USB: core: Add type-specific length check of BOS descriptors

As most of BOS descriptors are longer in length than their header
'struct usb_dev_cap_header', comparing solely with it is not sufficient
to avoid out-of-bounds access to BOS descriptors.

This patch adds descriptor type specific length check in
usb_get_bos_descriptor() to fix the issue.

Signed-off-by: Masakazu Mokuno <masakazu.mokuno@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index da8acd9..55b198b 100644 (file)
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -905,14 +905,25 @@ void usb_release_bos_descriptor(struct usb_device *dev)
        }
 }
 
+static const __u8 bos_desc_len[256] = {
+       [USB_CAP_TYPE_WIRELESS_USB] = USB_DT_USB_WIRELESS_CAP_SIZE,
+       [USB_CAP_TYPE_EXT]          = USB_DT_USB_EXT_CAP_SIZE,
+       [USB_SS_CAP_TYPE]           = USB_DT_USB_SS_CAP_SIZE,
+       [USB_SSP_CAP_TYPE]          = USB_DT_USB_SSP_CAP_SIZE(1),
+       [CONTAINER_ID_TYPE]         = USB_DT_USB_SS_CONTN_ID_SIZE,
+       [USB_PTM_CAP_TYPE]          = USB_DT_USB_PTM_ID_SIZE,
+};
+
 /* Get BOS descriptor set */
 int usb_get_bos_descriptor(struct usb_device *dev)
 {
        struct device *ddev = &dev->dev;
        struct usb_bos_descriptor *bos;
        struct usb_dev_cap_header *cap;
+       struct usb_ssp_cap_descriptor *ssp_cap;
        unsigned char *buffer;
-       int length, total_len, num, i;
+       int length, total_len, num, i, ssac;
+       __u8 cap_type;
        int ret;
 
        bos = kzalloc(sizeof(struct usb_bos_descriptor), GFP_KERNEL);
@@ -965,7 +976,13 @@ int usb_get_bos_descriptor(struct usb_device *dev)
                        dev->bos->desc->bNumDeviceCaps = i;
                        break;
                }
+               cap_type = cap->bDevCapabilityType;
                length = cap->bLength;
+               if (bos_desc_len[cap_type] && length < bos_desc_len[cap_type]) {
+                       dev->bos->desc->bNumDeviceCaps = i;
+                       break;
+               }
+
                total_len -= length;
 
                if (cap->bDescriptorType != USB_DT_DEVICE_CAPABILITY) {
@@ -973,7 +990,7 @@ int usb_get_bos_descriptor(struct usb_device *dev)
                        continue;
                }
 
-               switch (cap->bDevCapabilityType) {
+               switch (cap_type) {
                case USB_CAP_TYPE_WIRELESS_USB:
                        /* Wireless USB cap descriptor is handled by wusb */
                        break;
@@ -986,8 +1003,11 @@ int usb_get_bos_descriptor(struct usb_device *dev)
                                (struct usb_ss_cap_descriptor *)buffer;
                        break;
                case USB_SSP_CAP_TYPE:
-                       dev->bos->ssp_cap =
-                               (struct usb_ssp_cap_descriptor *)buffer;
+                       ssp_cap = (struct usb_ssp_cap_descriptor *)buffer;
+                       ssac = (le32_to_cpu(ssp_cap->bmAttributes) &
+                               USB_SSP_SUBLINK_SPEED_ATTRIBS) + 1;
+                       if (length >= USB_DT_USB_SSP_CAP_SIZE(ssac))
+                               dev->bos->ssp_cap = ssp_cap;
                        break;
                case CONTAINER_ID_TYPE:
                        dev->bos->ss_id =

diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
index 41a0a81..c4c79aa 100644 (file)
--- a/include/uapi/linux/usb/ch9.h
+++ b/include/uapi/linux/usb/ch9.h
@@ -880,6 +880,8 @@ struct usb_wireless_cap_descriptor {        /* Ultra Wide Band */
        __u8  bReserved;
 } __attribute__((packed));
 
+#define USB_DT_USB_WIRELESS_CAP_SIZE   11
+
 /* USB 2.0 Extension descriptor */
 #define        USB_CAP_TYPE_EXT                2
 
@@ -1072,6 +1074,7 @@ struct usb_ptm_cap_descriptor {
        __u8  bDevCapabilityType;
 } __attribute__((packed));
 
+#define USB_DT_USB_PTM_ID_SIZE         3
 /*
  * The size of the descriptor for the Sublink Speed Attribute Count
  * (SSAC) specified in bmAttributes[4:0].