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From:   Phong Tran <tranmanphong@gmail.com>
To:     pebolle@tiscali.nl, isdn@linux-pingi.de, gregkh@linuxfoundation.org
Cc:     gigaset307x-common@lists.sourceforge.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        linux-kernel-mentees@lists.linuxfoundation.org,
        Phong Tran <tranmanphong@gmail.com>,
        syzbot+35b1c403a14f5c89eba7@syzkaller.appspotmail.com
Subject: [PATCH] isdn/gigaset: check endpoint null in gigaset_probe
Date:   Fri, 26 Jul 2019 20:35:28 +0700
Message-Id: <20190726133528.11063-1-tranmanphong@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org
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This fixed the potential reference NULL pointer while using variable
endpoint.

Reported-by: syzbot+35b1c403a14f5c89eba7@syzkaller.appspotmail.com
Tested by syzbot:
https://groups.google.com/d/msg/syzkaller-bugs/wnHG8eRNWEA/Qn2HhjNdBgAJ

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
---
 drivers/isdn/gigaset/usb-gigaset.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/isdn/gigaset/usb-gigaset.c b/drivers/isdn/gigaset/usb-gigaset.c
index 1b9b43659bdf..2e011f3db59e 100644
--- a/drivers/isdn/gigaset/usb-gigaset.c
+++ b/drivers/isdn/gigaset/usb-gigaset.c
@@ -703,6 +703,10 @@ static int gigaset_probe(struct usb_interface *interface,
 	usb_set_intfdata(interface, cs);
 
 	endpoint = &hostif->endpoint[0].desc;
+        if (!endpoint) {
+		dev_err(cs->dev, "Couldn't get control endpoint\n");
+		return -ENODEV;
+	}
 
 	buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
 	ucs->bulk_out_size = buffer_size;
@@ -722,6 +726,11 @@ static int gigaset_probe(struct usb_interface *interface,
 	}
 
 	endpoint = &hostif->endpoint[1].desc;
+        if (!endpoint) {
+		dev_err(cs->dev, "Endpoint not available\n");
+		retval = -ENODEV;
+		goto error;
+	}
 
 	ucs->busy = 0;
 
-- 
2.20.1