash table, but keep the old
table unchanged.
2. In each lookup, delete, or iterator operation, check both tables.
3. Perform insertion operations only in the new table.
4. At each insertion also move <r> elements from the old table to
the new table.
5. When all elements are removed from the old table, deallocate it.
To ensure that the old table is completely copied over before the new
table itself needs to be enlarged, it is necessary to increase the
size of the table by a factor of at least (<r> + 1)/<r> during resizing.
In our implementation <r> is equal to 1.
The downside of this approach is that the old table and the new table
could stay in memory for longer when there are no new insertions into
the hash table for prolonged periods of time as the incremental
rehashing happens only during the insertions.
Aram Sargsyan [Thu, 10 Feb 2022 20:06:30 +0000 (20:06 +0000)]
Check if the fetch is shutting down in resume_dslookup()
The fetch can be in the shutting down state when resume_dslookup() is
trying to operate on it.
This is also a security issue, because a malicious actor can set up a
name server which delays certain queries in such a way that the fetch
will time out and shut down, which will cause named to crash.
Add a check to see if the fetch has the shutting down attribute set,
and cancel any further operations on it in such case.
A similar bug had been fixed earlier for the resume_qmin() function,
see [GL #966].
Mark Andrews [Thu, 17 Feb 2022 06:11:26 +0000 (17:11 +1100)]
Skip calling find_coveringnsec if we found a DNAME
This is an optimisation as we can skip a lot of pointless work when we
know there is a DNAME there.
When we have a partial match and a DNAME above the QNAME, the closest
encloser has the same owner as the DNAME, will have the DNAME bit set
in the type map, and we wouldn't use it as we would return the
DNAME + RRSIG(DNAME) instead.
So there is no point in looking for it nor in attempting to check that
it is valid for the QNAME.
Ondřej Surý [Tue, 8 Feb 2022 11:42:34 +0000 (12:42 +0100)]
Run .closehandle_cb asynchrounosly in nmhandle_detach_cb()
When sock->closehandle_cb is set, we need to run nmhandle_detach_cb()
asynchronously to ensure correct order of multiple packets processing in
the isc__nm_process_sock_buffer(). When not run asynchronously, it
would cause:
a) out-of-order processing of the return codes from processbuffer();
b) stack growth because the next TCP DNS message read callback will
be called from within the current TCP DNS message read callback.
The sock->closehandle_cb is set to isc__nm_resume_processing() for TCP
sockets which calls isc__nm_process_sock_buffer(). If the read callback
(called from isc__nm_process_sock_buffer()->processbuffer()) doesn't
attach to the nmhandle (f.e. because it wants to drop the processing or
we send the response directly via uv_try_write()), the
isc__nm_resume_processing() (via .closehandle_cb) would call
isc__nm_process_sock_buffer() recursively.
The below shortened code path shows how the stack can grow:
Instead, if 'sock->closehandle_cb' is set, we need to run detach the
handle asynchroniously in 'isc__nmhandle_detach', so that on line 8 in
the code flow above does not start this recursion. This ensures the
correct order when processing multiple packets in the function
'isc__nm_process_sock_buffer()' and prevents the stack growth.
When not run asynchronously, the out-of-order processing leaves the
first TCP socket open until all requests on the stream have been
processed.
If the pipelining is disabled on the TCP via `keep-response-order`
configuration option, named would keep the first socket in lingering
CLOSE_WAIT state when the client sends an incomplete packet and then
closes the connection from the client side.
Mark Andrews [Wed, 16 Feb 2022 08:20:25 +0000 (19:20 +1100)]
Only update foundname if returning DNS_R_COVERINGNSEC
'setup_delegation' depends on 'foundname' being the value returned
by 'dns_rbt_findnode' in the cache and 'find_coveringnsec' was
modifying 'foundname' when a covering NSEC was not found.
Mark Andrews [Wed, 2 Feb 2022 04:13:39 +0000 (15:13 +1100)]
Look for zones deeper than the current domain or forward name
When caching glue, we need to ensure that there is no closer
source of truth for the name. If the owner name for the glue
record would be answered by a locally configured zone, do not
cache.
Mark Andrews [Fri, 21 Jan 2022 04:36:48 +0000 (15:36 +1100)]
Check cached names for possible "forward only" clause
When caching additional and glue data *not* from a forwarder, we must
check that there is no "forward only" clause covering the owner name
that would take precedence. Such names would normally be allowed by
baliwick rules, but a "forward only" zone introduces a new baliwick
scope.
Mark Andrews [Thu, 20 Jan 2022 23:52:02 +0000 (10:52 +1100)]
Check that the forward declaration is unchanged and not overridden
If we are using a fowarder, in addition to checking that names to
be cached are subdomains of the forwarded namespace, we must also
check that there are no subsidiary forwarded namespaces which would
take precedence. To be safe, we don't cache any responses if the
forwarding configuration has changed since the query was sent.
Ondřej Surý [Sun, 13 Mar 2022 11:13:11 +0000 (12:13 +0100)]
Implement isc_interval_t on top of isc_time_t
Change the isc_interval_t implementation from separate data type and
separate implementation to be shim implementation on top of isc_time_t.
The distinction between isc_interval_t and isc_time_t has been kept
because they are semantically different - isc_interval_t is relative and
isc_time_t is absolute, but this allows isc_time_t and isc_interval_t to
be freely interchangeable, f.e. this:
Ondřej Surý [Fri, 11 Mar 2022 21:34:45 +0000 (22:34 +0100)]
Change isc_timer_reset() usage to never use expires argument
There were two places where expires argument (absolute isc_time_t value)
was being used. Both places has been converted to use relative interval
argument in preparation of simplification and refactoring of isc_timer
API.
Ondřej Surý [Fri, 11 Mar 2022 11:09:35 +0000 (12:09 +0100)]
Refactor isc_timer_create() to just create timer
The isc_timer_create() function was a bit conflated. It could have been
used to create a timer and start it at the same time. As there was a
single place where this was done before (see the previous commit for
nta.c), this was cleaned up and the isc_timer_create() function was
changed to only create new timer.
Ondřej Surý [Fri, 11 Mar 2022 10:50:25 +0000 (11:50 +0100)]
Change lib/dns/nta.c to create inactive timer and then reset it
In nta.c, it was the only place where the active timer was created
directly instead of first creating inactive timer and then starting it
with isc_timer_reset().
Change the code to create inactive timer first, so we can refactor the
isc_timer_create() function.