tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

USB: usb_parse_endpoint: ignore reserved bits

Browse Source 
Reading bEndpointAddress the spec tells is that:
  b7   is direction, which must be ignored
  b6:4 are reserved which are to be set to zero
  b3:0 are the endpoint address

In order to be backwards compatible with possible future versions of USB
we have to be ready with devices using those bits. That means that we
also have to ignore them like we do with the direction bit.

In consequence the only illegal address you can encoding in four bits is
endpoint zero, for which no descriptor must exist. Hence the check for
exceeding the upper limit on endpoint addresses is removed.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20240502115259.31076-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oliver Neukum
2024-05-02 13:51:40 +02:00
committed by Greg Kroah-Hartman
parent 080e73c941
commit b3e40fc857
1 changed files with 4 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/usb/core/config.c
+4 -4
View File
@@ -279,11 +279,11 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno,
goto skip_to_next_endpoint_or_interface_descriptor;
}
i = d->bEndpointAddress & ~USB_ENDPOINT_DIR_MASK;
if (i >= 16 || i == 0) {
i = d->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
if (i == 0) {
dev_notice(ddev, "config %d interface %d altsetting %d has an "
"invalid endpoint with address 0x%X, skipping\n",
cfgno, inum, asnum, d->bEndpointAddress);
"invalid descriptor for endpoint zero, skipping\n",
cfgno, inum, asnum);
goto skip_to_next_endpoint_or_interface_descriptor;
}