USB: check serial-number string after device reset
This patch (as1048) extends the descriptor checking after a device is reset. Now the SerialNumber string descriptor is compared to its old value, in addition to the device and configuration descriptors. As a consequence, the kmalloc() call in usb_string() is now on the error-handling pathway for usb-storage. Hence its allocation type is changed to GFO_NOIO. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -136,10 +136,10 @@ aren't guaranteed to be 100% accurate.
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If you replace one USB device with another of the same type (same
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manufacturer, same IDs, and so on) there's an excellent chance the
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kernel won't detect the change. Serial numbers and other strings are
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not compared. In many cases it wouldn't help if they were, because
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manufacturers frequently omit serial numbers entirely in their
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devices.
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kernel won't detect the change. The serial number string and other
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descriptors are compared with the kernel's stored values, but this
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might not help since manufacturers frequently omit serial numbers
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entirely in their devices.
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Furthermore it's quite possible to leave a USB device exactly the same
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while changing its media. If you replace the flash memory card in a
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@ -3010,16 +3010,36 @@ void usb_hub_cleanup(void)
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usb_deregister(&hub_driver);
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} /* usb_hub_cleanup() */
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static int config_descriptors_changed(struct usb_device *udev)
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static int descriptors_changed(struct usb_device *udev,
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struct usb_device_descriptor *old_device_descriptor)
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{
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int changed = 0;
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unsigned index;
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unsigned len = 0;
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struct usb_config_descriptor *buf;
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unsigned serial_len = 0;
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unsigned len;
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unsigned old_length;
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int length;
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char *buf;
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if (memcmp(&udev->descriptor, old_device_descriptor,
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sizeof(*old_device_descriptor)) != 0)
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return 1;
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/* Since the idVendor, idProduct, and bcdDevice values in the
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* device descriptor haven't changed, we will assume the
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* Manufacturer and Product strings haven't changed either.
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* But the SerialNumber string could be different (e.g., a
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* different flash card of the same brand).
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*/
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if (udev->serial)
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serial_len = strlen(udev->serial) + 1;
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len = serial_len;
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for (index = 0; index < udev->descriptor.bNumConfigurations; index++) {
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if (len < le16_to_cpu(udev->config[index].desc.wTotalLength))
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len = le16_to_cpu(udev->config[index].desc.wTotalLength);
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old_length = le16_to_cpu(udev->config[index].desc.wTotalLength);
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len = max(len, old_length);
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}
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buf = kmalloc(len, GFP_NOIO);
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if (buf == NULL) {
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dev_err(&udev->dev, "no mem to re-read configs after reset\n");
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@ -3027,25 +3047,41 @@ static int config_descriptors_changed(struct usb_device *udev)
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return 1;
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}
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for (index = 0; index < udev->descriptor.bNumConfigurations; index++) {
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int length;
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int old_length = le16_to_cpu(udev->config[index].desc.wTotalLength);
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old_length = le16_to_cpu(udev->config[index].desc.wTotalLength);
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length = usb_get_descriptor(udev, USB_DT_CONFIG, index, buf,
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old_length);
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if (length < old_length) {
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if (length != old_length) {
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dev_dbg(&udev->dev, "config index %d, error %d\n",
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index, length);
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changed = 1;
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break;
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}
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if (memcmp (buf, udev->rawdescriptors[index], old_length)
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!= 0) {
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dev_dbg(&udev->dev, "config index %d changed (#%d)\n",
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index, buf->bConfigurationValue);
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index,
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((struct usb_config_descriptor *) buf)->
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bConfigurationValue);
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changed = 1;
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break;
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}
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}
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if (!changed && serial_len) {
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length = usb_string(udev, udev->descriptor.iSerialNumber,
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buf, serial_len);
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if (length + 1 != serial_len) {
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dev_dbg(&udev->dev, "serial string error %d\n",
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length);
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changed = 1;
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} else if (memcmp(buf, udev->serial, length) != 0) {
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dev_dbg(&udev->dev, "serial string changed\n");
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changed = 1;
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}
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}
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kfree(buf);
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return index != udev->descriptor.bNumConfigurations;
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return changed;
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}
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/**
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@ -3118,8 +3154,7 @@ int usb_reset_device(struct usb_device *udev)
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goto re_enumerate;
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/* Device might have changed firmware (DFU or similar) */
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if (memcmp(&udev->descriptor, &descriptor, sizeof descriptor)
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|| config_descriptors_changed (udev)) {
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if (descriptors_changed(udev, &descriptor)) {
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dev_info(&udev->dev, "device firmware changed\n");
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udev->descriptor = descriptor; /* for disconnect() calls */
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goto re_enumerate;
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@ -784,7 +784,7 @@ int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
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if (size <= 0 || !buf || !index)
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return -EINVAL;
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buf[0] = 0;
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tbuf = kmalloc(256, GFP_KERNEL);
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tbuf = kmalloc(256, GFP_NOIO);
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if (!tbuf)
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return -ENOMEM;
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