7e8eda734d
Emit an audit record every time selected NTP parameters are modified
from userspace (via adjtimex(2) or clock_adjtime(2)). These parameters
may be used to indirectly change system clock, and thus their
modifications should be audited.
Such events will now generate records of type AUDIT_TIME_ADJNTPVAL
containing the following fields:
- op -- which value was adjusted:
- offset -- corresponding to the time_offset variable
- freq -- corresponding to the time_freq variable
- status -- corresponding to the time_status variable
- adjust -- corresponding to the time_adjust variable
- tick -- corresponding to the tick_usec variable
- tai -- corresponding to the timekeeping's TAI offset
- old -- the old value
- new -- the new value
Example records:
type=TIME_ADJNTPVAL msg=audit(1530616044.507:7): op=status old=64 new=8256
type=TIME_ADJNTPVAL msg=audit(1530616044.511:11): op=freq old=0 new=49180377088000
The records of this type will be associated with the corresponding
syscall records.
An overview of parameter changes that can be done via do_adjtimex()
(based on information from Miroslav Lichvar) and whether they are
audited:
__timekeeping_set_tai_offset() -- sets the offset from the
International Atomic Time
(AUDITED)
NTP variables:
time_offset -- can adjust the clock by up to 0.5 seconds per call
and also speed it up or slow down by up to about
0.05% (43 seconds per day) (AUDITED)
time_freq -- can speed up or slow down by up to about 0.05%
(AUDITED)
time_status -- can insert/delete leap seconds and it also enables/
disables synchronization of the hardware real-time
clock (AUDITED)
time_maxerror, time_esterror -- change error estimates used to
inform userspace applications
(NOT AUDITED)
time_constant -- controls the speed of the clock adjustments that
are made when time_offset is set (NOT AUDITED)
time_adjust -- can temporarily speed up or slow down the clock by up
to 0.05% (AUDITED)
tick_usec -- a more extreme version of time_freq; can speed up or
slow down the clock by up to 10% (AUDITED)
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.