Date: Tue, 2 Aug 2016 11:52:43 +0200 From: Peter Zijlstra <peterz@...radead.org> To: Jeff Vander Stoep <jeffv@...gle.com> Cc: kernel-hardening@...ts.openwall.com, mingo@...hat.com, acme@...nel.org, alexander.shishkin@...ux.intel.com, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH 1/2] security, perf: allow further restriction of perf_event_open On Wed, Jul 27, 2016 at 07:45:46AM -0700, Jeff Vander Stoep wrote: > When kernel.perf_event_paranoid is set to 3 (or greater), disallow > all access to performance events by users without CAP_SYS_ADMIN. > > This new level of restriction is intended to reduce the attack > surface of the kernel. Perf is a valuable tool for developers but > is generally unnecessary and unused on production systems. Perf may > open up an attack vector to vulnerable device-specific drivers as > recently demonstrated in CVE-2016-0805, CVE-2016-0819, > CVE-2016-0843, CVE-2016-3768, and CVE-2016-3843. We have bugs we fix them, we don't kill complete infrastructure because of them. > This new level of > restriction allows for a safe default to be set on production systems > while leaving a simple means for developers to grant access . So the problem I have with this is that it will completely inhibit development of things like JITs that self-profile to re-compile frequently used code. I would much rather have an LSM hook where the security stuff can do more fine grained control of things. Allowing some apps perf usage while denying others.
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