[PATCH 16/26] doc/admin-guide: update kernel.rst with CAP_PERFMON information

Arnaldo Carvalho de Melo
2020-04-13T16:53:46Z

From: Alexey Budankov <alexey.budankov@linux.intel.com>

Update the kernel.rst documentation file with the information related to
usage of CAP_PERFMON capability to secure performance monitoring and
observability operations in system.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-doc@vger.kernel.org
Cc: linux-man@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/84c32383-14a2-fa35-16b6-f9e59bd37240@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
Documentation/admin-guide/sysctl/kernel.rst | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 335696d3360d..aaa5bbcd1e33 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -709,7 +709,13 @@ perf_event_paranoid
===================

Controls use of the performance events system by unprivileged
-users (without CAP_SYS_ADMIN). The default value is 2.
+users (without CAP_PERFMON). The default value is 2.
+
+For backward compatibility reasons access to system performance
+monitoring and observability remains open for CAP_SYS_ADMIN
+privileged processes but CAP_SYS_ADMIN usage for secure system
+performance monitoring and observability operations is discouraged
+with respect to CAP_PERFMON use cases.

=== ==================================================================
-1 Allow use of (almost) all events by all users.
@@ -718,13 +724,13 @@ users (without CAP_SYS_ADMIN). The default value is 2.
``CAP_IPC_LOCK``.

>=0 Disallow ftrace function tracepoint by users without
- ``CAP_SYS_ADMIN``.
+ ``CAP_PERFMON``.

- Disallow raw tracepoint access by users without ``CAP_SYS_ADMIN``.
+ Disallow raw tracepoint access by users without ``CAP_PERFMON``.

->=1 Disallow CPU event access by users without ``CAP_SYS_ADMIN``.
+>=1 Disallow CPU event access by users without ``CAP_PERFMON``.

->=2 Disallow kernel profiling by users without ``CAP_SYS_ADMIN``.
+>=2 Disallow kernel profiling by users without ``CAP_PERFMON``.
=== ==================================================================

--
2.21.1