linux-kernel - Re: [PATCH v2 1/3] USB: serial: return errors from break handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 6 Jun 2023 13:13:30 +0200
From:   Oliver Neukum <oneukum@...e.com>
To:     Johan Hovold <johan@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Corey Minyard <minyard@....org>
Subject: Re: [PATCH v2 1/3] USB: serial: return errors from break handling

On 04.06.23 14:35, Johan Hovold wrote:
> @@ -1077,15 +1077,19 @@ static void pl2303_set_break(struct usb_serial_port *port, bool enable)
>   	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
>   				 BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
>   				 0, NULL, 0, 100);
> -	if (result)
> +	if (result) {
>   		dev_err(&port->dev, "error sending break = %d\n", result);
> +		return result;
> +	}
> +
> +	return 0;
>   }

Hi,

this code was always fishy, but I am afraid it worked by accident albeit
spamming the logs.
If I may quote from the kerneldoc of usb_control_msg():

  * usb_control_msg - Builds a control urb, sends it off and waits for completion

[..]

  * Return: If successful, the number of bytes transferred. Otherwise, a negative
  * error number.
  */

You need to test for < 0, not != 0

	Regards
		Oliver