[PATCH AUTOSEL 4.14 4/8] Input: add bounds checking to input_set_capability()

Sasha Levin
2022-04-07T01:30:46Z

From: Jeff LaBundy <jeff@labundy.com>

[ Upstream commit 409353cbe9fe48f6bc196114c442b1cff05a39bc ]

Update input_set_capability() to prevent kernel panic in case the
event code exceeds the bitmap for the given event type.

Suggested-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220320032537.545250-1-jeff@labundy.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/input/input.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/drivers/input/input.c b/drivers/input/input.c
index cb8ff919ba82..a7c8c61a2612 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -50,6 +50,17 @@ static DEFINE_MUTEX(input_mutex);

static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };

+static const unsigned int input_max_code[EV_CNT] = {
+ [EV_KEY] = KEY_MAX,
+ [EV_REL] = REL_MAX,
+ [EV_ABS] = ABS_MAX,
+ [EV_MSC] = MSC_MAX,
+ [EV_SW] = SW_MAX,
+ [EV_LED] = LED_MAX,
+ [EV_SND] = SND_MAX,
+ [EV_FF] = FF_MAX,
+};
+
static inline int is_event_supported(unsigned int code,
unsigned long *bm, unsigned int max)
{
@@ -1915,6 +1926,14 @@ EXPORT_SYMBOL(input_free_device);
*/
void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
{
+ if (type < EV_CNT && input_max_code[type] &&
+ code > input_max_code[type]) {
+ pr_err("%s: invalid code %u for type %u\n", __func__, code,
+ type);
+ dump_stack();
+ return;
+ }
+
switch (type) {
case EV_KEY:
__set_bit(code, dev->keybit);
--
2.35.1