From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: linux-man@vger.kernel.org, James Morris <jmorris@namei.org>,
Serge Hallyn <serge@hallyn.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
Peter Zijlstra <peterz@infradead.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andi Kleen <ak@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: [PATCH v1] perf_event_open.2: update the man page with CAP_PERFMON related information
Date: Mon, 17 Feb 2020 11:18:55 +0300 [thread overview]
Message-ID: <18d1083d-efe5-f5f8-c531-d142c0e5c1a8@linux.intel.com> (raw)
Extend perf_event_open 2 man page with the information about
CAP_PERFMON capability designed to secure performance monitoring
and observability operation in a system according to the principle
of least privilege [1] (POSIX IEEE 1003.1e, 2.2.2.39).
[1] https://sites.google.com/site/fullycapable/, posix_1003.1e-990310.pdf
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
man2/perf_event_open.2 | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 89d267c02..e9aab2ca1 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -98,6 +98,8 @@ when running on the specified CPU.
.BR "pid == \-1" " and " "cpu >= 0"
This measures all processes/threads on the specified CPU.
This requires
+.B CAP_PERFMON
+or
.B CAP_SYS_ADMIN
capability or a
.I /proc/sys/kernel/perf_event_paranoid
@@ -2920,6 +2922,8 @@ to hold the result.
This allows attaching a Berkeley Packet Filter (BPF)
program to an existing kprobe tracepoint event.
You need
+.B CAP_PERFMON
+or
.B CAP_SYS_ADMIN
privileges to use this ioctl.
.IP
@@ -2962,6 +2966,8 @@ have multiple events attached to a tracepoint.
Querying this value on one tracepoint event returns the id
of all BPF programs in all events attached to the tracepoint.
You need
+.B CAP_PERFMON
+or
.B CAP_SYS_ADMIN
privileges to use this ioctl.
.IP
@@ -3170,6 +3176,8 @@ it was expecting.
.TP
.B EACCES
Returned when the requested event requires
+.B CAP_PERFMON
+or
.B CAP_SYS_ADMIN
permissions (or a more permissive perf_event paranoid setting).
Some common cases where an unprivileged process
@@ -3291,6 +3299,8 @@ setting is specified.
It can also happen, as with
.BR EACCES ,
when the requested event requires
+.B CAP_PERFMON
+or
.B CAP_SYS_ADMIN
permissions (or a more permissive perf_event paranoid setting).
This includes setting a breakpoint on a kernel address,
@@ -3321,6 +3331,23 @@ The official way of knowing if
support is enabled is checking
for the existence of the file
.IR /proc/sys/kernel/perf_event_paranoid .
+.PP
+.B CAP_PERFMON
+capability (since Linux X.Y) provides secure approach to
+performance monitoring and observability operations in a system
+according to the principal of least privilege (POSIX IEEE 1003.1e).
+Accessing system performance monitoring and observability operations
+using
+.B CAP_PERFMON
+capability singly, without the rest of
+.B CAP_SYS_ADMIN
+credentials, excludes chances to misuse the credentials and makes
+the operations more secure.
+.B CAP_SYS_ADMIN
+usage for secure system performance monitoring and observability
+is discouraged with respect to
+.B CAP_PERFMON
+capability.
.SH BUGS
The
.B F_SETOWN_EX
--
2.20.1
next reply other threads:[~2020-02-17 8:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-17 8:18 Alexey Budankov [this message]
2020-08-23 17:28 ` [PATCH v1] perf_event_open.2: update the man page with CAP_PERFMON related information Michael Kerrisk (man-pages)
2020-08-24 20:17 ` Alexey Budankov
2020-10-27 9:25 ` Michael Kerrisk (man-pages)
2020-10-27 10:34 ` Alexey Budankov
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