'dnssec-policy' can now also be set on the options and view level and
a zone that does not set 'dnssec-policy' explicitly will inherit it
from the view or options level.
This requires a new keyword to be introduced: 'none'. If set to
'none' the zone will not be DNSSEC maintained, in other words it will
stay unsigned. You can use this to break the inheritance. Of course
you can also break the inheritance by referring to a different
policy.
The keywords 'default' and 'none' are not allowed when configuring
your own dnssec-policy statement.
Add appropriate tests for checking the configuration (checkconf)
and add tests to the kasp system test to verify the inheritance
works.
Edit the kasp system test such that it can deal with unsigned zones
and views (so setting a TSIG on the query).
The kasp system tests are updated with 'check_cds' calls that will
verify that the correct CDS and CDNSKEY records are published during
a rollover and that they are signed with the correct KSK.
This requires a change in 'dnssec.c' to check the kasp key states
whether the CDS/CDNSKEY of a key should be published or not. If no
kasp state exist, fall back to key timings.
The 'sign_apex()' function has special processing for signing the
DNSKEY RRset such that it will always be signed with the active
KSK. Since CDS and CDNSKEY are also signed with the KSK, it
should have the same special processing. The special processing is
moved into a new function 'tickle_apex_rrset()' and is applied to
all three RR types (DNSKEY, CDS, CDNSKEY).
In addition, when kasp is involved, update the DNSKEY TTL accordingly
to what is in the policy.
Update dns_dnssec_keyactive to differentiate between the roles ZSK
and KSK. A key is active if it is signing but that differs per role.
A ZSK is signing if its ZRRSIG state is in RUMOURED or OMNIPRESENT,
a KSK is signing if its KRRSIG state is in RUMOURED or OMNIPRESENT.
This means that a key can be actively signing for one role but not
the other. Add checks in inline signing (zone.c and update.c) to
cover the case where a CSK is active in its KSK role but not the ZSK
role.
Update the signing code in lib/dns/zone.c and lib/dns/update.c to
use kasp logic if a dnssec-policy is enabled.
This means zones with dnssec-policy should no longer follow
'update-check-ksk' and 'dnssec-dnskey-kskonly' logic, instead the
KASP keys configured dictate which RRset gets signed with what key.
Also use the next rekey event from the key manager rather than
setting it to one hour.
Mark the zone dynamic, as otherwise a zone with dnssec-policy is
not eligble for automatic DNSSEC maintenance.
Update dns_dnssec_get_hints and dns_dnssec_keyactive to use dst_key
functions and thus if dnssec-policy/KASP is used the key states are
being considered.
Add a new variable to 'struct dns_dnsseckey' to signal whether this
key is a zone-signing key (it is no longer true that ksk == !zsk).
Also introduce a hint for revoke.
Update 'dns_dnssec_findzonekeys' and 'dns_dnssec_findmatchingkeys'
to also read the key state file, if available.
Remove 'allzsk' from 'dns_dnssec_updatekeys' as this was only a
hint for logging.
Also make get_hints() (now dns_dnssec_get_hints()) public so that
we can use it in the key manager.
Add a key manager to named. If a 'dnssec-policy' is set, 'named'
will run a key manager on the matching keys. This will do a couple
of things:
1. Create keys when needed (in case of rollover for example)
according to the set policy.
2. Retire keys that are in excess of the policy.
3. Maintain key states according to "Flexible and Robust Key
Rollover" [1]. After key manager ran, key files will be saved to
disk.
[1] https://matthijsmekking.nl/static/pdf/satin2012-Schaeffer.pdf
KEY GENERATION
Create keys according to DNSSEC policy. Zones configured with
'dnssec-policy' will allow 'named' to create DNSSEC keys (similar
to dnssec-keymgr) if not available.
KEY ROLLOVER
Rather than determining the desired state from timing metadata,
add a key state goal. Any keys that are created or picked from the
key ring and selected to be a successor has its key state goal set
to OMNIPRESENT (this key wants to be signing!). At the same time,
a key that is being retired has its key state goal set to HIDDEN.
The keymgr state machine with the three rules will make sure no
introduction or withdrawal of DNSSEC records happens too soon.
KEY TIMINGS
All timings are based on RFC 7583.
The keymgr will return when the next action is happening so
that the zone can set the proper rekey event. Prior to this change
the rekey event will run every hour by default (configurable),
but with kasp we can determine exactly when we need to run again.
The prepublication time is derived from policy.
Add a couple of dst_key functions for determining hints that
consider key states if they are available.
- dst_key_is_unused:
A key has no timing metadata set other than Created.
- dst_key_is_published:
A key has publish timing metadata <= now, DNSKEY state in
RUMOURED or OMNIPRESENT.
- dst_key_is_active:
A key has active timing metadata <= now, RRSIG state in
RUMOURED or OMNIPRESENT.
- dst_key_is_signing:
KSK is_signing and is_active means different things than
for a ZSK. A ZSK is active means it is also signing, but
a KSK always signs its DNSKEY RRset but is considered
active if its DS is present (rumoured or omnipresent).
- dst_key_is_revoked:
A key has revoke timing metadata <= now.
- dst_key_is_removed:
A key has delete timing metadata <= now, DNSKEY state in
UNRETENTIVE or HIDDEN.
When doing rollover in a timely manner we need to have access to the
relevant kasp configured durations.
Most of these are simple get functions, but 'dns_kasp_signdelay'
will calculate the maximum time that is needed with this policy to
resign the complete zone (taking into account the refresh interval
and signature validity).
Introduce parent-propagation-delay, parent-registration-delay,
parent-ds-ttl, zone-max-ttl, zone-propagation-delay.
When signing a zone with dnssec-policy, we don't mind DNSSEC records.
This is useful for testing purposes, and perhaps it is better to
signal this behavior with a different configuration option.
Introduce a new option '-s' for dnssec-settime that when manipulating
timing metadata, it also updates the key state file.
For testing purposes, add options to dnssec-settime to set key
states and when they last changed.
The dst code adds ways to write and read the new key states and
timing metadata. It updates the parsing code for private key files
to not parse the newly introduced metadata (these are for state
files only).
Introduce key goal (the state the key wants to be in).
When reading a key from file, you can set the DST_TYPE_STATE option
to also read the key state.
This expects the Algorithm and Length fields go above the metadata,
so update the write functionality to do so accordingly.
Introduce new DST metadata types for KSK, ZSK, Lifetime and the
timing metadata used in state files.
Write functions to access various elements of the kasp structure,
and the kasp keys. This in preparation of code in dnssec-keygen,
dnssec-settime, named...
Add a number of metadata variables (lifetime, ksk and zsk role).
For the roles we add a new type of metadata (booleans).
Add a function to write the state of the key to a separate file.
Only write out known metadata to private file. With the
introduction of the numeric metadata "Lifetime", adjust the write
private key file functionality to only write out metadata it knows
about.
This stores the dnssec-policy configuration and adds methods to
create, destroy, and attach/detach, as well as find a policy with
the same name in a list.
Also, add structures and functions for creating and destroying
kasp keys.
This commit introduces the initial `dnssec-policy` configuration
statement. It has an initial set of options to deal with signature
and key maintenance.
Add some checks to ensure that dnssec-policy is configured at the
right locations, and that policies referenced to in zone statements
actually exist.
Add some checks that when a user adds the new `dnssec-policy`
configuration, it will no longer contain existing DNSSEC
configuration options. Specifically: `inline-signing`,
`auto-dnssec`, `dnssec-dnskey-kskonly`, `dnssec-secure-to-insecure`,
`update-check-ksk`, `dnssec-update-mode`, `dnskey-sig-validity`,
and `sig-validity-interval`.
Test a good kasp configuration, and some bad configurations.
The ttlval configuration types are replaced by duration configuration
types. The duration is an ISO 8601 duration that is going to be used
for DNSSEC key timings such as key lifetimes, signature resign
intervals and refresh periods, etc. But it is also still allowed to
use the BIND ttlval ways of configuring intervals (number plus
optional unit).
A duration is stored as an array of 7 different time parts.
A duration can either be expressed in weeks, or in a combination of
the other datetime indicators.
Add several unit tests to ensure the correct value is parsed given
different string values.
glibc 2.30 deprecated the <sys/sysctl.h> header [1]. However, that
header is still used on other Unix-like systems, so only prevent it from
being used on Linux, in order to prevent compiler warnings from being
triggered.
[1] https://sourceware.org/ml/libc-alpha/2019-08/msg00029.html
When doing regular signing expiry time is jittered to make sure
that the re-signing times are not clumped together. This expands
this behaviour to expiry times of dynamically added records.
When incrementally re-signing a zone use the full jitter range if
the server appears to have been offline for greater than 5 minutes
otherwise use a small jitter range of 3600 seconds. This will stop
the signatures becoming more clustered if the server has been off
line for a significant period of time (> 5 minutes).
This variable will report the maximum number of simultaneous tcp clients
that BIND has served while running.
It can be verified by running rndc status, then inspect "tcp high-water:
count", or by generating statistics file, rndc stats, then inspect the
line with "TCP connection high-water" text.
The tcp-highwater variable is atomically updated based on an existing
tcp-quota system handled in ns/client.c.
Related scan-build report:
dnstap_test.c:169:2: warning: Value stored to 'result' is never read
result = dns_test_makeview("test", &view);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
dnstap_test.c:193:2: warning: Value stored to 'result' is never read
result = dns_compress_init(&cctx, -1, dt_mctx);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2 warnings generated.
If a TCP connection fails while attempting to send a query to a server,
the fetch context will be restarted without marking the target server as
a bad one. If this happens for a server which:
- was already marked with the DNS_FETCHOPT_EDNS512 flag,
- responds to EDNS queries with the UDP payload size set to 512 bytes,
- does not send response packets larger than 512 bytes,
and the response for the query being sent is larger than 512 byes, then
named will pointlessly alternate between sending UDP queries with EDNS
UDP payload size set to 512 bytes (which are responded to with truncated
answers) and TCP connections until the fetch context retry limit is
reached. Prevent such query loops by marking the server as bad for a
given fetch context if the advertised EDNS UDP payload size for that
server gets reduced to 512 bytes and it is impossible to reach it using
TCP.
cppcheck 1.89 emits a false positive for lib/dns/spnego_asn1.c:
lib/dns/spnego_asn1.c:698:9: error: Uninitialized variable: data [uninitvar]
memset(data, 0, sizeof(*data));
^
lib/dns/spnego.c:1707:47: note: Calling function 'decode_NegTokenResp', 3rd argument '&resp' value is <Uninit>
ret = decode_NegTokenResp(buf + taglen, len, &resp, NULL);
^
lib/dns/spnego_asn1.c:698:9: note: Uninitialized variable: data
memset(data, 0, sizeof(*data));
^
This message started appearing with cppcheck 1.89 [1], but it will be
gone in the next release [2], so just suppress it for the time being.
[1] af214e8212
[2] 2595b82634
cppcheck 1.89 enabled certain value flow analysis mechanisms [1] which
trigger null pointer dereference false positives in lib/dns/rpz.c:
lib/dns/rpz.c:582:7: warning: Possible null pointer dereference: tgt_ip [nullPointer]
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:1419:44: note: Calling function 'adj_trigger_cnt', 4th argument 'NULL' value is 0
adj_trigger_cnt(rpzs, rpz_num, rpz_type, NULL, 0, true);
^
lib/dns/rpz.c:582:7: note: Null pointer dereference
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:596:7: warning: Possible null pointer dereference: tgt_ip [nullPointer]
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:1419:44: note: Calling function 'adj_trigger_cnt', 4th argument 'NULL' value is 0
adj_trigger_cnt(rpzs, rpz_num, rpz_type, NULL, 0, true);
^
lib/dns/rpz.c:596:7: note: Null pointer dereference
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:610:7: warning: Possible null pointer dereference: tgt_ip [nullPointer]
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
lib/dns/rpz.c:1419:44: note: Calling function 'adj_trigger_cnt', 4th argument 'NULL' value is 0
adj_trigger_cnt(rpzs, rpz_num, rpz_type, NULL, 0, true);
^
lib/dns/rpz.c:610:7: note: Null pointer dereference
if (KEY_IS_IPV4(tgt_prefix, tgt_ip)) {
^
It seems that cppcheck no longer treats at least some REQUIRE()
assertion failures as fatal, so add extra assertion macro definitions to
lib/isc/include/isc/util.h that are only used when the CPPCHECK
preprocessor macro is defined; these definitions make cppcheck 1.89
behave as expected.
There is an important requirement for these custom definitions to work:
cppcheck must properly treat abort() as a function which does not
return. In order for that to happen, the __GNUC__ macro must be set to
a high enough number (because system include directories are used and
system headers compile attributes away if __GNUC__ is not high enough).
__GNUC__ is thus set to the major version number of the GCC compiler
used, which is what that latter does itself during compilation.
[1] aaeec462e6
BIND supports the non-standard DNSKEY algorithm mnemonic ECDSA256
everywhere ECDSAP256SHA256 is allowed, and allows algorithm numbers
interchangeably with mnemonics. This is all done in one place by the
dns_secalg_fromtext() function.
DS digest types were less consistent: the rdata parser does not allow
abbreviations like SHA1, but the dnssec-* command line tools do; and
the command line tools do not alow numeric types though that is the
norm in rdata.
The command line tools now use the dns_dsdigest_fromtext() function
instead of rolling their own variant, and dns_dsdigest_fromtext() now
knows about abbreviated digest type mnemonics.
