p_can(...P_CAN_SEE...) to getpgid(), getsid(), and setpgid(),
blocking these operations on processes that should not be visible
by the requesting process. Required to reduce information leakage
in MAC environments.
Obtained from: TrustedBSD Project
from signal authorization checking.
o p_cansignal() takes three arguments: subject process, object process,
and signal number, unlike p_cankill(), which only took into account
the processes and not the signal number, improving the abstraction
such that CANSIGNAL() from kern_sig.c can now also be eliminated;
previously CANSIGNAL() special-cased the handling of SIGCONT based
on process session. privused is now deprecated.
o The new p_cansignal() further limits the set of signals that may
be delivered to processes with P_SUGID set, and restructures the
access control check to allow it to be extended more easily.
o These changes take into account work done by the OpenBSD Project,
as well as by Robert Watson and Thomas Moestl on the TrustedBSD
Project.
Obtained from: TrustedBSD Project
test by default, as setugid() is now part of the base kernel (assuming
(options REGRESSION) has been enabled for the running kernel).
Obtained from: TrustedBSD Project
toggle the P_SUGID bit explicitly, rather than relying on it being
set implicitly by other protection and credential logic. This feature
is introduced to support inter-process authorization regression testing
by simplifying userland credential management allowing the easy
isolation and reproduction of authorization events with specific
security contexts. This feature is enabled only by "options REGRESSION"
and is not intended to be used by applications. While the feature is
not known to introduce security vulnerabilities, it does allow
processes to enter previously inaccessible parts of the credential
state machine, and is therefore disabled by default. It may not
constitute a risk, and therefore in the future pending further analysis
(and appropriate need) may become a published interface.
Obtained from: TrustedBSD Project
interfaces and functionality intended for use during correctness and
regression testing. Features enabled by "options REGRESSION" may
in and of themselves introduce security or correctness problems if
used improperly, and so are not intended for use in production
systems, only in testing environments.
Obtained from: TrustedBSD Project
This test utility attempts to evaluate the current kernel policy
for authorization inter-process activities, currently ptrace(),
kill(, SIGHUP), getpriority(), and setpriority(). The utility creates
pairs of processes, initializes their credential sets to useful
cases, and reports on whether the results are in keeping with hard-coded
safety expectations.
o Currently, this utility relies on the availability of __setugid(),
an uncomitted system call used for managing the P_SUGID bit. Due to
continuing discussion of optional regression testing kernel components
("options REGRESSION") I'll hold off on committing that until the
discussion has reached its natural termination.
o A number of additional testing factors should be taken into account
in the testing, including tests for different classes of signals,
interactions with process session characteristics, I/O signalling,
broadcast activities such as broadcast signalling, mass priority
setting, and to take into group-related aspects of credentials.
Additional operations should also be taken into account, such as ktrace,
debugging attach using procfs, and so on.
o This testing suite is intended to prevent the introduction of bugs
in the upcoming sets of authorization changes associated with the
introduction of process capabilities and mandatory access control.
Obtained from: TrustedBSD Project
enable easy access to the hash chain stats. The raw prefixed versions
dump an integer array to userland with the chain lengths. This cheats
and calls it an array of 'struct int' rather than 'int' or sysctl -a
faithfully dumps out the 128K array on an average machine. The non-raw
versions return 4 integers: count, number of chains used, maximum chain
length, and percentage utilization (fixed point, multiplied by 100).
The raw forms are more useful for analyzing the hash distribution, while
the other form can be read easily by humans and stats loggers.
o Mention that the current environment is part of the -s calculation.
o Add a BUGS section that warns against executing a program that increases
the size of the argument list or the size of the environment.
I have wondered for a while what the difference is between
get a big list | xargs sudo command
which fails and
get a big list | sudo xargs command
which succeeds. The answer is that in the first case, sudo expands
the environment and pushes the amount of data passed into execve over
the E2BIG threshold.
API for IPI's that isn't tied to the Intel APIC. MD code can still use
the apic_ipi() function or dink with the apic directly if needed to send
MD IPI's.
