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From:   Dongliang Mu <dzm91@hust.edu.cn>
To:     Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc:     Dongliang Mu <mudongliangabcd@gmail.com>,
        syzkaller <syzkaller@googlegroups.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] HID: bigben: fix slab-out-of-bounds Write in bigben_probe
Date:   Fri,  6 May 2022 15:24:25 +0800
Message-Id: <20220506072425.1121900-1-dzm91@hust.edu.cn>
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From: Dongliang Mu <mudongliangabcd@gmail.com>

There is a slab-out-of-bounds Write bug in hid-bigbenff driver.
The problem is the driver assumes the device must have an input but
some malicious devices violate this assumption.

Fix this by checking hid_device's input is non-empty before its usage.

Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
v1->v2: modify return directly to goto error_hw_stop;
 drivers/hid/hid-bigbenff.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hid/hid-bigbenff.c b/drivers/hid/hid-bigbenff.c
index 74ad8bf98bfd..e8c5e3ac9fff 100644
--- a/drivers/hid/hid-bigbenff.c
+++ b/drivers/hid/hid-bigbenff.c
@@ -347,6 +347,12 @@ static int bigben_probe(struct hid_device *hid,
 	bigben->report = list_entry(report_list->next,
 		struct hid_report, list);
 
+	if (list_empty(&hid->inputs)) {
+		hid_err(hid, "no inputs found\n");
+		error = -ENODEV;
+		goto error_hw_stop;
+	}
+
 	hidinput = list_first_entry(&hid->inputs, struct hid_input, list);
 	set_bit(FF_RUMBLE, hidinput->input->ffbit);
 
-- 
2.25.1