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From:   Soumya Negi <soumya.negi97@gmail.com>
To:     Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc:     Soumya Negi <soumya.negi97@gmail.com>, linux-input@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] Input: Check sanity of pipe in pegasus_probe()
Date:   Tue,  4 Apr 2023 00:41:45 -0700
Message-Id: <20230404074145.11523-1-soumya.negi97@gmail.com>
Precedence: bulk

Fix WARNING in pegasus_open/usb_submit_urb
Syzbot bug: https://syzkaller.appspot.com/bug?id=bbc107584dcf3262253ce93183e51f3612aaeb13

Warning raised because pegasus_driver submits transfer request for
bogus URB(pipe type does not match endpoint type). Add sanity check at
probe time for pipe value extracted from endpoint descriptor. Probe
will fail if sanity check fails.

Reported-and-tested-by: syzbot+04ee0cb4caccaed12d78@syzkaller.appspotmail.com
Signed-off-by: Soumya Negi <soumya.negi97@gmail.com>
---
 drivers/input/tablet/pegasus_notetaker.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
index d836d3dcc6a2..a68da2988f9c 100644
--- a/drivers/input/tablet/pegasus_notetaker.c
+++ b/drivers/input/tablet/pegasus_notetaker.c
@@ -296,6 +296,12 @@ static int pegasus_probe(struct usb_interface *intf,
 	pegasus->intf = intf;
 
 	pipe = usb_rcvintpipe(dev, endpoint->bEndpointAddress);
+	/* Sanity check that pipe's type matches endpoint's type */
+	if (usb_pipe_type_check(dev, pipe)) {
+		error = -EINVAL;
+		goto err_free_mem;
+	}
+
 	pegasus->data_len = usb_maxpacket(dev, pipe);
 
 	pegasus->data = usb_alloc_coherent(dev, pegasus->data_len, GFP_KERNEL,
-- 
2.17.1