code->index can be controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.
Smatch warning: drivers/media/platform/exynos4-is/mipi-csis.c:549 s5pcsis_enum_mbus_code() warn: potential spectre issue 's5pcsis_formats' Fix this by sanitizing code->index before using it to index s5pcsis_formats. Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: sta...@vger.kernel.org Reported-by: Dan Carpenter <dan.carpen...@oracle.com> Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com> --- drivers/media/platform/exynos4-is/mipi-csis.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/media/platform/exynos4-is/mipi-csis.c b/drivers/media/platform/exynos4-is/mipi-csis.c index cba46a6..60104c1 100644 --- a/drivers/media/platform/exynos4-is/mipi-csis.c +++ b/drivers/media/platform/exynos4-is/mipi-csis.c @@ -35,6 +35,8 @@ #include "mipi-csis.h" +#include <linux/nospec.h> + static int debug; module_param(debug, int, 0644); MODULE_PARM_DESC(debug, "Debug level (0-2)"); @@ -545,7 +547,8 @@ static int s5pcsis_enum_mbus_code(struct v4l2_subdev *sd, { if (code->index >= ARRAY_SIZE(s5pcsis_formats)) return -EINVAL; - + code->index = array_index_nospec(code->index, + ARRAY_SIZE(s5pcsis_formats)); code->code = s5pcsis_formats[code->index].code; return 0; } -- 2.7.4
