From: Jiri Olsa <jolsa@redhat.com> To: Daniel Borkmann <daniel@iogearbox.net> Cc: Paul Moore <paul@paul-moore.com>, Ondrej Mosnacek <omosnace@redhat.com>, linux-security-module@vger.kernel.org, James Morris <jmorris@namei.org>, Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>, Stephen Smalley <stephen.smalley.work@gmail.com>, selinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Casey Schaufler <casey@schaufler-ca.com>, andrii.nakryiko@gmail.com Subject: Re: [PATCH v2] lockdown,selinux: avoid bogus SELinux lockdown permission checks Date: Fri, 28 May 2021 12:16:11 +0200 [thread overview] Message-ID: <YLDC6zQUtoITdX4s@krava> (raw) In-Reply-To: <4fee8c12-194f-3f85-e28b-f7f24ab03c91@iogearbox.net> On Fri, May 28, 2021 at 11:56:02AM +0200, Daniel Borkmann wrote: SNIP > > Ondrej / Paul / Jiri: at least for the BPF tracing case specifically (I haven't looked > at the rest but it's also kind of independent), the attached fix should address both > reported issues, please take a look & test. > > Thanks a lot, > Daniel > From 5893ad528dc0a0a68933b8f2a81b18d3f539660d Mon Sep 17 00:00:00 2001 > From: Daniel Borkmann <daniel@iogearbox.net> > Date: Fri, 28 May 2021 09:16:31 +0000 > Subject: [PATCH bpf] bpf, audit, lockdown: Fix bogus SELinux lockdown permission checks > > Commit 59438b46471a ("security,lockdown,selinux: implement SELinux lockdown") > added an implementation of the locked_down LSM hook to SELinux, with the aim > to restrict which domains are allowed to perform operations that would breach > lockdown. This is indirectly also getting audit subsystem involved to report > events. The latter is problematic, as reported by Ondrej and Serhei, since it > can bring down the whole system via audit: > > i) The audit events that are triggered due to calls to security_locked_down() > can OOM kill a machine, see below details [0]. > > ii) It seems to be causing a deadlock via slow_avc_audit() -> audit_log_end() > when presumingly trying to wake up kauditd [1]. > > Fix both at the same time by taking a completely different approach, that is, > move the check into the program verification phase where we actually retrieve > the func proto. This also reliably gets the task (current) that is trying to > install the tracing program, e.g. bpftrace/bcc/perf/systemtap/etc, and it also > fixes the OOM since we're moving this out of the BPF helpers which can be called > millions of times per second. nice idea.. I'll try to reproduce and test jirka
WARNING: multiple messages have this Message-ID (diff)
From: Jiri Olsa <jolsa@redhat.com> To: Daniel Borkmann <daniel@iogearbox.net> Cc: Paul Moore <paul@paul-moore.com>, selinux@vger.kernel.org, netdev@vger.kernel.org, Stephen Smalley <stephen.smalley.work@gmail.com>, James Morris <jmorris@namei.org>, Steven Rostedt <rostedt@goodmis.org>, Ondrej Mosnacek <omosnace@redhat.com>, Casey Schaufler <casey@schaufler-ca.com>, linux-security-module@vger.kernel.org, Ingo Molnar <mingo@redhat.com>, linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, andrii.nakryiko@gmail.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] lockdown,selinux: avoid bogus SELinux lockdown permission checks Date: Fri, 28 May 2021 12:16:11 +0200 [thread overview] Message-ID: <YLDC6zQUtoITdX4s@krava> (raw) In-Reply-To: <4fee8c12-194f-3f85-e28b-f7f24ab03c91@iogearbox.net> On Fri, May 28, 2021 at 11:56:02AM +0200, Daniel Borkmann wrote: SNIP > > Ondrej / Paul / Jiri: at least for the BPF tracing case specifically (I haven't looked > at the rest but it's also kind of independent), the attached fix should address both > reported issues, please take a look & test. > > Thanks a lot, > Daniel > From 5893ad528dc0a0a68933b8f2a81b18d3f539660d Mon Sep 17 00:00:00 2001 > From: Daniel Borkmann <daniel@iogearbox.net> > Date: Fri, 28 May 2021 09:16:31 +0000 > Subject: [PATCH bpf] bpf, audit, lockdown: Fix bogus SELinux lockdown permission checks > > Commit 59438b46471a ("security,lockdown,selinux: implement SELinux lockdown") > added an implementation of the locked_down LSM hook to SELinux, with the aim > to restrict which domains are allowed to perform operations that would breach > lockdown. This is indirectly also getting audit subsystem involved to report > events. The latter is problematic, as reported by Ondrej and Serhei, since it > can bring down the whole system via audit: > > i) The audit events that are triggered due to calls to security_locked_down() > can OOM kill a machine, see below details [0]. > > ii) It seems to be causing a deadlock via slow_avc_audit() -> audit_log_end() > when presumingly trying to wake up kauditd [1]. > > Fix both at the same time by taking a completely different approach, that is, > move the check into the program verification phase where we actually retrieve > the func proto. This also reliably gets the task (current) that is trying to > install the tracing program, e.g. bpftrace/bcc/perf/systemtap/etc, and it also > fixes the OOM since we're moving this out of the BPF helpers which can be called > millions of times per second. nice idea.. I'll try to reproduce and test jirka
next prev parent reply other threads:[~2021-05-28 10:16 UTC|newest] Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-17 9:20 [PATCH v2] lockdown,selinux: avoid bogus SELinux lockdown permission checks Ondrej Mosnacek 2021-05-17 9:20 ` [PATCH v2] lockdown, selinux: " Ondrej Mosnacek 2021-05-17 11:00 ` [PATCH v2] lockdown,selinux: " Michael Ellerman 2021-05-17 11:00 ` Michael Ellerman 2021-05-26 11:44 ` Ondrej Mosnacek 2021-05-26 11:44 ` Ondrej Mosnacek 2021-05-27 4:28 ` James Morris 2021-05-27 4:28 ` James Morris 2021-05-27 14:18 ` Paul Moore 2021-05-27 14:18 ` Paul Moore 2021-05-28 1:37 ` Paul Moore 2021-05-28 1:37 ` Paul Moore 2021-05-28 7:09 ` Daniel Borkmann 2021-05-28 7:09 ` Daniel Borkmann 2021-05-28 9:53 ` Jiri Olsa 2021-05-28 9:53 ` Jiri Olsa 2021-05-28 9:56 ` Daniel Borkmann 2021-05-28 9:56 ` Daniel Borkmann 2021-05-28 10:16 ` Jiri Olsa [this message] 2021-05-28 10:16 ` Jiri Olsa 2021-05-28 11:47 ` Jiri Olsa 2021-05-28 11:47 ` Jiri Olsa 2021-05-28 11:54 ` Daniel Borkmann 2021-05-28 11:54 ` Daniel Borkmann 2021-05-28 13:42 ` Ondrej Mosnacek 2021-05-28 13:42 ` Ondrej Mosnacek 2021-05-28 14:20 ` Daniel Borkmann 2021-05-28 14:20 ` Daniel Borkmann 2021-05-28 15:54 ` Paul Moore 2021-05-28 15:54 ` Paul Moore 2021-05-28 15:47 ` Paul Moore 2021-05-28 15:47 ` Paul Moore 2021-05-28 18:10 ` Daniel Borkmann 2021-05-28 18:10 ` Daniel Borkmann 2021-05-28 22:52 ` Paul Moore 2021-05-28 22:52 ` Paul Moore 2021-05-29 18:48 ` Paul Moore 2021-05-29 18:48 ` Paul Moore 2021-05-31 8:24 ` Daniel Borkmann 2021-05-31 8:24 ` Daniel Borkmann 2021-06-01 20:47 ` Paul Moore 2021-06-01 20:47 ` Paul Moore 2021-06-02 12:40 ` Daniel Borkmann 2021-06-02 12:40 ` Daniel Borkmann 2021-06-02 15:13 ` Paul Moore 2021-06-02 15:13 ` Paul Moore 2021-06-03 18:52 ` Daniel Borkmann 2021-06-03 18:52 ` Daniel Borkmann 2021-06-04 4:50 ` Paul Moore 2021-06-04 4:50 ` Paul Moore 2021-06-04 18:02 ` Daniel Borkmann 2021-06-04 18:02 ` Daniel Borkmann 2021-06-04 23:34 ` Paul Moore 2021-06-04 23:34 ` Paul Moore 2021-06-05 0:08 ` Alexei Starovoitov 2021-06-05 0:08 ` Alexei Starovoitov 2021-06-05 18:10 ` Casey Schaufler 2021-06-05 18:10 ` Casey Schaufler 2021-06-05 18:17 ` Linus Torvalds 2021-06-05 18:17 ` Linus Torvalds 2021-06-06 2:11 ` Paul Moore 2021-06-06 2:11 ` Paul Moore 2021-06-06 1:30 ` Paul Moore 2021-06-06 1:30 ` Paul Moore 2021-06-02 13:39 ` Ondrej Mosnacek 2021-06-02 13:39 ` Ondrej Mosnacek 2021-06-03 17:46 ` Paul Moore 2021-06-03 17:46 ` Paul Moore 2021-06-08 11:01 ` Ondrej Mosnacek 2021-06-08 11:01 ` Ondrej Mosnacek 2021-06-09 2:40 ` Paul Moore 2021-06-09 2:40 ` Paul Moore 2021-05-28 13:58 ` Steven Rostedt 2021-05-28 13:58 ` Steven Rostedt
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