setup.code can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability.
This issue was detected with the help of Smatch: drivers/input/misc/uinput.c:512 uinput_abs_setup() warn: potential spectre issue 'dev->absinfo' [w] (local cap) Fix this by sanitizing setup.code before using it to index dev->absinfo. 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 Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com> --- drivers/input/misc/uinput.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 8ec483e..97b0809 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -42,6 +42,8 @@ #include <linux/input/mt.h> #include "../input-compat.h" +#include <linux/nospec.h> + #define UINPUT_NAME "uinput" #define UINPUT_BUFFER_SIZE 16 #define UINPUT_NUM_REQUESTS 16 @@ -497,6 +499,7 @@ static int uinput_abs_setup(struct uinput_device *udev, if (setup.code > ABS_MAX) return -ERANGE; + setup.code = array_index_nospec(setup.code, ABS_MAX + 1); dev = udev->dev; -- 2.7.4
