From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 17 Jan 2018 08:08:27 +0100 From: Christoph Hellwig To: Al Viro Cc: Jeff Moyer , Christoph Hellwig , Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 32/32] aio: implement io_pgetevents Message-ID: <20180117070827.GA26868@lst.de> References: <20180110155853.32348-1-hch@lst.de> <20180110155853.32348-33-hch@lst.de> <20180115085310.GB32532@lst.de> <20180116120433.GA14579@lst.de> <20180117042721.GT13338@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180117042721.GT13338@ZenIV.linux.org.uk> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jan 17, 2018 at 04:27:21AM +0000, Al Viro wrote: > On Tue, Jan 16, 2018 at 07:41:24PM -0500, Jeff Moyer wrote: > > if (sigmask) { > > - if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) > > + if (!access_ok(VERIFY_READ, sigmask, > > + sizeof(void *) + sizeof(size_t)) || > > + __get_user(up, (sigset_t __user * __user *)sigmask) || > > + __get_user(sigsetsize, > > + (size_t __user *)(sigmask + sizeof(void *)))) > > return -EFAULT; > > How about copy_from_user() on a struct? Making eyes bleed is fun, but > people tend to get annoyed when you do it to them... Above is the copy & paste version from pselect. I've got both copy_from_user and that horrible version in my tree, and if we really need this awfull calling convention copy_from_user certainly is much better. pselect also should be switched to explicit struct + copy_from_user while we're at it. In fact glibc defines a struct for the userland version to start with.