From b4ac6fbe5b1a3cb83d84cb9f7ab8df71d104f535 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Fri, 3 Jan 2020 17:35:10 +0100 Subject: [PATCH] media: stv06xx: add missing descriptor sanity checks commit 485b06aadb933190f4bc44e006076bc27a23f205 upstream. Make sure to check that we have two alternate settings and at least one endpoint before accessing the second altsetting structure and dereferencing the endpoint arrays. This specifically avoids dereferencing NULL-pointers or corrupting memory when a device does not have the expected descriptors. Note that the sanity checks in stv06xx_start() and pb0100_start() are not redundant as the driver is mixing looking up altsettings by index and by number, which may not coincide. Fixes: 8668d504d72c ("V4L/DVB (12082): gspca_stv06xx: Add support for st6422 bridge and sensor") Fixes: c0b33bdc5b8d ("[media] gspca-stv06xx: support bandwidth changing") Cc: stable # 2.6.31 Cc: Hans de Goede Signed-off-by: Johan Hovold Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/gspca/stv06xx/stv06xx.c | 19 ++++++++++++++++++- .../media/usb/gspca/stv06xx/stv06xx_pb0100.c | 4 ++++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/gspca/stv06xx/stv06xx.c b/drivers/media/usb/gspca/stv06xx/stv06xx.c index e72c3e1ab9ff..9caa5ef9d9e0 100644 --- a/drivers/media/usb/gspca/stv06xx/stv06xx.c +++ b/drivers/media/usb/gspca/stv06xx/stv06xx.c @@ -289,6 +289,9 @@ static int stv06xx_start(struct gspca_dev *gspca_dev) return -EIO; } + if (alt->desc.bNumEndpoints < 1) + return -ENODEV; + packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize); err = stv06xx_write_bridge(sd, STV_ISO_SIZE_L, packet_size); if (err < 0) @@ -313,11 +316,21 @@ out: static int stv06xx_isoc_init(struct gspca_dev *gspca_dev) { + struct usb_interface_cache *intfc; struct usb_host_interface *alt; struct sd *sd = (struct sd *) gspca_dev; + intfc = gspca_dev->dev->actconfig->intf_cache[0]; + + if (intfc->num_altsetting < 2) + return -ENODEV; + + alt = &intfc->altsetting[1]; + + if (alt->desc.bNumEndpoints < 1) + return -ENODEV; + /* Start isoc bandwidth "negotiation" at max isoc bandwidth */ - alt = &gspca_dev->dev->actconfig->intf_cache[0]->altsetting[1]; alt->endpoint[0].desc.wMaxPacketSize = cpu_to_le16(sd->sensor->max_packet_size[gspca_dev->curr_mode]); @@ -330,6 +343,10 @@ static int stv06xx_isoc_nego(struct gspca_dev *gspca_dev) struct usb_host_interface *alt; struct sd *sd = (struct sd *) gspca_dev; + /* + * Existence of altsetting and endpoint was verified in + * stv06xx_isoc_init() + */ alt = &gspca_dev->dev->actconfig->intf_cache[0]->altsetting[1]; packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize); min_packet_size = sd->sensor->min_packet_size[gspca_dev->curr_mode]; diff --git a/drivers/media/usb/gspca/stv06xx/stv06xx_pb0100.c b/drivers/media/usb/gspca/stv06xx/stv06xx_pb0100.c index e1ce96e9405f..8d855b2756ba 100644 --- a/drivers/media/usb/gspca/stv06xx/stv06xx_pb0100.c +++ b/drivers/media/usb/gspca/stv06xx/stv06xx_pb0100.c @@ -194,6 +194,10 @@ static int pb0100_start(struct sd *sd) alt = usb_altnum_to_altsetting(intf, sd->gspca_dev.alt); if (!alt) return -ENODEV; + + if (alt->desc.bNumEndpoints < 1) + return -ENODEV; + packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize); /* If we don't have enough bandwidth use a lower framerate */