cx231xx-cards: fix NULL-deref at probe

commit 0cd273bb5e4d1828efaaa8dfd11b7928131ed149 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-cards.c b/drivers/media/usb/cx231xx/cx231xx-cards.c
index 791f00c6276b1e489e38f019d4e7bbe40362a0e2..9592ba876451afb293e8fc12dbe37f4184e400c7 100644 (file)
--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -1291,6 +1291,9 @@ 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;
 
@@ -1305,7 +1308,12 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
        }
 
        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);
                cx231xx_info("Alternate setting %i, max size= %i\n", i,
                             dev->video_mode.alt_max_pkt_size[i]);
@@ -1320,6 +1328,9 @@ 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;
@@ -1337,8 +1348,12 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
        }
 
        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);
@@ -1356,6 +1371,9 @@ 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;
@@ -1372,7 +1390,12 @@ static int cx231xx_init_v4l2(struct cx231xx *dev,
        }
 
        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);
@@ -1526,6 +1549,11 @@ 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;
@@ -1543,7 +1571,14 @@ 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] =