Instead of selectively suspending logging by redirecting messages to
/dev/null, increase the default minimum log severity to FATAL. In the
debug mode, all messages are printed.
In the NTS-NTP client instance, maintain a local copy of the NTP address
instead of using a pointer to the NCR's address, which may change at
unexpected times.
Also, change the NNC_CreateInstance() to accept only the NTP port to
make it clear the initial NTP address is the same as the NTS-KE address
and to make it consistent with NNC_ChangeAddress(), which accepts only
one address.
Remove stratum from the NTP sample and update it together with the leap
status. This enables a faster update when samples are dropped by the NTP
filters.
Remove packet interval checks with long delays as the tests are much
more likely to end when the client is waiting for a response. Increase
the base delay to make selection with two sources more reliable.
Reported-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Don't accept NTPv4 packets which have a MAC longer than 24 octets to
strictly follow RFC 7822, which specifies the maximum length of a MAC
and the minimum length of the last extension field to avoid an ambiguity
in parsing of the packet.
This removes an ugly hack that was needed to accept packets that
contained one or more extension fields without a MAC, before RFC 7822
was written and NTP implementations started using truncated MACs.
The long MACs were used by chrony in versions 2.x when configured to
authenticate a server or peer with a key using a 256-bit or longer hash
(e.g. SHA256). For compatibility with chrony >= 4.0, these clients/peers
will need to have "version 3" added to the server/peer line in
chrony.conf.
When the request has an unrecognized critical record before the
NEXT_PROTOCOL and AEAD_ALGORITHM records, respond with error 0
(unrecognized critical record) instead of 1 (bad request).
When the request has multiple NEXT_PROTOCOL or AEAD_ALGORITHM records,
respond with error 1 (bad request).
For consistency and safety, change the CMC and HSH functions to accept
signed lengths and handle negative values as errors. Also, change the
input data type to void * to not require casting in the caller.
The daemon transmit timestamps are precompensated for the time it takes
to generate a MAC using a symmetric key (as measured on chronyd start)
and also an average round-trip time of the Samba signing of MS-SNTP
responses. This improves accuracy of the transmit timestamp, but it
has some issues.
The correction has a random error which is changing over time due to
variable CPU frequency, system load, migration to a different machine,
etc. If the measured delay is too large, the correction may cause the
transmit timestamp to be later than the actual transmission. Also, the
delay is measured for a packet of a minimal length with no extension
fields, and there is no support for NTS.
Drop the precompensation in favor of the interleaved mode, which now
avoids the authentication delay even when no kernel/hardware timestamps
are available.
Allow an IP family to be specified in the socket initialization in order
to globally disable the other family. This replaces the ntp_io and
cmdmon code handling the -4/-6 options and fixes a case where the NTP
client could still use a disabled family if the source was specified
with an IP address.
When the main makefile is used to get the list of chronyd objects in
order to build the unit tests, clang started (with the -MM option) to
generate the dependency files prints error messages about wrong
inclusions. Set a NODEPS variable to completely disable the generation
of the files.
When compiled with NTS support, don't require a SIV cipher to be always
supported (e.g. due to a different version of a library used for
building). Handle this case with a fatal message instead of crash.
Also, check the support early in the client unit test to prevent a hang.
Handle trusted sources as a separate set of sources which is required to
have a majority for the selection to proceed. This should improve the
selection with multiple trusted sources (e.g. due to the auth selection
mode).
Destroy the client cert credentials when destroying the last NKC
instance instead of NKC_Finalise(). This allows the client to reload the
trusted cert file between NTS-KE sessions.
Instead of sharing the NTP rate limiting with NTS-KE, specify a new
service for NTS-KE and use it in the NTS-KE server.
Add ntsratelimit directive for configuration.
Refactor the client record and clientlog API to reuse more code between
different services and enumerate the services instead of hardcoding NTP
and cmdmon.
When authentication is enabled for an NTP source, unauthenticated NTP
sources need to be disabled or limited in selection. That might be
difficult to do when the configuration comes from different sources
(e.g. networking scripts adding servers from DHCP).
Define four modes for the source selection to consider authentication:
require, prefer, mix, ignore. In different modes different selection
options (require, trust, noselect) are added to authenticated and
unauthenticated sources.
The mode can be selected by the authselectmode directive. The mix mode
is the default. The ignore mode enables the old behavior, where all
sources are used exactly as specified in the configuration.
Refactor the code to allow the selection options of the current sources
to be modified when other sources are added and removed. Also, make the
authentication status of each source available to the code which makes
the modifications.
Add "nocerttimecheck" directive to specify the number of clock updates
that need to be made before the time validation of certificates is
enabled. This makes NTS usable on machines that don't have a RTC.
Add a context structure for the algorithm and keys established by
NTS-KE. Modify the client to save the context and reset the SIV key to
the C2S/S2C key before each request/response instead of keeping two SIV
instances.
This will make it easier for the server to support different algorithms
and allow the client to save the context with cookies to disk.
Make the NTS-KE retry interval exponentially increasing, using a factor
provided by the NKE session. Use shorter intervals when the server is
refusing TCP connections or the connection is closed or timing out
before the TLS handshake.
The server session instances are reused for different clients. Separate
the server name from the label used in log messages and set it on each
start of the session.
Remove leap status from the NTP sample and set it independently from
the sample accumulation in order to accept a leap second sooner when
samples are filtered.
The reset command drops all measurements and switches the reference to
the unsynchronised state. This command can help chronyd with recovery
when the measurements are known to be no longer valid or accurate, e.g.
due to moving the computer to a different network, or resuming the
computer from a low-power state (which resets the system clock).
If authentication is not enabled in configuration, responses are not
expected to be authenticated. Handle such responses as having failed
authentication.
A case where this could happen is a misconfigured symmetric association
where only one peer has specified the other with a key. Before this
change synchronization would work in one direction and used packets
with an asymmetric length.
Add -a option to the sources and sourcestats commands to print all
sources, including those that don't have a resolved address yet. By
default, only sources that have a real address are printed for
compatibility. Remove the "210 Number of sources" messages to avoid
confusion. Also, modify the ntpdata command to always print only sources
with a resolved address.
The current default NTP era split passed the Unix epoch (~50 years ago),
which means the epoch converted to an NTP timestamp and back ends up in
the next NTP era (year 2106).
Fix the test to take into account the era split.
The test might run on different platforms. If the platform happens
to have a RTC that does exist but unable to have RTC_UIE_ON set the
test will fail, while the chrony code is actually good.
Examples of bad clocks are:
- ppc64el: rtc-generic
- arm64: rtc-efi
To avoid that extend the log message check on 101-rtc to accept
that condition as a valid test result as well.
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
An analysis by Tim Ruffing [1] shows that a length extension attack
adding valid extension fields to NTPv4 packets is possible with some
specific key lengths and hash functions using little-endian length like
MD5 and RIPEMD160.
chronyd currently doesn't process or generate any extension fields, but
it could be a problem in future when a non-authentication extension
field is supported.
Drop support for all RIPEMD functions as they don't seem to be secure in
the context of the NTPv4 MAC. MD5 is kept only for compatibility.
[1] https://mailarchive.ietf.org/arch/msg/ntp/gvibuB6bTbDRBumfHNdJ84Kq4kA
In the local reference mode, instead of returning the adjusted current
time as the reference time, return the same timestamp updated only once
per about 62.5 seconds.
This will enable chronyd to detect polling of itself even when the local
reference mode is active.
Add a new set of tests for testing basic functionality, starting chronyd
with root privileges on the actual system instead of the simulator.
Tests numbered in the 100-199 range are considered destructive and
intended to be used only on machines dedicated for development or
testing. They are started by the run script only with the -d option.
They may adjust/step the system clock and other clocks, block the RTC,
enable HW timestamping, create SHM segments, etc.
Other tests should not interfere with the system and should work even
when another NTP server/client is running.
