4.4-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra peterz@infradead.org
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/kernel/cpu/perf_event_intel_cstate.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/cpu/perf_event_intel_cstate.c +++ b/arch/x86/kernel/cpu/perf_event_intel_cstate.c @@ -88,6 +88,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/perf_event.h> +#include <linux/nospec.h> #include <asm/cpu_device_id.h> #include "perf_event.h"
@@ -409,6 +410,7 @@ static int cstate_pmu_event_init(struct } 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;