From 4e4bb64df800c0c896231cad030f5a0ff0206e92 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra <peterz@infradead.org> Date: Fri, 20 Apr 2018 14:25:48 +0200 Subject: [PATCH] perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr commit a5f81290ce475489fa2551c01a07470c1a4c932e upstream. > arch/x86/events/intel/cstate.c:307 cstate_pmu_event_init() warn: potential spectre issue 'pkg_msr' (local cap) Userspace controls @attr, sanitize cfg (attr->config) before using it to index an array. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/events/intel/cstate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c index 72db0664a53d..357e82dc0e2a 100644 --- a/arch/x86/events/intel/cstate.c +++ b/arch/x86/events/intel/cstate.c @@ -91,6 +91,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/perf_event.h> +#include <linux/nospec.h> #include <asm/cpu_device_id.h> #include <asm/intel-family.h> #include "../perf_event.h" @@ -301,6 +302,7 @@ static int cstate_pmu_event_init(struct perf_event *event) } else if (event->pmu == &cstate_pkg_pmu) { if (cfg >= PERF_CSTATE_PKG_EVENT_MAX) return -EINVAL; + cfg = array_index_nospec((unsigned long)cfg, PERF_CSTATE_PKG_EVENT_MAX); if (!pkg_msr[cfg].attr) return -EINVAL; event->hw.event_base = pkg_msr[cfg].msr; -- 2.20.1