[PATCH] hid: bigben_probe(): validate report count

[PATCH] hid: bigben_probe(): validate report count

[Pietro Borrello]

bigben_probe() does not validate that the output report has the
needed report values in the first field.
A malicious device registering a report with one field and a single
value causes an head OOB write in bigben_worker() when
accessing report_field->value[1] to report_field->value[7].
Use hid_validate_values() which takes care of all the needed checks.

Fixes: 256a90ed9e46 ("HID: hid-bigbenff: driver for BigBen Interactive PS3OFMINIPAD gamepad")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
---
 drivers/hid/hid-bigbenff.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/hid-bigbenff.c b/drivers/hid/hid-bigbenff.c
index e8b16665860d..1d0033a008ac 100644
--- a/drivers/hid/hid-bigbenff.c
+++ b/drivers/hid/hid-bigbenff.c
@@ -318,7 +318,6 @@ static int bigben_probe(struct hid_device *hid,
 {
 	struct bigben_device *bigben;
 	struct hid_input *hidinput;
-	struct list_head *report_list;
 	struct led_classdev *led;
 	char *name;
 	size_t name_sz;
@@ -343,14 +342,12 @@ static int bigben_probe(struct hid_device *hid,
 		return error;
 	}
 
-	report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
-	if (list_empty(report_list)) {
+	bigben->report = hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 8);
+	if (!bigben->report) {
 		hid_err(hid, "no output report found\n");
 		error = -ENODEV;
 		goto error_hw_stop;
 	}
-	bigben->report = list_entry(report_list->next,
-		struct hid_report, list);
 
 	if (list_empty(&hid->inputs)) {
 		hid_err(hid, "no inputs found\n");

---
base-commit: 4ec5183ec48656cec489c49f989c508b68b518e3
change-id: 20230211-bigben-oob-8dd66a3c3cb3

Best regards,
-- 
Pietro Borrello <borrello@diag.uniroma1.it>

Re: [PATCH] hid: bigben_probe(): validate report count

[Benjamin Tissoires]

On Sun, 12 Feb 2023 00:01:44 +0000, Pietro Borrello wrote:
> bigben_probe() does not validate that the output report has the
> needed report values in the first field.
> A malicious device registering a report with one field and a single
> value causes an head OOB write in bigben_worker() when
> accessing report_field->value[1] to report_field->value[7].
> Use hid_validate_values() which takes care of all the needed checks.
> 
> [...]

Applied, thanks!

[1/1] hid: bigben_probe(): validate report count
      commit: b94335f899542a0da5fafc38af8edcaf90195843

Best regards,
-- 
Benjamin Tissoires <benjamin.tissoires@redhat.com>