HID: pidff: Fix null pointer dereference in pidff_find_fields

[ Upstream commit 22a05462c3d0eee15154faf8d13c49e6295270a5 ]

This function triggered a null pointer dereference if used to search for
a report that isn't implemented on the device. This happened both for
optional and required reports alike.

The same logic was applied to pidff_find_special_field and although
pidff_init_fields should return an error earlier if one of the required
reports is missing, future modifications could change this logic and
resurface this possible null pointer dereference again.

LKML bug report:
https://lore.kernel.org/all/CAL-gK7f5=R0nrrQdPtaZZr1fd-cdAMbDMuZ_NLA8vM0SX+nGSw@mail.gmail.com

Reported-by: Nolan Nicholson <nolananicholson@gmail.com>
Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@gmail.com>
Reviewed-by: Michał Kopeć <michal@nozomi.space>
Reviewed-by: Paul Dino Jones <paul@spacefreak18.xyz>
Tested-by: Paul Dino Jones <paul@spacefreak18.xyz>
Tested-by: Cristóferson Bueno <cbueno81@gmail.com>
Tested-by: Pablo Cisneros <patchkez@protonmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hid/usbhid/hid-pidff.c b/drivers/hid/usbhid/hid-pidff.c
index ba0d7cb15377ea612142559a1cd4b6f32729bb80..d237736cb25a36805e94052bb5ce53b4935aa7a9 100644 (file)
--- a/drivers/hid/usbhid/hid-pidff.c
+++ b/drivers/hid/usbhid/hid-pidff.c
@@ -772,6 +772,11 @@ static int pidff_find_fields(struct pidff_usage *usage, const u8 *table,
 {
        int i, j, k, found;
 
+       if (!report) {
+               pr_debug("pidff_find_fields, null report\n");
+               return -1;
+       }
+
        for (k = 0; k < count; k++) {
                found = 0;
                for (i = 0; i < report->maxfield; i++) {
@@ -885,6 +890,11 @@ static struct hid_field *pidff_find_special_field(struct hid_report *report,
 {
        int i;
 
+       if (!report) {
+               pr_debug("pidff_find_special_field, null report\n");
+               return NULL;
+       }
+
        for (i = 0; i < report->maxfield; i++) {
                if (report->field[i]->logical == (HID_UP_PID | usage) &&
                    report->field[i]->report_count > 0) {