This patch modifies the usb_authorize_device() function such as that it does
not reload the device descriptor for wired devices. The reasons for this
are as follows:
* Some devices dislike the master requesting the descriptor from them twice,
failing on the usb_get_device_descriptor() call with -ETIMEOUT. Observed this
on my Pretec 16GB flash drive (4146:ba65).
* Malicious device could send two different descriptors - one before
authorization, used by userspace to determine whether to authorize it and
second to be actually used by the kernel when determining which drivers to
bind.
Signed-off-by: Josef Gajdusek <atx@xxxxxxxx>
---
drivers/usb/core/hub.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 11e80ac..c096a1a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2543,11 +2543,14 @@ int usb_authorize_device(struct usb_device *usb_dev)
"can't autoresume for authorization: %d\n", result);
goto error_autoresume;
}
- result = usb_get_device_descriptor(usb_dev, sizeof(usb_dev->descriptor));
- if (result < 0) {
- dev_err(&usb_dev->dev, "can't re-read device descriptor for "
- "authorization: %d\n", result);
- goto error_device_descriptor;
+
+ if (usb_dev->wusb) {
+ result = usb_get_device_descriptor(usb_dev, sizeof(usb_dev->descriptor));
+ if (result < 0) {
+ dev_err(&usb_dev->dev, "can't re-read device descriptor for "
+ "authorization: %d\n", result);
+ goto error_device_descriptor;
+ }
}
usb_dev->authorized = 1;
--
2.0.4
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