[PATCH net] net: usb: pegasus: validate USB endpoints

[PATCH net] net: usb: pegasus: validate USB endpoints

[Greg Kroah-Hartman]

The pegasus driver should validate that the device it is probing has the
proper number and types of USB endpoints it is expecting before it binds
to it.  If a malicious device were to not have the same urbs the driver
will crash later on when it blindly accesses these endpoints.

Cc: Petko Manolov <petkan@nucleusys.com>
Cc: stable <stable@kernel.org>
Assisted-by: gkh_clanker_2000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/usb/pegasus.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index 4f539b5d509a..94c17fed0bd4 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -801,8 +801,19 @@ static void unlink_all_urbs(pegasus_t *pegasus)
 
 static int alloc_urbs(pegasus_t *pegasus)
 {
+	static const u8 bulk_ep_addr[] = {
+		1 | USB_DIR_IN,
+		2 | USB_DIR_OUT,
+		0};
+	static const u8 int_ep_addr[] = {
+		3 | USB_DIR_IN,
+		0};
 	int res = -ENOMEM;
 
+	if (!usb_check_bulk_endpoints(pegasus->intf, bulk_ep_addr) ||
+	    !usb_check_int_endpoints(pegasus->intf, int_ep_addr))
+		return -ENODEV;
+
 	pegasus->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
 	if (!pegasus->rx_urb) {
 		return res;
@@ -1143,6 +1154,7 @@ static int pegasus_probe(struct usb_interface *intf,
 
 	pegasus = netdev_priv(net);
 	pegasus->dev_index = dev_index;
+	pegasus->intf = intf;
 
 	res = alloc_urbs(pegasus);
 	if (res < 0) {
@@ -1154,7 +1166,6 @@ static int pegasus_probe(struct usb_interface *intf,
 
 	INIT_DELAYED_WORK(&pegasus->carrier_check, check_carrier);
 
-	pegasus->intf = intf;
 	pegasus->usb = dev;
 	pegasus->net = net;
 
-- 
2.53.0

Re: [PATCH net] net: usb: pegasus: validate USB endpoints

[Alan Stern]

On Mon, Feb 23, 2026 at 01:58:48PM +0100, Greg Kroah-Hartman wrote:
> The pegasus driver should validate that the device it is probing has the
> proper number and types of USB endpoints it is expecting before it binds
> to it.  If a malicious device were to not have the same urbs the driver
> will crash later on when it blindly accesses these endpoints.
> 
> Cc: Petko Manolov <petkan@nucleusys.com>
> Cc: stable <stable@kernel.org>
> Assisted-by: gkh_clanker_2000
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---

This does much the same thing as

https://lore.kernel.org/linux-usb/20260222050633.410165-1-n7l8m4@u.northwestern.edu/T/#u

and that patch also removes some magic numbers.

BTW, what is gkh_clanker_2000?

Alan Stern

>  drivers/net/usb/pegasus.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
> index 4f539b5d509a..94c17fed0bd4 100644
> --- a/drivers/net/usb/pegasus.c
> +++ b/drivers/net/usb/pegasus.c
> @@ -801,8 +801,19 @@ static void unlink_all_urbs(pegasus_t *pegasus)
>  
>  static int alloc_urbs(pegasus_t *pegasus)
>  {
> +	static const u8 bulk_ep_addr[] = {
> +		1 | USB_DIR_IN,
> +		2 | USB_DIR_OUT,
> +		0};
> +	static const u8 int_ep_addr[] = {
> +		3 | USB_DIR_IN,
> +		0};
>  	int res = -ENOMEM;
>  
> +	if (!usb_check_bulk_endpoints(pegasus->intf, bulk_ep_addr) ||
> +	    !usb_check_int_endpoints(pegasus->intf, int_ep_addr))
> +		return -ENODEV;
> +
>  	pegasus->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
>  	if (!pegasus->rx_urb) {
>  		return res;
> @@ -1143,6 +1154,7 @@ static int pegasus_probe(struct usb_interface *intf,
>  
>  	pegasus = netdev_priv(net);
>  	pegasus->dev_index = dev_index;
> +	pegasus->intf = intf;
>  
>  	res = alloc_urbs(pegasus);
>  	if (res < 0) {
> @@ -1154,7 +1166,6 @@ static int pegasus_probe(struct usb_interface *intf,
>  
>  	INIT_DELAYED_WORK(&pegasus->carrier_check, check_carrier);
>  
> -	pegasus->intf = intf;
>  	pegasus->usb = dev;
>  	pegasus->net = net;
>  
> -- 
> 2.53.0
> 
> 

Re: [PATCH net] net: usb: pegasus: validate USB endpoints

[Greg Kroah-Hartman]

On Mon, Feb 23, 2026 at 09:39:52AM -0500, Alan Stern wrote:
> On Mon, Feb 23, 2026 at 01:58:48PM +0100, Greg Kroah-Hartman wrote:
> > The pegasus driver should validate that the device it is probing has the
> > proper number and types of USB endpoints it is expecting before it binds
> > to it.  If a malicious device were to not have the same urbs the driver
> > will crash later on when it blindly accesses these endpoints.
> > 
> > Cc: Petko Manolov <petkan@nucleusys.com>
> > Cc: stable <stable@kernel.org>
> > Assisted-by: gkh_clanker_2000
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> 
> This does much the same thing as
> 
> https://lore.kernel.org/linux-usb/20260222050633.410165-1-n7l8m4@u.northwestern.edu/T/#u
> 
> and that patch also removes some magic numbers.

Yes it does, that's a much nicer patch than mine.

> BTW, what is gkh_clanker_2000?

A hacked up system of tools/scripts I'm running here to find stuff like
"take this previously applied commit that fixed a problem, does the same
pattern need to be also done anywhere else in the tree"?  It finds a lot
of stuff and then I sift through it and see if anything is actually real
or not and if so, make up a patch for it.  It was my "merge window is
giving me a respite from reviewing patches" hobby project this past
week.

Now if I was really good, I could turn the output into a coccinelle
script, as this is just simple patterns.

Also it seems that we aren't running the coccinelle scripts anymore, as
many things it has found are already covered by that, I wonder why that
is...

thanks,

greg k-h

Re: [PATCH net] net: usb: pegasus: validate USB endpoints

[Alan Stern]

On Mon, Feb 23, 2026 at 03:54:30PM +0100, Greg Kroah-Hartman wrote:
> On Mon, Feb 23, 2026 at 09:39:52AM -0500, Alan Stern wrote:
> > BTW, what is gkh_clanker_2000?
> 
> A hacked up system of tools/scripts I'm running here to find stuff like
> "take this previously applied commit that fixed a problem, does the same
> pattern need to be also done anywhere else in the tree"?  It finds a lot
> of stuff and then I sift through it and see if anything is actually real
> or not and if so, make up a patch for it.  It was my "merge window is
> giving me a respite from reviewing patches" hobby project this past
> week.
> 
> Now if I was really good, I could turn the output into a coccinelle
> script, as this is just simple patterns.

It's a little surprising that nobody has asked an AI to do this sort of 
thing yet (as far as I know).  It's hard to say whether the results 
would be better than you get with your hacked-up system of 
tools/scripts, but it might be.

Alan Stern

Re: [PATCH net] net: usb: pegasus: validate USB endpoints

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 23 Feb 2026 13:58:48 +0100 you wrote:
> The pegasus driver should validate that the device it is probing has the
> proper number and types of USB endpoints it is expecting before it binds
> to it.  If a malicious device were to not have the same urbs the driver
> will crash later on when it blindly accesses these endpoints.
> 
> Cc: Petko Manolov <petkan@nucleusys.com>
> Cc: stable <stable@kernel.org>
> Assisted-by: gkh_clanker_2000
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> [...]

Here is the summary with links:
  - [net] net: usb: pegasus: validate USB endpoints
    https://git.kernel.org/netdev/net/c/11de1d3ae556

You are awesome, thank you!
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