4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Zijlstra <pet...@infradead.org>
commit ef9ee4ad38445a30909c48998624861716f2a994 upstream.
> arch/x86/events/core.c:319 set_ext_hw_attr() warn: potential spectre issue
> 'hw_cache_event_ids[cache_type]' (local cap)
> arch/x86/events/core.c:319 set_ext_hw_attr() warn: potential spectre issue
> 'hw_cache_event_ids' (local cap)
> arch/x86/events/core.c:328 set_ext_hw_attr() warn: potential spectre issue
> 'hw_cache_extra_regs[cache_type]' (local cap)
> arch/x86/events/core.c:328 set_ext_hw_attr() warn: potential spectre issue
> 'hw_cache_extra_regs' (local cap)
Userspace controls @config which contains 3 (byte) fields used for a 3
dimensional array deref.
Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: <sta...@kernel.org>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Stephane Eranian <eran...@google.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Vince Weaver <vincent.wea...@maine.edu>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/x86/events/core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -304,17 +304,20 @@ set_ext_hw_attr(struct hw_perf_event *hw
config = attr->config;
- cache_type = (config >> 0) & 0xff;
+ cache_type = (config >> 0) & 0xff;
if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
return -EINVAL;
+ cache_type = array_index_nospec(cache_type, PERF_COUNT_HW_CACHE_MAX);
cache_op = (config >> 8) & 0xff;
if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
return -EINVAL;
+ cache_op = array_index_nospec(cache_op, PERF_COUNT_HW_CACHE_OP_MAX);
cache_result = (config >> 16) & 0xff;
if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
return -EINVAL;
+ cache_result = array_index_nospec(cache_result,
PERF_COUNT_HW_CACHE_RESULT_MAX);
val = hw_cache_event_ids[cache_type][cache_op][cache_result];
