[media] cx231xx-cards: fix NULL-deref at probe

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: stable <stable@vger.kernel.org>     # 2.6.30
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>

diff --git a/drivers/media/usb/cx231xx/cx231xx-cards.c b/drivers/media/usb/cx231xx/cx231xx-cards.c
index 9b28d57006af693c0619eedd25630b8e61b19d5e..a1007d0052900393c17ac5497c1600e6e46264e2 100644 (file)
--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -1425,6 +1425,9 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
 
        uif = udev->actconfig->interface[idx];
 
+       if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1)
+               return -ENODEV;
+
        dev->video_mode.end_point_addr = uif->altsetting[0].endpoint[isoc_pipe].desc.bEndpointAddress;
        dev->video_mode.num_alt = uif->num_altsetting;
 
@@ -1438,7 +1441,12 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
                return -ENOMEM;
 
        for (i = 0; i < dev->video_mode.num_alt; i++) {
-               u16 tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.wMaxPacketSize);
+               u16 tmp;
+
+               if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1)
+                       return -ENODEV;
+
+               tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].desc.wMaxPacketSize);
                dev->video_mode.alt_max_pkt_size[i] = (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);
                dev_dbg(dev->dev,
                        "Alternate setting %i, max size= %i\n", i,
@@ -1455,6 +1463,9 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
        }
        uif = udev->actconfig->interface[idx];
 
+       if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1)
+               return -ENODEV;
+
        dev->vbi_mode.end_point_addr =
            uif->altsetting[0].endpoint[isoc_pipe].desc.
                        bEndpointAddress;
@@ -1471,8 +1482,12 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
                return -ENOMEM;
 
        for (i = 0; i < dev->vbi_mode.num_alt; i++) {
-               u16 tmp =
-                   le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].
+               u16 tmp;
+
+               if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1)
+                       return -ENODEV;
+
+               tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].
                                desc.wMaxPacketSize);
                dev->vbi_mode.alt_max_pkt_size[i] =
                    (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);
@@ -1492,6 +1507,9 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
        }
        uif = udev->actconfig->interface[idx];
 
+       if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1)
+               return -ENODEV;
+
        dev->sliced_cc_mode.end_point_addr =
            uif->altsetting[0].endpoint[isoc_pipe].desc.
                        bEndpointAddress;
@@ -1506,7 +1524,12 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
                return -ENOMEM;
 
        for (i = 0; i < dev->sliced_cc_mode.num_alt; i++) {
-               u16 tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].
+               u16 tmp;
+
+               if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1)
+                       return -ENODEV;
+
+               tmp = le16_to_cpu(uif->altsetting[i].endpoint[isoc_pipe].
                                desc.wMaxPacketSize);
                dev->sliced_cc_mode.alt_max_pkt_size[i] =
                    (tmp & 0x07ff) * (((tmp & 0x1800) >> 11) + 1);
@@ -1675,6 +1698,11 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
                }
                uif = udev->actconfig->interface[idx];
 
+               if (uif->altsetting[0].desc.bNumEndpoints < isoc_pipe + 1) {
+                       retval = -ENODEV;
+                       goto err_video_alt;
+               }
+
                dev->ts1_mode.end_point_addr =
                    uif->altsetting[0].endpoint[isoc_pipe].
                                desc.bEndpointAddress;
@@ -1692,7 +1720,14 @@ static int cx231xx_usb_probe(struct usb_interface *interface,
                }
 
                for (i = 0; i < dev->ts1_mode.num_alt; i++) {
-                       u16 tmp = le16_to_cpu(uif->altsetting[i].
+                       u16 tmp;
+
+                       if (uif->altsetting[i].desc.bNumEndpoints < isoc_pipe + 1) {
+                               retval = -ENODEV;
+                               goto err_video_alt;
+                       }
+
+                       tmp = le16_to_cpu(uif->altsetting[i].
                                                endpoint[isoc_pipe].desc.
                                                wMaxPacketSize);
                        dev->ts1_mode.alt_max_pkt_size[i] =