As reported by Dan Carpenter, if the axes_enable field wasn't found,
trying to find the axes themselves will result in a null pointer
dereference. This could only occur with a broken PID descriptor, but
it's worth protecting from.
Exit early if the axes_enable wasn't found AND add a gate to the
pidff_find_special_keys to exit early if the passed HID field is null.
This will protect again null dereferencing in the future and properly
return 0 found special keys.
Fixes:
Commit 1d72e7bd340b ("HID: pidff: Add support for AXES_ENABLE field")
Made on top of for-6.18/pidff
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@xxxxxxxxx>
---
drivers/hid/usbhid/hid-pidff.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index 0342c0a3f476..edd61ef50e16 100644
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -1194,6 +1194,9 @@ static int pidff_find_special_keys(int *keys, struct hid_field *fld,
{
int found = 0;
+ if (!fld)
+ return 0;
+
for (int i = 0; i < count; i++) {
keys[i] = pidff_find_usage(fld, usage_page | usagetable[i]) + 1;
if (keys[i])
@@ -1299,11 +1302,13 @@ static int pidff_find_special_fields(struct pidff_device *pidff)
return -1;
}
- if (!pidff->axes_enable)
+ if (!pidff->axes_enable) {
hid_info(pidff->hid, "axes enable field not found!\n");
- else
- hid_dbg(pidff->hid, "axes enable report count: %u\n",
- pidff->axes_enable->report_count);
+ return 0;
+ }
+
+ hid_dbg(pidff->hid, "axes enable report count: %u\n",
+ pidff->axes_enable->report_count);
uint found = PIDFF_FIND_GENERAL_DESKTOP(direction_axis_id, axes_enable,
direction_axis);
@@ -1311,7 +1316,7 @@ static int pidff_find_special_fields(struct pidff_device *pidff)
pidff->axis_count = found;
hid_dbg(pidff->hid, "found direction axes: %u", found);
- for (int i = 0; i < sizeof(pidff_direction_axis); i++) {
+ for (int i = 0; i < ARRAY_SIZE(pidff_direction_axis); i++) {
if (!pidff->direction_axis_id[i])
continue;
--
2.50.1
