From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
To: Alexey Budankov <alexey.budankov@linux.intel.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: Re: [PATCH v1] perf_event_open.2: update the man page with CAP_PERFMON related information
Date: Sun, 23 Aug 2020 19:28:31 +0200 [thread overview]
Message-ID: <ed6f63bd-5dcb-425d-60ee-311a68756bfe@gmail.com> (raw)
In-Reply-To: <18d1083d-efe5-f5f8-c531-d142c0e5c1a8@linux.intel.com>
Hello Alexey,
Could you look at the question below and update the patch.
On 2/17/20 9:18 AM, Alexey Budankov wrote:
>
> 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
What's the version?
> +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
I think that wording like "using CAP_PERFMON rather than the much
more powerful CAP_SYS_ADMIN..."
> +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
Thanks,
Michael
next prev parent reply other threads:[~2020-08-23 17:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-17 8:18 [PATCH v1] perf_event_open.2: update the man page with CAP_PERFMON related information Alexey Budankov
2020-08-23 17:28 ` Michael Kerrisk (man-pages) [this message]
2020-08-24 20:17 ` Alexey Budankov
2020-10-27 9:25 ` Michael Kerrisk (man-pages)
2020-10-27 10:34 ` Alexey Budankov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ed6f63bd-5dcb-425d-60ee-311a68756bfe@gmail.com \
--to=mtk.manpages@gmail.com \
--cc=acme@kernel.org \
--cc=ak@linux.intel.com \
--cc=alexey.budankov@linux.intel.com \
--cc=jmorris@namei.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-man@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=sds@tycho.nsa.gov \
--cc=serge@hallyn.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).