[PATCH v7 12/12] doc/admin-guide: update kernel.rst with CAP_PERFMON information

From: Alexey Budankov
Date: Mon Feb 17 2020 - 03:13:51 EST



Update 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@xxxxxxxxxxxxxxx>
---
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 def074807cee..b06ae9389809 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -720,20 +720,26 @@ 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

Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK

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


--
2.20.1