4.9-stable review patch. If anyone has any objections, please let me know.
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From: Masakazu Mokuno masakazu.mokuno@gmail.com
commit 81cf4a45360f70528f1f64ba018d61cb5767249a upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/core/config.c | 28 ++++++++++++++++++++++++---- include/uapi/linux/usb/ch9.h | 3 +++ 2 files changed, 27 insertions(+), 4 deletions(-)
--- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -900,14 +900,25 @@ void usb_release_bos_descriptor(struct u } }
+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); @@ -960,7 +971,13 @@ int usb_get_bos_descriptor(struct usb_de 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) { @@ -968,7 +985,7 @@ int usb_get_bos_descriptor(struct usb_de continue; }
- switch (cap->bDevCapabilityType) { + switch (cap_type) { case USB_CAP_TYPE_WIRELESS_USB: /* Wireless USB cap descriptor is handled by wusb */ break; @@ -981,8 +998,11 @@ int usb_get_bos_descriptor(struct usb_de (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 = --- a/include/uapi/linux/usb/ch9.h +++ b/include/uapi/linux/usb/ch9.h @@ -854,6 +854,8 @@ struct usb_wireless_cap_descriptor { /* __u8 bReserved; } __attribute__((packed));
+#define USB_DT_USB_WIRELESS_CAP_SIZE 11 + /* USB 2.0 Extension descriptor */ #define USB_CAP_TYPE_EXT 2
@@ -1046,6 +1048,7 @@ 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].