From: Oliver Neukum <oneukum@suse.com>
To: linux-usb@vger.kernel.org, gregKH@linuxfoundation.org,
stern@rowland.harvard.edu
Cc: Oliver Neukum <oneukum@suse.com>
Subject: [PATCHv3] usb: usb_parse_endpoint ignore reserved bits
Date: Thu, 2 May 2024 13:51:40 +0200 [thread overview]
Message-ID: <20240502115259.31076-1-oneukum@suse.com> (raw)
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>
---
v2: Improved commit log
v3: Symbolic mask and improved error message
drivers/usb/core/config.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 7f8d33f92ddb..3362af165ef5 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -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;
}
--
2.44.0
next reply other threads:[~2024-05-02 11:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-02 11:51 Oliver Neukum [this message]
2024-05-02 14:00 ` [PATCHv3] usb: usb_parse_endpoint ignore reserved bits Alan Stern
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