[PATCH 4.19 45/56] HID: steam: Prevent NULL pointer dereference in steam_{recv,send}_report

Greg Kroah-Hartman
2022-09-02T12:36:17Z

From: Lee Jones <lee.jones@linaro.org>

commit cd11d1a6114bd4bc6450ae59f6e110ec47362126 upstream.

It is possible for a malicious device to forgo submitting a Feature
Report. The HID Steam driver presently makes no prevision for this
and de-references the 'struct hid_report' pointer obtained from the
HID devices without first checking its validity. Let's change that.

Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
Fixes: c164d6abf3841 ("HID: add driver for Valve Steam Controller")
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hid/hid-steam.c | 10 ++++++++++
1 file changed, 10 insertions(+)

--- a/drivers/hid/hid-steam.c
+++ b/drivers/hid/hid-steam.c
@@ -134,6 +134,11 @@ static int steam_recv_report(struct stea
int ret;

r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
+ if (!r) {
+ hid_err(steam->hdev, "No HID_FEATURE_REPORT submitted - nothing to read\n");
+ return -EINVAL;
+ }
+
if (hid_report_len(r) < 64)
return -EINVAL;

@@ -165,6 +170,11 @@ static int steam_send_report(struct stea
int ret;

r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
+ if (!r) {
+ hid_err(steam->hdev, "No HID_FEATURE_REPORT submitted - nothing to read\n");
+ return -EINVAL;
+ }
+
if (hid_report_len(r) < 64)
return -EINVAL;