On Tue, Aug 2, 2016 at 2:55 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Wed, Jul 27, 2016 at 07:46:23AM -0700, Jeff Vander Stoep wrote: >> +++ b/kernel/events/core.c >> @@ -355,7 +355,11 @@ static struct srcu_struct pmus_srcu; >> * 2 - disallow kernel profiling for unpriv >> * 3 - disallow all unpriv perf event use >> */ >> +#ifdef CONFIG_SECURITY_PERF_EVENTS_RESTRICT >> +int sysctl_perf_event_paranoid __read_mostly = 3; >> +#else >> int sysctl_perf_event_paranoid __read_mostly = 2; >> +#endif >> >> /* Minimum for 512 kiB + 1 user control page */ >> int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ >> diff --git a/security/Kconfig b/security/Kconfig >> index df28f2b..2a93551 100644 >> --- a/security/Kconfig >> +++ b/security/Kconfig >> @@ -18,6 +18,15 @@ config SECURITY_DMESG_RESTRICT >> >> If you are unsure how to answer this question, answer N. >> >> +config SECURITY_PERF_EVENTS_RESTRICT >> + bool "Restrict unprivileged use of performance events" >> + depends on PERF_EVENTS >> + help >> + If you say Y here, the kernel.perf_event_paranoid sysctl >> + will be set to 3 by default, and no unprivileged use of the >> + perf_event_open syscall will be permitted unless it is >> + changed. > > NAK. > > Apart from the fact that I hate the 3 thing this is not how you do > default CONFIG knobs for !bool state variables. > > Use an "int" config not a "bool" config and allow all options to be > default. How about leaving off 2/2 and just keeping 1/2 of this series? -Kees -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
