[v1,1/2] doc/admin-guide: note credentials consolidation under CAP_PERFMON

Commit Message

Alexey Budankov Oct. 19, 2020, 5:16 p.m. UTC

Add note that starting from Linux v5.9 CAP_PERFMON Linux capability
is enough to conduct performance monitoring and observability using
perf_events API.

Signed-off-by: Alexey Budankov <[e-mail]>
---
 Documentation/admin-guide/perf-security.rst | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

Patch

diff --git a/Documentation/admin-guide/perf-security.rst b/Documentation/admin-guide/perf-security.rst
index 1307b5274a0f..57a65e27eeb9 100644
--- a/Documentation/admin-guide/perf-security.rst
+++ b/Documentation/admin-guide/perf-security.rst
@@ -84,11 +84,14 @@  capabilities then providing the process with CAP_PERFMON capability singly
 is recommended as the preferred secure approach to resolve double access
 denial logging related to usage of performance monitoring and observability.
 
-Unprivileged processes using perf_events system call are also subject
-for PTRACE_MODE_READ_REALCREDS ptrace access mode check [7]_ , whose
-outcome determines whether monitoring is permitted. So unprivileged
-processes provided with CAP_SYS_PTRACE capability are effectively
-permitted to pass the check.
+Prior Linux v5.9 unprivileged processes using perf_events system call
+are also subject for PTRACE_MODE_READ_REALCREDS ptrace access mode check
+[7]_ , whose outcome determines whether monitoring is permitted.
+So unprivileged processes provided with CAP_SYS_PTRACE capability are
+effectively permitted to pass the check. Starting from Linux v5.9
+CAP_SYS_PTRACE capability is not required and CAP_PERFMON is enough to
+be provided for processes to make performance monitoring and observability
+operations.
 
 Other capabilities being granted to unprivileged processes can
 effectively enable capturing of additional data required for later