DNS_R_NCACHENXRRSET can be return when zones are in transition state
from being unsigned to signed and signed to unsigned. The validation
should be resumed and should result in a insecure answer.
While libltdl is a feature-rich library, BIND 9 code only uses its basic
capabilities, which are also provided by libuv and which BIND 9 already
uses for other purposes. As libuv's cross-platform shared library
handling interface is modeled after the POSIX dlopen() interface,
converting code using the latter to the former is simple. Replace
libltdl function calls with their libuv counterparts, refactoring the
code as necessary. Remove all use of libltdl from the BIND 9 source
tree.
The cleanup code that would clean the object after plugin/dlz/dyndb
loading has failed was duplicating the destructor for the object, so
instead of the extra code, we just use the destructor instead.
Make sure an error gets logged when any lt_dlopen() call in the source
tree fails. Also make sure that NULL values returned by lt_dlerror()
are replaced with a generic error message to prevent passing NULL as an
argument for the %s format specifier.
The redundant lt_dlerror() calls were taken from the examples to clean
any previous errors from lt_dl...() calls. However upon code
inspection, it was discovered there are no such paths that could cause
the lt_dlerror() to return spurious error messages.
Stub zones don't make use of AXFR/IXFR for the transfering of zone
data, instead, a single query is issued to the master asking for
their nameserver records (NS).
That works fine unless master is configured with 'minimal-responses'
set to yes, in which case glue records are not provided by master
in the answer with nameservers authoritative for the zone, leaving
stub zones with incomplete databases.
This commit fix this problem in a simple way, when the answer with
the authoritative nameservers is received from master (stub_callback),
for each nameserver listed (save_nsrrset), a A and AAAA records for
the name is verified in the additional section, and if not present
a query is created to resolve the corresponsing missing glue.
A struct 'stub_cb_args' was added to keep relevant information for
performing a query, like TSIG key, udp size, dscp value, etc, this
information is borrowed from, and created within function 'ns_query',
where the resolving of nameserver from master starts.
A new field was added to the struct 'dns_stub', an atomic integer,
namely pending_requests, which is used to keep how many queries are
created when resolving nameserver addresses that were missing in
the glue.
When the value of pending_requests is zero we know we can release
resources, adjust zone timers, dump to zone file, etc.
The DNS Flag Day 2020 aims to remove the IP fragmentation problem from
the UDP DNS communication. In this commit, we implement the required
changes and simplify the logic for picking the EDNS Buffer Size.
1. The defaults for `edns-udp-size`, `max-udp-size` and
`nocookie-udp-size` have been changed to `1232` (the value picked by
DNS Flag Day 2020).
2. The probing heuristics that would try 512->4096->1432->1232 buffer
sizes has been removed and the resolver will always use just the
`edns-udp-size` value.
3. Instead of just disabling the PMTUD mechanism on the UDP sockets, we
now set IP_DONTFRAG (IPV6_DONTFRAG) flag. That means that the UDP
packets won't get ever fragmented. If the ICMP packets are lost the
UDP will just timeout and eventually be retried over TCP.
While working on 'rndc dnssec -rollover' I noticed the following
(small) issues:
- The key files where updated with hints set to "-when" and that
should always be "now.
- The kasp system test did not properly update the test number when
calling 'rndc dnssec -checkds' (and ensuring that works).
- There was a missing ']' in the rndc.c help output.
Add to the keymgr a function that will schedule a rollover. This
basically means setting the time when the key needs to retire,
and updating the key lifetime, then update the state file. The next
time that named runs the keymgr the new lifetime will be taken into
account.
After backporting #1870 to 9.11-S I saw that the condition check there
is different than in the main branch. In 9.11-S "stale" can mean
stale and serve-stale, or not active (awaiting cleanup). In 9.16 and
later versions, "stale" is stale and serve-stale, and "ancient" means
not active (awaiting cleanup). An "ancient" RRset is one that is not
active (TTL expired) and is not eligble for serve-stale.
Update the condition for rndc dumpdb -expired to closer match what is
in 9.11-S.
The kasp code had bad implicit size values for the cryptographic
algorithms Ed25519 and Ed448. When creating keys they would never
match the dnssec-policy, leading to new attempts to create keys.
These algorithms were previously not yet added to the system tests,
due to lack of availability on some systems.
named-checkconf treats the following configuration as valid:
options {
rrset-order {
order none;
};
};
Yet, the above configuration causes named to crash on startup with:
order.c:74: REQUIRE(mode == 0x00000800 || mode == 0x00000400 || mode == 0x00800000) failed, back trace
Add DNS_RDATASETATTR_NONE to the list of RRset ordering modes accepted
by dns_order_add() to allow "order none" to be used in "rrset-order"
rules. This both prevents the aforementioned crashes and addresses the
discrepancy between named-checkconf and named.
The fuzzing harness operates on dns_message_t in non-standard ways
and if 'sig0name' is non-NULL when msgresetsigs() and
dns_message_renderreset() are called it should be cleaned up.
The dns_message_create() function cannot soft fail (as all memory
allocations either succeed or cause abort), so we change the function to
return void and cleanup the calls.
This commit fix the problems that arose when moving the dns_message_t
object from fetchctx_t to the query structure.
Since the lifetime of query objects are different than that of a fetchctx
and the dns_message_t object held by the query may be being used by some
external module, e.g. validator, even after the query may have been destroyed,
propery handling of the references to the message were added in this commit to
avoid accessing an already destroyed object.
Specifically, in rctx_done(), a reference to the message is attached at
the beginning of the function and detached at the end, since a possible call
to fctx_cancelquery() would release the dns_message_t object, and in the next
lines of code a call to rctx_nextserver() or rctx_chaseds() would require
a valid pointer to the same object.
In valcreate() a new reference is attached to the message object, this
ensures that if the corresponding query object is destroyed before the
validator attempts to access it, no invalid pointer access occurs.
In validated() we have to attach a new reference to the message, since
we destroy the validator object at the beginning of the function,
and we need access to the message in the next lines of the same function.
rctx_nextserver() and rctx_chaseds() functions were adapted to receive
a new parameter of dns_message_t* type, this was so they could receive a
valid reference to a dns_message_t since using the response context respctx_t
to access the message through rctx->query->rmessage could lead to an already
released reference due to the query being canceled.
The assertion failure REQUIRE(msg->state == DNS_SECTION_ANY),
caused by calling dns_message_setclass within function resquery_response()
in resolver.c, was happening due to wrong management of dns message_t
objects used to process responses to the queries issued by the resolver.
Before the fix, a resolver's fetch context (fetchctx_t) would hold
a pointer to the message, this same reference would then be used over all
the attempts to resolve the query, trying next server, etc... for this to work
the message object would have it's state reset between each iteration, marking
it as ready for a new processing.
The problem arose in a scenario with many different forwarders configured,
managing the state of the dns_message_t object was lacking better
synchronization, which have led it to a invalid dns_message_t state in
resquery_response().
Instead of adding unnecessarily complex code to synchronize the object,
the dns_message_t object was moved from fetchctx_t structure to the
query structure, where it better belongs to, since each query will produce
a response, this way whenever a new query is created an associated
dns_messate_t is also created.
This commit deals mainly with moving the dns_message_t object from fetchctx_t
to the query structure.
Since Mac OS X 10.1, Mach-O object files are by default built with a
so-called two-level namespace which prevents symbol lookups in BIND unit
tests that attempt to override the implementations of certain library
functions from working as intended. This feature can be disabled by
passing the "-flat_namespace" flag to the linker. Fix unit tests
affected by this issue on macOS by adding "-flat_namespace" to LDFLAGS
used for building all object files on that operating system (it is not
enough to only set that flag for the unit test executables).
By changing the check in 'rdatasetiter_first' and 'rdatasetiter_next'
from "now > header->rdh_ttl" to "now - RBDTB_VIRTUAL > header->rdh_ttl"
we include expired rdataset entries so that they can be used for
"rndc dumpdb -expired".
The message buffer passed to ns__client_request is only valid for
the life of the the ns__client_request call. Save a copy of it
when we recurse or process a update as ns__client_request will
return before those operations complete.
Each dns_rpz_zone_t structure keeps a hash table of the names this RPZ
database contains. Here is what happens when an RPZ is updated:
- a new hash table is prepared for the new version of the RPZ by
iterating over it; each name found is added to the summary RPZ
database,
- every name added to the new hash table is searched for in the old
hash table; if found, it is removed from the old hash table,
- the old hash table is iterated over; all names found in it are
removed from the summary RPZ database (because at that point the old
hash table should only contain names which are not present in the
new version of the RPZ),
- the new hash table replaces the old hash table.
When the new version of the RPZ is iterated over, if a given name is
spelled using a different letter case than in the old version of the
RPZ, the new variant will hash to a different value than the old
variant, which means it will not be removed from the old hash table.
When the old hash table is subsequently iterated over to remove
seemingly deleted names, the old variant of the name will still be
there, causing the name to be deleted from the summary RPZ database
(which effectively causes a given rule to be ignored).
The issue can be triggered not just by altering the case of existing
names in an RPZ, but also by adding sibling names spelled with a
different letter case. This is because RBT code preserves case when
node splitting occurs. The end result is that when the RPZ is iterated
over, a given name may be using a different case than in the zone file
(or XFR contents).
Fix by downcasing all names found in the RPZ database before adding them
to the summary RPZ database.
The clang 12 has a new warning that warns when using multi-line strings
in the string arrays, f.e.:
{ "aa",
"b"
"b",
"cc" }
would generate warning like this:
private_test.c:162:7: error: suspicious concatenation of string literals in an array initialization; did you mean to separate the elements with a comma? [-Werror,-Wstring-concatenation]
"33333/RSASHA1" };
^
private_test.c:161:7: note: place parentheses around the string literal to silence warning
"Done removing signatures for key "
^
private_test.c:197:7: error: suspicious concatenation of string literals in an array initialization; did you mean to separate the elements with a comma? [-Werror,-Wstring-concatenation]
"NSEC chain",
^
private_test.c:196:7: note: place parentheses around the string literal to silence warning
"Removing NSEC3 chain 1 0 30 DEAF / creating "
^
2 errors generated.
Mark Andrews
Ondřej SurýandMichał Kępień
Ondřej SurýandMichał Kępień
Michal Nowak
Diego Fronza
Matthijs Mekking