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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Hans de Goede" <hdegoede@redhat.com>,
        "Johan Hovold" <johan@kernel.org>,
        "Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
        "Hans Verkuil" <hverkuil-cisco@xs4all.nl>
Date:   Fri, 24 Apr 2020 00:07:34 +0100
Message-ID: <lsq.1587683028.991461894@decadent.org.uk>
Subject: [PATCH 3.16 227/245] media: ov519: add missing endpoint sanity checks
In-Reply-To: <lsq.1587683027.831233700@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit 998912346c0da53a6dbb71fab3a138586b596b30 upstream.

Make sure to check that we have at least one endpoint before accessing
the endpoint array to avoid dereferencing a NULL-pointer on stream
start.

Note that these sanity checks are not redundant as the driver is mixing
looking up altsettings by index and by number, which need not coincide.

Fixes: 1876bb923c98 ("V4L/DVB (12079): gspca_ov519: add support for the ov511 bridge")
Fixes: b282d87332f5 ("V4L/DVB (12080): gspca_ov519: Fix ov518+ with OV7620AE (Trust spacecam 320)")
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/media/usb/gspca/ov519.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/media/usb/gspca/ov519.c
+++ b/drivers/media/usb/gspca/ov519.c
@@ -3497,6 +3497,11 @@ static void ov511_mode_init_regs(struct
 		return;
 	}
 
+	if (alt->desc.bNumEndpoints < 1) {
+		sd->gspca_dev.usb_err = -ENODEV;
+		return;
+	}
+
 	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
 	reg_w(sd, R51x_FIFO_PSIZE, packet_size >> 5);
 
@@ -3622,6 +3627,11 @@ static void ov518_mode_init_regs(struct
 		return;
 	}
 
+	if (alt->desc.bNumEndpoints < 1) {
+		sd->gspca_dev.usb_err = -ENODEV;
+		return;
+	}
+
 	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
 	ov518_reg_w32(sd, R51x_FIFO_PSIZE, packet_size & ~7, 2);