4.4-stable review patch. If anyone has any objections, please let me know.
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From: Chris Dickens christopher.a.dickens@gmail.com
[ Upstream commit 5d6ae4f0da8a64a185074dabb1b2f8c148efa741 ]
When handling an OS descriptor request, one of the first operations is to zero out the request buffer using the wLength from the setup packet. There is no bounds checking, so a wLength > 4096 would clobber memory adjacent to the request buffer. Fix this by taking the min of wLength and the request buffer length prior to the memset. While at it, define the buffer length in a header file so that magic numbers don't appear throughout the code.
When returning data to the host, the data length should be the min of the wLength and the valid data we have to return. Currently we are returning wLength, thus requests for a wLength greater than the amount of data in the OS descriptor buffer would return invalid (albeit zero'd) data following the valid descriptor data. Fix this by counting the number of bytes when constructing the data and using this when determining the length of the request.
Signed-off-by: Chris Dickens christopher.a.dickens@gmail.com Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/composite.c | 40 +++++++++++++++++++--------------------- include/linux/usb/composite.h | 3 +++ 2 files changed, 22 insertions(+), 21 deletions(-)
--- a/drivers/usb/gadget/composite.c +++ b/drivers/usb/gadget/composite.c @@ -1328,7 +1328,7 @@ static int count_ext_compat(struct usb_c return res; }
-static void fill_ext_compat(struct usb_configuration *c, u8 *buf) +static int fill_ext_compat(struct usb_configuration *c, u8 *buf) { int i, count;
@@ -1355,10 +1355,12 @@ static void fill_ext_compat(struct usb_c buf += 23; } count += 24; - if (count >= 4096) - return; + if (count + 24 >= USB_COMP_EP0_OS_DESC_BUFSIZ) + return count; } } + + return count; }
static int count_ext_prop(struct usb_configuration *c, int interface) @@ -1403,25 +1405,20 @@ static int fill_ext_prop(struct usb_conf struct usb_os_desc *d; struct usb_os_desc_ext_prop *ext_prop; int j, count, n, ret; - u8 *start = buf;
f = c->interface[interface]; + count = 10; /* header length */ for (j = 0; j < f->os_desc_n; ++j) { if (interface != f->os_desc_table[j].if_id) continue; d = f->os_desc_table[j].os_desc; if (d) list_for_each_entry(ext_prop, &d->ext_prop, entry) { - /* 4kB minus header length */ - n = buf - start; - if (n >= 4086) - return 0; - - count = ext_prop->data_len + + n = ext_prop->data_len + ext_prop->name_len + 14; - if (count > 4086 - n) - return -EINVAL; - usb_ext_prop_put_size(buf, count); + if (count + n >= USB_COMP_EP0_OS_DESC_BUFSIZ) + return count; + usb_ext_prop_put_size(buf, n); usb_ext_prop_put_type(buf, ext_prop->type); ret = usb_ext_prop_put_name(buf, ext_prop->name, ext_prop->name_len); @@ -1447,11 +1444,12 @@ static int fill_ext_prop(struct usb_conf default: return -EINVAL; } - buf += count; + buf += n; + count += n; } }
- return 0; + return count; }
/* @@ -1720,6 +1718,7 @@ unknown: req->complete = composite_setup_complete; buf = req->buf; os_desc_cfg = cdev->os_desc_config; + w_length = min_t(u16, w_length, USB_COMP_EP0_OS_DESC_BUFSIZ); memset(buf, 0, w_length); buf[5] = 0x01; switch (ctrl->bRequestType & USB_RECIP_MASK) { @@ -1743,8 +1742,8 @@ unknown: count += 16; /* header */ put_unaligned_le32(count, buf); buf += 16; - fill_ext_compat(os_desc_cfg, buf); - value = w_length; + value = fill_ext_compat(os_desc_cfg, buf); + value = min_t(u16, w_length, value); } break; case USB_RECIP_INTERFACE: @@ -1773,8 +1772,7 @@ unknown: interface, buf); if (value < 0) return value; - - value = w_length; + value = min_t(u16, w_length, value); } break; } @@ -2038,8 +2036,8 @@ int composite_os_desc_req_prepare(struct goto end; }
- /* OS feature descriptor length <= 4kB */ - cdev->os_desc_req->buf = kmalloc(4096, GFP_KERNEL); + cdev->os_desc_req->buf = kmalloc(USB_COMP_EP0_OS_DESC_BUFSIZ, + GFP_KERNEL); if (!cdev->os_desc_req->buf) { ret = PTR_ERR(cdev->os_desc_req->buf); kfree(cdev->os_desc_req); --- a/include/linux/usb/composite.h +++ b/include/linux/usb/composite.h @@ -53,6 +53,9 @@ /* big enough to hold our biggest descriptor */ #define USB_COMP_EP0_BUFSIZ 1024
+/* OS feature descriptor length <= 4kB */ +#define USB_COMP_EP0_OS_DESC_BUFSIZ 4096 + #define USB_MS_TO_HS_INTERVAL(x) (ilog2((x * 1000 / 125)) + 1) struct usb_configuration;