From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] drivers/char/mem.c: Add /dev/ioports, supporting 16-bit and 32-bit ports Date: Fri, 09 May 2014 21:58:43 +0200 Message-ID: <9233735.5FfZoZovqP@wuerfel> References: <20140509191914.GA7286@jtriplet-mobl1> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20140509191914.GA7286@jtriplet-mobl1> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Josh Triplett Cc: Greg Kroah-Hartman , akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Friday 09 May 2014 12:19:16 Josh Triplett wrote: > + if (!access_ok(VERIFY_WRITE, buf, count)) > + return -EFAULT; > + if (port > 65535) > + return 0; This should probably test against IO_SPACE_LIMIT, which may be zero, something larger than 65536 or even ULONG_MAX, depending on the architecture. In cases where this IO_SPACE_LIMIT is zero or ULONG_MAX, we should probably disallow access completely. The former case is for architectures that don't have any I/O ports, the other is either a mistake, or is used when inb is defined as readb, and the port numbers are just virtual addresses. Arnd