* [PATCH] USB: core: Check buffer length matches wLength for control transfers
@ 2021-05-26 15:32 Alan Stern
2021-05-27 8:23 ` Johan Hovold
2021-05-27 11:46 ` Greg KH
0 siblings, 2 replies; 3+ messages in thread
From: Alan Stern @ 2021-05-26 15:32 UTC (permalink / raw)
To: Greg KH; +Cc: Johan Hovold, USB mailing list
A type of inconsistency that can show up in control URBs is when the
setup packet's wLength value does not match the URB's
transfer_buffer_length field. The two should always be equal;
differences could lead to information leaks or undefined behavior for
OUT transfers or overruns for IN transfers.
This patch adds a test for such mismatches during URB submission. If
the test fails, the submission is rejected with a -EBADR error code
(which is not used elsewhere in the USB core), and a debugging message
is logged for people interested in tracking down these errors.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Johan Hovold <johan@kernel.org>
---
[as1961]
Documentation/driver-api/usb/error-codes.rst | 3 +++
drivers/usb/core/urb.c | 6 ++++++
2 files changed, 9 insertions(+)
Index: usb-devel/drivers/usb/core/urb.c
===================================================================
--- usb-devel.orig/drivers/usb/core/urb.c
+++ usb-devel/drivers/usb/core/urb.c
@@ -410,6 +410,12 @@ int usb_submit_urb(struct urb *urb, gfp_
dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out),
"BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
urb->pipe, setup->bRequestType);
+ if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) {
+ dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n",
+ le16_to_cpu(setup->wLength),
+ urb->transfer_buffer_length);
+ return -EBADR;
+ }
} else {
is_out = usb_endpoint_dir_out(&ep->desc);
}
Index: usb-devel/Documentation/driver-api/usb/error-codes.rst
===================================================================
--- usb-devel.orig/Documentation/driver-api/usb/error-codes.rst
+++ usb-devel/Documentation/driver-api/usb/error-codes.rst
@@ -61,6 +61,9 @@ USB-specific:
(c) requested data transfer length is invalid: negative
or too large for the host controller.
+``-EBADR`` The wLength value in a control URB's setup packet does
+ not match the URB's transfer_buffer_length.
+
``-ENOSPC`` This request would overcommit the usb bandwidth reserved
for periodic transfers (interrupt, isochronous).
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] USB: core: Check buffer length matches wLength for control transfers
2021-05-26 15:32 [PATCH] USB: core: Check buffer length matches wLength for control transfers Alan Stern
@ 2021-05-27 8:23 ` Johan Hovold
2021-05-27 11:46 ` Greg KH
1 sibling, 0 replies; 3+ messages in thread
From: Johan Hovold @ 2021-05-27 8:23 UTC (permalink / raw)
To: Alan Stern; +Cc: Greg KH, USB mailing list
On Wed, May 26, 2021 at 11:32:44AM -0400, Alan Stern wrote:
> A type of inconsistency that can show up in control URBs is when the
> setup packet's wLength value does not match the URB's
> transfer_buffer_length field. The two should always be equal;
> differences could lead to information leaks or undefined behavior for
> OUT transfers or overruns for IN transfers.
>
> This patch adds a test for such mismatches during URB submission. If
> the test fails, the submission is rejected with a -EBADR error code
> (which is not used elsewhere in the USB core), and a debugging message
> is logged for people interested in tracking down these errors.
>
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> CC: Johan Hovold <johan@kernel.org>
Looks good.
Reviewed-by: Johan Hovold <johan@kernel.org>
> ---
>
>
> [as1961]
>
>
> Documentation/driver-api/usb/error-codes.rst | 3 +++
> drivers/usb/core/urb.c | 6 ++++++
> 2 files changed, 9 insertions(+)
>
> Index: usb-devel/drivers/usb/core/urb.c
> ===================================================================
> --- usb-devel.orig/drivers/usb/core/urb.c
> +++ usb-devel/drivers/usb/core/urb.c
> @@ -410,6 +410,12 @@ int usb_submit_urb(struct urb *urb, gfp_
> dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out),
> "BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
> urb->pipe, setup->bRequestType);
> + if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) {
> + dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n",
> + le16_to_cpu(setup->wLength),
> + urb->transfer_buffer_length);
> + return -EBADR;
> + }
> } else {
> is_out = usb_endpoint_dir_out(&ep->desc);
> }
> Index: usb-devel/Documentation/driver-api/usb/error-codes.rst
> ===================================================================
> --- usb-devel.orig/Documentation/driver-api/usb/error-codes.rst
> +++ usb-devel/Documentation/driver-api/usb/error-codes.rst
> @@ -61,6 +61,9 @@ USB-specific:
> (c) requested data transfer length is invalid: negative
> or too large for the host controller.
>
> +``-EBADR`` The wLength value in a control URB's setup packet does
> + not match the URB's transfer_buffer_length.
> +
> ``-ENOSPC`` This request would overcommit the usb bandwidth reserved
> for periodic transfers (interrupt, isochronous).
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] USB: core: Check buffer length matches wLength for control transfers
2021-05-26 15:32 [PATCH] USB: core: Check buffer length matches wLength for control transfers Alan Stern
2021-05-27 8:23 ` Johan Hovold
@ 2021-05-27 11:46 ` Greg KH
1 sibling, 0 replies; 3+ messages in thread
From: Greg KH @ 2021-05-27 11:46 UTC (permalink / raw)
To: Alan Stern; +Cc: Johan Hovold, USB mailing list
On Wed, May 26, 2021 at 11:32:44AM -0400, Alan Stern wrote:
> A type of inconsistency that can show up in control URBs is when the
> setup packet's wLength value does not match the URB's
> transfer_buffer_length field. The two should always be equal;
> differences could lead to information leaks or undefined behavior for
> OUT transfers or overruns for IN transfers.
>
> This patch adds a test for such mismatches during URB submission. If
> the test fails, the submission is rejected with a -EBADR error code
> (which is not used elsewhere in the USB core), and a debugging message
> is logged for people interested in tracking down these errors.
>
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
> CC: Johan Hovold <johan@kernel.org>
>
> ---
>
>
> [as1961]
>
>
> Documentation/driver-api/usb/error-codes.rst | 3 +++
> drivers/usb/core/urb.c | 6 ++++++
> 2 files changed, 9 insertions(+)
>
> Index: usb-devel/drivers/usb/core/urb.c
> ===================================================================
> --- usb-devel.orig/drivers/usb/core/urb.c
> +++ usb-devel/drivers/usb/core/urb.c
> @@ -410,6 +410,12 @@ int usb_submit_urb(struct urb *urb, gfp_
> dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out),
> "BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
> urb->pipe, setup->bRequestType);
> + if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) {
> + dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n",
> + le16_to_cpu(setup->wLength),
> + urb->transfer_buffer_length);
> + return -EBADR;
> + }
Looks good, let's see if this catches anything :)
now queued up, thanks.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-05-27 11:47 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-05-26 15:32 [PATCH] USB: core: Check buffer length matches wLength for control transfers Alan Stern
2021-05-27 8:23 ` Johan Hovold
2021-05-27 11:46 ` Greg KH
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