When 'stale-answer-client-timeout' is 0, named is allowed to return
a stale answer immediately, while also initiating a new query to get
the real answer. This mode is activated in ns__query_start() by setting
the 'qctx->options.stalefirst' optoin to 'true' before calling the
query_lookup() function, but not when the zone is known to be
authoritative to the server. When the zone is authoritative, and
query_looup() finds out that the requested name is a delegation,
then before proceeding with the query, named tries to look it up
in the cache first. Here comes the issue that it doesn't consider
enabling 'qctx->options.stalefirst' in this case, and so the
'stale-answer-client-timeout 0' setting doesn't work for those
delegated zones - instead of immediately returning the stale answer
(if it exists), named tries to resolve it.
Fix this issue by enabling 'qctx->options.stalefirst' in the
query_zone_delegation() function just before named looks up the name
in the cache using a new query_lookup() call. Also, if nothing was
found in the cache, don't initiate another query_lookup() from inside
query_notfound(), and let query_notfound() do its work, i.e. it will
call query_delegation() for further processing.
(cherry picked from commit 412aa881f2)
This will help identify the broken server if we happen to break
EDNS version negotiation. It will also help protect the client
from spoofed BADVERSION responses.
(cherry picked from commit 0d9cab1555)
Pass NULL as edectx for the fetch_and_forget() fetches as nobody
is reading the EDE contexts and it can mess the main client buffer.
(cherry picked from commit fe48290140)
When -T cookiealwaysvalid is passed to named, DNS cookie checks for
the incoming queries always pass, given they are structurally correct.
(cherry picked from commit 807ef8545d)
there was a database bug in which dns_db_find() could get a partial
match for the query name, but still set foundname to match the full
query name. this triggered an assertion when query_addwildcardproof()
assumed that foundname would be shorter.
the database bug has been fixed, but in case it happens again, we
can just copy the name instead of splitting it. we will also log a
warning that the closest-encloser name was invalid.
maxlabels is the suffix length that corresponds to the latest
NXDOMAIN response. minlabels is the suffix length that corresponds
to longest found existing name.
(cherry picked from commit 67f31c5046)
Extended DNS Error message EDE 20 (Not Authoritative) is now sent when
client request recursion (RD) but the server has recursion disabled.
RFC 8914 mention EDE 20 should also be returned if the client doesn't
have the RD bit set (and recursion is needed) but it doesn't apply for
BIND as BIND would try to resolve from the "deepest" referral in
AUTHORITY section. For example, if the client asks for "www.isc.org/A"
but the server only knows the root domain, it will returns NOERROR but
no answer for "www.isc.og/A", just the list of other servers to ask.
(cherry picked from commit 24ffbdcfea)
Answers to an "ANY" query which are processed by the RPZ "passthru"
policy have the response-policy's 'max-policy-ttl' value unexpectedly
applied. Do not change the records' TTL when RPZ uses a policy which
does not alter the answer.
(cherry picked from commit 5633dc90d3)
if the NS_QUERY_DONE_BEGIN or NS_QUERY_DONE_SEND hook is
used in a plugin and returns NS_HOOK_RETURN, some of the
cleanup in ns_query_done() can be skipped over, leading
to reference leaks that can cause named to hang on shut
down.
this has been addressed by adding more housekeeping
code after the cleanup: tag in ns_query_done().
(cherry picked from commit c2e4358267)
After a reconfiguration the old view can be left without a valid
'rpzs' member, because when the RPZ is not changed during the named
reconfiguration 'rpzs' "migrate" from the old view into the new
view, so when a query resumes it can find that 'qctx->view->rpzs'
is NULL which query_resume() currently doesn't expect to happen if
it's recursing and 'qctx->rpz_st' is not NULL.
Fix the issue by adding a NULL-check. In order to not split the log
message to two different log messages depending on whether
'qctx->view->rpzs' is NULL or not, change the message to not log
the RPZ policy's "version" which is just a runtime counter and is
most likely not very useful for the users.
(cherry picked from commit 3ea2fbc238)
Instead of mixing the dns_resolver and dns_validator units directly with
the EDE code, split-out the dns_ede functionality into own separate
compilation unit and hide the implementation details behind abstraction.
Additionally, the EDE codes are directly copied into the ns_client
buffers by passing the EDE context to dns_resolver_createfetch().
This makes the dns_ede implementation simpler to use, although sligtly
more complicated on the inside.
Co-authored-by: Colin Vidal <colin@isc.org>
Co-authored-by: Ondřej Surý <ondrej@isc.org>
(cherry picked from commit 2f8e0edf3b)
Add support for EDE codes 1 (Unsupported DNSKEY Algorithm) and 2
(Unsupported DS Digest Type) which might occurs during DNSSEC
validation in case of unsupported DNSKEY algorithm or DS digest type.
Because DNSSEC internally kicks off various fetches, we need to copy
all encountered extended errors from fetch responses to the fetch
context. Upon an event, the errors from the fetch context are copied
to the client response.
(cherry picked from commit 46a58acdf5)
Extended DNS error mechanism (EDE) enables to have several EDE raised
during a DNS resolution (typically, a DNSSEC query will do multiple
fetches which each of them can have an error). Add support to up to 3
EDE errors in an DNS response. If duplicates occur (two EDEs with the
same code, the extra text is not compared), only the first one will be
part of the DNS answer.
Because the maximum number of EDE is statically fixed, `ns_client_t`
object own a static vector of `DNS_DE_MAX_ERRORS` (instead of a linked
list, for instance). The array can be fully filled (all slots point to
an allocated `dns_ednsopt_t` object) or partially filled (or
empty). In such case, the first NULL slot means there is no more EDE
objects.
(cherry picked from commit 4096f27130)
When answering queries, don't add data to the additional section if
the answer has more than 13 names in the RDATA. This limits the
number of lookups into the database(s) during a single client query,
reducing query processing load.
Also, don't append any additional data to type=ANY queries. The
answer to ANY is already big enough.
(cherry picked from commit a1982cf1bb)
In dns_zone_getdnssecsignstats, dns_zone_getrcvquerystats and
dns_zone_getrequeststats attach to the statistics structure.
(cherry picked from commit fb50a71159)
Add support for Extended DNS Errors (EDE) error 22: No reachable
authority. This occurs when after a timeout delay when the resolver is
trying to query an authority server.
(cherry picked from commit d13e94b930)
Commit amended in order to fix usage of isc_log_write (adding dns_lctx
parameter)
Previously, the update policy rules check was moved earlier in the
sequence, and the keep rule match pointers were kept to maintain the
ability to verify maximum records by type.
However, these pointers can become invalid if server reloading
or reconfiguration occurs before update completion. To prevent
this issue, extract the maximum records by type value immediately
during processing and only keep the copy of the values instead of the
full ssurule.
(cherry picked from commit 44a54a29d8)
Instead of cleaning the dns_badcache opportunistically, add per-loop
LRU, so each thread-loop can clean the expired entries. This also
allows removal of the atomic operations as the badcache entries are now
immutable, instead of updating the badcache entry in place, the old
entry is now deleted from the hashtable and the LRU list, and the new
entry is inserted in the LRU.
(cherry picked from commit 2cb5a6210f)
Re-split format strings that had been poorly split by multiple
clang-format runs using different versions of clang-format.
(cherry picked from commit a24d6e1654)
maxlabels is the suffix length that corresponds to the latest
NXDOMAIN response. minlabels is the suffix length that corresponds
to longest found existing name.
(cherry picked from commit 67f31c5046)
Rename check_recursionquota() to acquire_recursionquota(), and
implement a new function called release_recursionquota() to
reverse the action. It helps with decreasing code duplication.
(cherry picked from commit 7bd44a4182)
In two places, after linking the client to the manager's
"recursing-clients" list using the check_recursionquota()
function, the query.c module fails to unlink it on error
paths. Fix the bugs by unlinking the client from the list.
Also make sure that unlinking happens before detaching the
client's handle, as it is the logically correct order, e.g.
in case if it's the last handle and ns__client_reset_cb()
can be called because of the detachment.
(cherry picked from commit 36c4808903)
The 'nodetach' member is a leftover from the times when non-zero
'stale-answer-client-timeout' values were supported, and currently
is always 'false'. Clean up the member and its usage.
(cherry picked from commit b8c068835e)
Query and response log shares the same flags. Move flags logging out of
log_query to share it with log_response. Use buffer instead of snprintf
to fill flags a bit faster.
Signed-off-by: Petr Menšík <pemensik@redhat.com>
(cherry picked from commit e6b19af2dd)
Remove answer flag from log, log instead count of records for each
message section. Include EDNS version and few flags of response. Add
also status of result.
Still does not include body of responses rrset.
(cherry picked from commit 6f879aba65)
Log to the querylog the rcode of a previous query using
the identifier 'response:' to diffenciate queries from
responses.
(cherry picked from commit 5fad79c92f)
Return partial match from dns_db_find/dns_db_find when requested
to short circuit the closest encloser discover process. Most of the
time this will be the actual closest encloser but may not be when
there yet to be committed / cleaned up versions of the zone with
names below the actual closest encloser.
(cherry picked from commit d42ea08f16)
Log canceled queries (e.g. when shutting down a hung fetch)
in DEBUG3 level instead of DEBUG1 which is used for the
"unrecognized" result codes.
(cherry picked from commit 8bb9568467)
MAX_RESTARTS is no longer hard-coded; ns_server_setmaxrestarts()
and dns_client_setmaxrestarts() can now be used to modify the
max-restarts value at runtime. in both cases, the default is 11.
(cherry picked from commit c5588babaf)
the number of steps that can be followed in a CNAME chain
before terminating the lookup has been reduced from 16 to 11.
(this is a hard-coded value, but will be made configurable later.)
(cherry picked from commit 05d78671bb)
When automatic-interface-scan is disabled, the route socket was still
being opened. Add new API to connect / disconnect from the route socket
only as needed.
Additionally, move the block that disables periodic interface rescans to
a place where it actually have access to the configuration values.
Previously, the values were being checked before the configuration was
loaded.
(cherry picked from commit b26079fdaf)
Due to the maximum query restart limitation a long CNAME chain
it is cut after 16 queries but named still returns NOERROR.
Return SERVFAIL instead and the partial answer.
(cherry picked from commit b621f1d88e)
When sending fails, the ns__client_request() would not reset the
connection and continue as nothing is happening. This comes from the
model that we don't care about failed UDP sends because datagrams are
unreliable anyway, but it greatly affects TCP connections with
keep-alive.
The worst case scenario is as follows:
1. the 3-way TCP handshake gets completed
2. the libuv calls the "uv_connection_cb" callback
3. the TCP connection gets queue because of the tcp-clients quota
4. the TCP client sends as many DNS messages as the buffers allow
5. the TCP connection gets dropped by the client due to the timeout
6. the TCP connection gets accepted by the server
7. the data already sent by the client gets read
8. all sending fails immediately because the TCP connection is dead
9. we consume all the data in the buffer in a very tight loop
As it doesn't make sense to trying to process more data on the TCP
connection when the sending is failing, drop the connection immediately
on the first sending error.
As ns_query_init() cannot fail now, remove the error paths, especially
in ns__client_setup() where we now don't have to care what to do with
the connection if setting up the client could fail. It couldn't fail
even before, but now it's formal.
Clear qctx->zversion when clearing qctx->zrdataset et al in
lib/ns/query.c:qctx_freedata. The uncleared pointer could lead to
an assertion failure if zone data needed to be re-saved which could
happen with stale data support enabled.
View matching on an incoming query checks the query's signature,
which can be a CPU-heavy task for a SIG(0)-signed message. Implement
an asynchronous mode of the view matching function which uses the
offloaded signature checking facilities, and use it for the incoming
queries.
