Date: Wed, 5 Jun 2013 14:30:13 +0200 From: Stephane Eranian <eranian@...gle.com> To: Peter Zijlstra <peterz@...radead.org> Cc: OSS Security List <oss-security@...ts.openwall.com>, "ak@...ux.intel.com" <ak@...ux.intel.com>, security@...nel.org, Marcus Meissner <meissner@...e.de> Subject: Re: CVE Request: More perf security fixes Hi, On Wed, Jun 5, 2013 at 2:15 PM, Peter Zijlstra <peterz@...radead.org> wrote: > On Wed, Jun 05, 2013 at 02:10:54PM +0200, Petr Matousek wrote: >> Hello, Peter. >> >> On Tue, Jun 04, 2013 at 05:53:16PM +0200, Marcus Meissner wrote: >> > 1. Info leak (?) via PERF_SAMPLE_BRANCH_KERNEL >> > >> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=7cc23cd6c0c7d7f4bee057607e7ce01568925717 >> > >> > commit 7cc23cd6c0c7d7f4bee057607e7ce01568925717 >> > Author: Peter Zijlstra <a.p.zijlstra@...llo.nl> >> > Date: Fri May 3 14:11:25 2013 +0200 >> > >> > perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL >> > >> > We should always have proper privileges when requesting kernel >> > data. >> > >> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl> >> > Cc: <stable@...nel.org> >> > Cc: Andi Kleen <ak@...ux.intel.com> >> > Cc: eranian@...gle.com >> > Link: http://email@example.com >> > [ Fix build error reported by fengguang.wu@...el.com, propagate error code back. ] >> > Signed-off-by: Ingo Molnar <mingo@...nel.org> >> > Link: http://firstname.lastname@example.org >> >> There is similar check in perf_copy_attr() which is called from >> perf_event_open syscall -- >> >> /* kernel level capture: check permissions */ >> if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) >> && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) >> return -EACCES; >> >> It seems to me that it covers PERF_SAMPLE_BRANCH_KERNEL as well. Am I >> missing something? >> > > I overlooked it, also its slightly broken. See the discussion at: > https://lkml.org/lkml/2013/5/21/166 > Yes, there was a typo in the constant. Was checking the wrong bits. Now it is fixed with the patch referred to by Peter. >
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