On 2/6/20 1:26 PM, Alexey Budankov wrote:
On 06.02.2020 21:23, Stephen Smalley wrote:
On 2/5/20 12:30 PM, Alexey Budankov wrote:
Introduce CAP_PERFMON capability designed to secure system performance
monitoring and observability operations so that CAP_PERFMON would assist
CAP_SYS_ADMIN capability in its governing role for performance monitoring
and observability subsystems.
CAP_PERFMON hardens system security and integrity during performance
monitoring and observability operations by decreasing attack surface that
is available to a CAP_SYS_ADMIN privileged process [2]. Providing the access
to system performance monitoring and observability operations under CAP_PERFMON
capability singly, without the rest of CAP_SYS_ADMIN credentials, excludes
chances to misuse the credentials and makes the operation more secure.
Thus, CAP_PERFMON implements the principal of least privilege for performance
monitoring and observability operations (POSIX IEEE 1003.1e: 2.2.2.39 principle
of least privilege: A security design principle that states that a process
or program be granted only those privileges (e.g., capabilities) necessary
to accomplish its legitimate function, and only for the time that such
privileges are actually required)
CAP_PERFMON meets the demand to secure system performance monitoring and
observability operations for adoption in security sensitive, restricted,
multiuser production environments (e.g. HPC clusters, cloud and virtual compute
environments), where root or CAP_SYS_ADMIN credentials are not available to
mass users of a system, and securely unblocks accessibility of system performance monitoring and observability operations beyond root and CAP_SYS_ADMIN use cases.
CAP_PERFMON takes over CAP_SYS_ADMIN credentials related to system performance
monitoring and observability operations and balances amount of CAP_SYS_ADMIN
credentials following the recommendations in the capabilities man page [1]
for CAP_SYS_ADMIN: "Note: this capability is overloaded; see Notes to kernel
developers, below." For backward compatibility reasons access to system
performance monitoring and observability subsystems of the kernel remains
open for CAP_SYS_ADMIN privileged processes but CAP_SYS_ADMIN capability
usage for secure system performance monitoring and observability operations
is discouraged with respect to the designed CAP_PERFMON capability.
Although the software running under CAP_PERFMON can not ensure avoidance
of related hardware issues, the software can still mitigate these issues
following the official hardware issues mitigation procedure [2]. The bugs
in the software itself can be fixed following the standard kernel development
process [3] to maintain and harden security of system performance monitoring
and observability operations.
[1] http://man7.org/linux/man-pages/man7/capabilities.7.html
[2] https://www.kernel.org/doc/html/latest/process/embargoed-hardware-issues.html
[3] https://www.kernel.org/doc/html/latest/admin-guide/security-bugs.html
Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
This will require a small update to the selinux-testsuite to correctly reflect the new capability requirements, but that's easy enough.
Is the suite a part of the kernel sources or something else?
It is external,
https://github.com/SELinuxProject/selinux-testsuite
I wasn't suggesting that your patch be blocked on updating the
testsuite, just noting that it will need to be done.
