[PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[Andy Guo (郭卫斌)]

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From: guoweibin <guoweibin@inspur.com>

when the rxstate function executes the 'goto buffer_aint_mapped' code
branch, it will always copy the fifocnt bytes data to request->buf,
which may cause request->buf out of bounds. for Ethernet-over-USB will
cause skb_over_panic when a packet larger than mtu is recived.

Fix it by add the length check :
fifocnt = min_t(unsigned, request->length - request->actual, fifocnt);

Signed-off-by: guoweibin <guoweibin@inspur.com>
---
 v2:
-fix format error
 drivers/usb/musb/musb_gadget.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 51274b87f46c..4ad5a1f31d7e 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -760,6 +760,7 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 			musb_writew(epio, MUSB_RXCSR, csr);
 
 buffer_aint_mapped:
+			fifo_count = min_t(unsigned, request->length - request->actual, fifo_count);
 			musb_read_fifo(musb_ep->hw_ep, fifo_count, (u8 *)
 					(request->buf + request->actual));
 			request->actual += fifo_count;

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Re: [PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[gregkh]

On Wed, Jul 27, 2022 at 08:43:34AM +0000, Andy Guo (郭卫斌) wrote:
> From: guoweibin <guoweibin@inspur.com>

Your From: in your email has your real name, why not use that instead of
just putting your email alias here?

> 
> when the rxstate function executes the 'goto buffer_aint_mapped' code
> branch, it will always copy the fifocnt bytes data to request->buf,
> which may cause request->buf out of bounds. for Ethernet-over-USB will
> cause skb_over_panic when a packet larger than mtu is recived.

How can we get a bigger packet than mtu?

> 
> Fix it by add the length check :
> fifocnt = min_t(unsigned, request->length - request->actual, fifocnt);
> 
> Signed-off-by: guoweibin <guoweibin@inspur.com>

Same here.

> ---
>  v2:
> -fix format error
>  drivers/usb/musb/musb_gadget.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
> index 51274b87f46c..4ad5a1f31d7e 100644
> --- a/drivers/usb/musb/musb_gadget.c
> +++ b/drivers/usb/musb/musb_gadget.c
> @@ -760,6 +760,7 @@ static void rxstate(struct musb *musb, struct musb_request *req)
>  			musb_writew(epio, MUSB_RXCSR, csr);
>  
>  buffer_aint_mapped:
> +			fifo_count = min_t(unsigned, request->length - request->actual, fifo_count);

Why the case to "unsigned"?

And if we get a too big packet, shouldn't we drop it?

And what does this have to do with a usb-ethernet device, this is in the
generic musb code, not an ethernet driver.

thanks,

greg k-h

答复: [vger.kernel.org代发]Re: [PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[Andy Guo (郭卫斌)]

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Re: 答复: [vger.kernel.org代发]Re: [PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[gregkh]

On Thu, Jul 28, 2022 at 01:14:17AM +0000, Andy Guo (郭卫斌) wrote:

As can be seen in the archives:
	https://lore.kernel.org/all/2c234d13d7274763b0102b83ce65b8ff@inspur.com/
this message could not be decoded, sorry.

Please resend in plain text format.

thanks,

greg k-h

RE: 答复: [vger.kernel.org代发]Re: [PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

[Andy Guo (郭卫斌)]

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I'm sorroy,
I use Enterprise mailbox doesn't work very well.
I will send this patch through another mailbox.

Thanks

guoweibin

-----Original Message-----
From: gregkh@linuxfoundation.org <gregkh@linuxfoundation.org> 
Sent: Thursday, July 28, 2022 2:57 PM
To: Andy Guo (郭卫斌) <guoweibin@inspur.com>
Cc: b-liu@ti.com; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: 答复: [vger.kernel.org代发]Re: [PATCH v2] usb: musb: Fix musb_gadget.c rxstate may cause request->buf overflow problems

On Thu, Jul 28, 2022 at 01:14:17AM +0000, Andy Guo (郭卫斌) wrote:

As can be seen in the archives:
	https://lore.kernel.org/all/2c234d13d7274763b0102b83ce65b8ff@inspur.com/
this message could not be decoded, sorry.

Please resend in plain text format.

thanks,

greg k-h


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