From: Joel Fernandes <joel@joelfernandes.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org,
primiano@google.com, rsavitski@google.com, jeffv@google.com,
kernel-team@android.com, Alexei Starovoitov <ast@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
bpf@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>,
Ingo Molnar <mingo@redhat.com>, James Morris <jmorris@namei.org>,
Jiri Olsa <jolsa@redhat.com>, Kees Cook <keescook@chromium.org>,
linux-security-module@vger.kernel.org,
Matthew Garrett <matthewgarrett@google.com>,
Namhyung Kim <namhyung@kernel.org>,
selinux@vger.kernel.org, Song Liu <songliubraving@fb.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, Yonghong Song <yhs@fb.com>
Subject: Re: [PATCH RFC] perf_event: Add support for LSM and SELinux checks
Date: Fri, 11 Oct 2019 11:47:34 -0400 [thread overview]
Message-ID: <20191011154734.GA105106@google.com> (raw)
In-Reply-To: <20191011070543.GV2328@hirez.programming.kicks-ass.net>
On Fri, Oct 11, 2019 at 09:05:43AM +0200, Peter Zijlstra wrote:
> On Thu, Oct 10, 2019 at 02:31:14PM -0400, Joel Fernandes wrote:
> > On Thu, Oct 10, 2019 at 07:09:49PM +0200, Peter Zijlstra wrote:
>
> > > Yes, I did notice, I found it weird.
> > >
> > > If you have CAP_IPC_LIMIT you should be able to bust mlock memory
> > > limits, so I don't see why we should further relate that to paranoid.
> > >
> > > The way I wrote it, we also allow to bust the limit if we have disabled
> > > all paranoid checks. Which makes some sense I suppose.
> > >
> > > The original commit is this:
> > >
> > > 459ec28ab404 ("perf_counter: Allow mmap if paranoid checks are turned off")
> >
> > I am thinking we can just a new function perf_is_paranoid() that has nothing
> > to do with the CAP_SYS_ADMIN check and doesn't have tracepoint wording:
> >
> > static inline int perf_is_paranoid(void)
> > {
> > return sysctl_perf_event_paranoid > -1;
> > }
> >
> > And then call that from the mmap() code:
> > if (locked > lock_limit && perf_is_paranoid() && !capable(CAP_IPC_LOCK)) {
> > return -EPERM;
> > }
> >
> > I don't think we need to add selinux security checks here since we are
> > already adding security checks earlier in mmap(). This will make the code and
> > its intention more clear and in line with the commit 459ec28ab404 you
> > mentioned. Thoughts?
>
> Mostly that I'm confused by the current code ;-)
>
> Like I said, CAP_IPC_LIMIT on its own should already allow busting the
> limit, I don't really see why we should make it conditional on paranoid.
>
> But if you want to preserve behaviour (arguably a sane thing for your
> patch) then yes, feel free to do as you propose.
Ok, I will do it as I proposed above and resend patch today. Thanks!
- Joel
prev parent reply other threads:[~2019-10-11 15:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 20:36 [PATCH RFC] perf_event: Add support for LSM and SELinux checks Joel Fernandes (Google)
2019-10-09 21:55 ` Casey Schaufler
2019-10-09 22:14 ` James Morris
2019-10-09 22:41 ` Casey Schaufler
2019-10-10 0:40 ` Joel Fernandes
2019-10-10 0:53 ` Casey Schaufler
2019-10-10 2:44 ` James Morris
2019-10-10 18:12 ` Casey Schaufler
2019-10-10 19:41 ` James Morris
2019-10-09 22:11 ` James Morris
2019-10-10 0:43 ` Joel Fernandes
2019-10-10 7:23 ` Alexey Budankov
2019-10-10 8:12 ` Peter Zijlstra
2019-10-10 15:13 ` Joel Fernandes
2019-10-10 17:09 ` Peter Zijlstra
2019-10-10 18:31 ` Joel Fernandes
2019-10-11 7:05 ` Peter Zijlstra
2019-10-11 15:47 ` Joel Fernandes [this message]
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=20191011154734.GA105106@google.com \
--to=joel@joelfernandes.org \
--cc=acme@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=jeffv@google.com \
--cc=jmorris@namei.org \
--cc=jolsa@redhat.com \
--cc=keescook@chromium.org \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=matthewgarrett@google.com \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
--cc=primiano@google.com \
--cc=rostedt@goodmis.org \
--cc=rsavitski@google.com \
--cc=selinux@vger.kernel.org \
--cc=songliubraving@fb.com \
--cc=x86@kernel.org \
--cc=yhs@fb.com \
/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).