cx231xx-audio: fix NULL-deref at probe

commit 65f921647f4c89a2068478c89691f39b309b58f7 upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer or accessing memory beyond the endpoint array should a
malicious device lack the expected endpoints.

Fixes: e0d3bafd0258 ("V4L/DVB (10954): Add cx231xx USB driver")
Cc: Sri Deevi <Srinivasa.Deevi@conexant.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/usb/cx231xx/cx231xx-audio.c b/drivers/media/usb/cx231xx/cx231xx-audio.c
index 9b925874d392de05a7c44e3192aa8953e68c5a27..b6b12250de6c28b14f9cd2a6c8b3ffb58d05dfac 100644 (file)
--- a/drivers/media/usb/cx231xx/cx231xx-audio.c
+++ b/drivers/media/usb/cx231xx/cx231xx-audio.c
@@ -702,6 +702,11 @@ static int cx231xx_audio_init(struct cx231xx *dev)
                                            hs_config_info[0].interface_info.
                                            audio_index + 1];
 
+       if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1) {
+               snd_card_free(card);
+               return -ENODEV;
+       }
+
        adev->end_point_addr =
            uif->altsetting[0].endpoint[isoc_pipe].desc.
                        bEndpointAddress;
@@ -717,8 +722,14 @@ static int cx231xx_audio_init(struct cx231xx *dev)
        }
 
        for (i = 0; i < adev->num_alt; i++) {
-               u16 tmp =
-                   le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.
+               u16 tmp;
+
+               if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1) {
+                       snd_card_free(card);
+                       return -ENODEV;
+               }
+
+               tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.
                                wMaxPacketSize);
                adev->alt_max_pkt_size[i] =
                    (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);