[PATCH 3/6] [media] cx231xx-cards: fix NULL-deref at probe

Johan Hovold
2017-03-13T12:55:28Z

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>
---
drivers/media/usb/cx231xx/cx231xx-cards.c | 45 +++++++++++++++++++++++++++----
1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/drivers/media/usb/cx231xx/cx231xx-cards.c b/drivers/media/usb/cx231xx/cx231xx-cards.c
index f730fdbc9156..f850267a0095 100644
--- a/drivers/media/usb/cx231xx/cx231xx-cards.c
+++ b/drivers/media/usb/cx231xx/cx231xx-cards.c
@@ -1426,6 +1426,9 @@ 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;

@@ -1439,7 +1442,12 @@ 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,
@@ -1456,6 +1464,9 @@ 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;
@@ -1472,8 +1483,12 @@ 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);
@@ -1493,6 +1508,9 @@ 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;
@@ -1507,7 +1525,12 @@ 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);
@@ -1676,6 +1699,11 @@ 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;
@@ -1693,7 +1721,14 @@ 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] =
--
2.12.0