When the burst option is specified in the server/pool directive and the
current poll is longer than the minimum poll, initiate on each poll a
burst with 1 good sample and 2 or 4 total samples according to the
difference between the current and minimum poll.
Before reading the n_samples field of the MANUAL_LIST reply, check if it
is actually contained in the received message. This does not change the
outcome of the client's length check as the returned length was always
larger than the length of the truncated reply and it was dropped anyway,
but it prevents the client from reading uninitialized memory.
It was never used for anything and messages in debug output already
include filenames, which can be easily grepped if there is a need
to see log messages only from a particular file.
Add xleave option to the peer directive to enable an interleaved mode
compatible with ntpd. This allows peers to exchange transmit timestamps
captured after the actual transmission and significantly improve
the accuracy of the measurements.
Replace struct timeval with struct timespec as the main data type for
timestamps. This will allow the NTP code to work with timestamps in
nanosecond resolution.
Replace SCH_*InputFileHandler() functions with more general
SCH_*FileHandler(), where events are specified as a new parameter and
which will later support other file events, e.g. file ready for ouput
and exception.
The file handlers have two new parameters: file descriptor and event.
There was an incompatible change in the client access report. To avoid
bumping the protocol version drop support for the original request/reply
types and define new CLIENT_ACCESSES_BY_INDEX2 types as a newer version
of the command.
The clientlog record still uses 16-bit integers to count dropped
packets, but this will avoid an incompatible change in the command
reply if there will be a need to count more than 2^16 drops.
Require that at least one of the sources specified with this option is
selectable (i.e. recently reachable and not a falseticker) before
updating the clock. Together with the trust option this may be useful to
allow a trusted, but not very precise, reference clock or a trusted
authenticated NTP source to be safely combined with unauthenticated NTP
sources in order to improve the accuracy of the clock. They can be
selected and used for synchronization only if they agree with the
trusted and required source.
Assume time from a source that is specified with the trust option is
always true. It can't be rejected as falseticker in the source
selection if sources that are specified without this option don't agree
with it.
Instead of time_t use a 32-bit fixed point representation with 4-bit
fraction to save the time of the last hit. The rate can now be measured
up to 16 packets per second. Maximum interval between hits is about 4
years.
Add new fields from clientlog to the report and print them in chronyc.
Rework the code to skip empty records in the hash table. The reply no
longer has variable length, all client fields are filled even if some
are empty. Reply with RPY_NULL when the facility is disabled.
When the measured NTP or command request rate of a client exceeds
a threshold, reply only to a small fraction of the requests to reduce
the network traffic. Clients are allowed to send a burst of requests.
Try to detect broken clients which increase the request rate when not
getting replies and suppress the rate limiting for them.
Add ratelimit and cmdratelimit directives to configure the thresholds,
bursts and leak rates independently for NTP and command response rate
limiting. Both are disabled by default. Commands from localhost are
never limited.
Don't log NTP peer access and auth/bad command access. Also, change
types for logging number of hits from long to uint32_t. This reduces the
size of the node and allows more clients to be monitored in the same
amount of memory.
Call the CAM, NIO, NCR initialization functions and setup the access
restrictions before root is dropped. This will be needed on NetBSD,
where it's not possible to bind sockets to privileged ports without the
root privileges. Split the creation of the Unix domain command socket
from the CAM initialization to keep the chrony user as the owner of the
socket.
With the new support for cmdmon over Unix domain sockets, authentication
is no longer necessary to authorize a client running on localhost with
the permissions of the root or chrony user/group. Remove the cmdmon
authentication support to simplify the code and significantly reduce the
attack surface of the protocol.
Only monitoring commands are now allowed remotely. Users that need to
configure chronyd remotely or locally without root/chrony permissions
are advised to use ssh and/or sudo.
Allow all commands received from the Unix domain command socket (which
is accessible only by the root and chrony user/group), even when they
are not authenticated with the command key.
In addition to the IPv4/IPv6 command sockets, create also a Unix domain
socket to process cmdmon requests. For now, there is no difference for
authorized commands, packets from all sockets need to be authenticated.
The default path of the socket is /var/run/chrony/chronyd.sock. It can
be configured with the bindcmdaddress directive with an address starting
with /.
The second form configures the automatic stepping, similarly to the
makestep directive. It has two parameters, stepping threshold (in
seconds) and number of future clock updates for which will be the
threshold active. This can be used with the burst command to quickly
make a new measurement and correct the clock by stepping if needed,
without waiting for chronyd to complete the measurement and update the
clock.
The next pointer in the last allocated reply slot was not set. This
could cause a crash when more slots were needed. (the slots are used to
save unacknowledged replies to authenticated commands)
Rework makestep to cancel accumulated offset and step with the new
offset instead of accumulating new offset first, canceling all
accumulated offset and making the step.
This avoids two large frequency changes to initiate and cancel a slew
before making the step.
The status codes STT_BADPKTVERSION, STT_BADPKTLENGTH, STT_NOHOSTACCESS
were sent even to hosts that were not allowed by cmdallow. Deprecate
STT_NOHOSTACCESS and ignore packets from hosts not allowed by cmdallow
completely.
To prevent an attacker using chronyd in an amplification attack, change
the protocol to include padding in request packets so that the largest
possible reply is not larger than the request. Request packets that
don't include this padding are ignored as invalid.
This is an incompatible change in the protocol. Clients from chrony
1.27, 1.28 and 1.29 will receive NULL reply with STT_BADPKTVERSION and
print "Protocol version mismatch". Clients from 1.26 and older will not
receive a reply as it would be larger than the request if it was padded
to be compatible with their protocol.
Support for the SUBNETS_ACCESSED and CLIENT_ACCESSES commands was
enabled in chronyd, but in chronyc it was always disabled and the
CLIENT_ACCESSES_BY_INDEX command was used instead. As there is no plan
to enable it in the future, remove the support completely.
The RPY_SUBNETS_ACCESSED and RPY_CLIENT_ACCESSES command replies can
contain uninitalized data from stack when the client logging is disabled
or a bad subnet is requested. These commands were never used by chronyc
and they require the client to be authenticated since version 1.25.
When the length of the REQ_SUBNETS_ACCESSED, REQ_CLIENT_ACCESSES
command requests and the RPY_SUBNETS_ACCESSED, RPY_CLIENT_ACCESSES,
RPY_CLIENT_ACCESSES_BY_INDEX, RPY_MANUAL_LIST command replies is
calculated, the number of items stored in the packet is not validated.
A crafted command request/reply can be used to crash the server/client.
Only clients allowed by cmdallow (by default only localhost) can crash
the server.
With chrony versions 1.25 and 1.26 this bug has a smaller security
impact as the server requires the clients to be authenticated in order
to process the subnet and client accesses commands. In 1.27 and 1.28,
however, the invalid calculated length is included also in the
authentication check which may cause another crash.
Combine only sources whose distance is shorter than distance of the
selected source multiplied by the value of combinelimit and their
estimated frequencies are close to the frequency of the selected source.
Add outlyer status for sources which are selectable, but not included in
the combining. The status is displayed as '-' in the chronyc sources
output.
- normalize command line before parsing
- compare whole words
- check for missing/extra arguments in config parsing
- use strdup for string allocation
- share code for reporting syntax errors
- avoid using function pointers
- cleanup the code a bit
We want to correct the offset quickly, but we also want to keep the
frequency error caused by the correction itself low.
Define correction rate as the area of the region bounded by the graph of
offset corrected in time. Set the rate so that the time needed to correct
an offset equal to the current sourcestats stddev will be equal to the
update interval (assuming linear adjustment). The offset and the
time needed to make the correction are inversely proportional.
This is only a suggestion and it's up to the system driver how the
adjustment will be executed.
Allow different hash functions to be used in the NTP and cmdmon
protocols. This breaks the cmdmon protocol compatibility. Extended key
file format is used to specify the hash functions for chronyd and new
authhash command is added to chronyc. MD5 is the default and the only
function included in the chrony source code, other functions will be
available from libraries.
