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([2401:4900:bc2b:c75c:ceb4:d41d:8705:b6d1]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-31586402e53sm35852556eec.11.2026.08.06.01.00.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Aug 2026 01:00:27 -0700 (PDT) From: Deepanshu Kartikey To: dmitry.torokhov@gmail.com Cc: kees@kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Deepanshu Kartikey , syzbot+683f6c071b5abfc266c1@syzkaller.appspotmail.com Subject: [PATCH] Input: sur40 - fix use-after-free in sur40_open() Date: Thu, 6 Aug 2026 13:30:18 +0530 Message-Id: <20260806080018.10050-1-kartikey406@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If any of the registration steps after input_register_device() fail (v4l2_device_register(), vb2_queue_init(), ctrl handler setup, video_register_device()), the error path frees sur40 via input_free_device() + kfree() without ever calling input_unregister_device(). Since the input device was already registered, it remains live and openable, so a racing open() (e.g. from udevd) can dereference the freed sur40 via sur40_open(). Split the unwind so that once input_register_device() has succeeded, the failure path properly calls input_unregister_device() before freeing sur40 and its buffer. Fixes: 08b936012964 ("Input: sur40 - switch to using polled mode of input d= evices") Reported-by: syzbot+683f6c071b5abfc266c1@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3D683f6c071b5abfc266c1 Tested-by: syzbot+683f6c071b5abfc266c1@syzkaller.appspotmail.com Signed-off-by: Deepanshu Kartikey --- drivers/input/touchscreen/sur40.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/= sur40.c index fe63d53d56db..b0958422ff76 100644 --- a/drivers/input/touchscreen/sur40.c +++ b/drivers/input/touchscreen/sur40.c @@ -808,6 +808,10 @@ static int sur40_probe(struct usb_interface *interface, video_unregister_device(&sur40->vdev); err_unreg_v4l2: v4l2_device_unregister(&sur40->v4l2); + input_unregister_device(input); + kfree(sur40->bulk_in_buffer); + kfree(sur40); + return error; err_free_buffer: kfree(sur40->bulk_in_buffer); err_free_input: --=20 2.34.1