o Introduce new kern.security sysctl tree for kernel security policy
MIB entries.
o Relocate kern.suser_permitted to kern.security.suser_permitted.
o Introduce new kern.security.unprivileged_procdebug_permitted, which
(when set to 0) prevents processes without privilege from performing a variety of inter-process debugging activities. The default is 1, to provide current behavior. This feature allows "hardened" systems to disable access to debugging facilities, which have been associated with a number of past security vulnerabilities. Previously, while procfs could be unmounted, other in-kernel facilities (such as ptrace()) were still available. This setting should not be modified on normal development systems, as it will result in frustration. Some utilities respond poorly to failing to get the debugging access they require, and error response by these utilities may be improved in the future in the name of beautification. Note that there are currently some odd interactions with some facilities, which will need to be resolved before this should be used in production, including odd interactions with truss and ktrace. Note also that currently, tracing is permitted on the current process regardless of this flag, for compatibility with previous authorization code in various facilities, but that will probably change (and resolve the odd interactions).
Obtained from: TrustedBSD Project