[PATCH 4.19 058/118] USB: check usb_get_extra_descriptor for proper size

Greg Kroah-Hartman
2018-12-11T16:04:16Z

From: Mathias Payer <mathias.payer@nebelwelt.net>

commit 704620afc70cf47abb9d6a1a57f3825d2bca49cf upstream.

When reading an extra descriptor, we need to properly check the minimum
and maximum size allowed, to prevent from invalid data being sent by a
device.

Reported-by: Hui Peng <benquike@gmail.com>
Reported-by: Mathias Payer <mathias.payer@nebelwelt.net>
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hui Peng <benquike@gmail.com>
Signed-off-by: Mathias Payer <mathias.payer@nebelwelt.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/core/hub.c | 2 +-
drivers/usb/core/usb.c | 6 +++---
drivers/usb/host/hwa-hc.c | 2 +-
include/linux/usb.h | 4 ++--
4 files changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2250,7 +2250,7 @@ static int usb_enumerate_device_otg(stru
/* descriptor may appear anywhere in config */
err = __usb_get_extra_descriptor(udev->rawdescriptors[0],
le16_to_cpu(udev->config[0].desc.wTotalLength),
- USB_DT_OTG, (void **) &desc);
+ USB_DT_OTG, (void **) &desc, sizeof(*desc));
if (err || !(desc->bmAttributes & USB_OTG_HNP))
return 0;

--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -832,14 +832,14 @@ EXPORT_SYMBOL_GPL(usb_get_current_frame_
*/

int __usb_get_extra_descriptor(char *buffer, unsigned size,
- unsigned char type, void **ptr)
+ unsigned char type, void **ptr, size_t minsize)
{
struct usb_descriptor_header *header;

while (size >= sizeof(struct usb_descriptor_header)) {
header = (struct usb_descriptor_header *)buffer;

- if (header->bLength < 2) {
+ if (header->bLength < 2 || header->bLength > size) {
printk(KERN_ERR
"%s: bogus descriptor, type %d length %d\n",
usbcore_name,
@@ -848,7 +848,7 @@ int __usb_get_extra_descriptor(char *buf
return -1;
}

- if (header->bDescriptorType == type) {
+ if (header->bDescriptorType == type && header->bLength >= minsize) {
*ptr = header;
return 0;
}
--- a/drivers/usb/host/hwa-hc.c
+++ b/drivers/usb/host/hwa-hc.c
@@ -640,7 +640,7 @@ static int hwahc_security_create(struct
top = itr + itr_size;
result = __usb_get_extra_descriptor(usb_dev->rawdescriptors[index],
le16_to_cpu(usb_dev->actconfig->desc.wTotalLength),
- USB_DT_SECURITY, (void **) &secd);
+ USB_DT_SECURITY, (void **) &secd, sizeof(*secd));
if (result == -1) {
dev_warn(dev, "BUG? WUSB host has no security descriptors\n");
return 0;
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -407,11 +407,11 @@ struct usb_host_bos {
};

int __usb_get_extra_descriptor(char *buffer, unsigned size,
- unsigned char type, void **ptr);
+ unsigned char type, void **ptr, size_t min);
#define usb_get_extra_descriptor(ifpoint, type, ptr) \
__usb_get_extra_descriptor((ifpoint)->extra, \
(ifpoint)->extralen, \
- type, (void **)ptr)
+ type, (void **)ptr, sizeof(**(ptr)))

/* ----------------------------------------------------------------------- */