From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B451C433E0 for ; Wed, 24 Jun 2020 18:37:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08CFE207E8 for ; Wed, 24 Jun 2020 18:37:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406117AbgFXShq (ORCPT ); Wed, 24 Jun 2020 14:37:46 -0400 Received: from verein.lst.de ([213.95.11.211]:45586 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405914AbgFXShq (ORCPT ); Wed, 24 Jun 2020 14:37:46 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 7A3C168B02; Wed, 24 Jun 2020 20:37:43 +0200 (CEST) Date: Wed, 24 Jun 2020 20:37:43 +0200 From: Christoph Hellwig To: Matthew Wilcox Cc: Linus Torvalds , Christoph Hellwig , Al Viro , Luis Chamberlain , Kees Cook , Iurii Zaikin , Linux Kernel Mailing List , linux-fsdevel Subject: Re: [PATCH 03/11] fs: add new read_uptr and write_uptr file operations Message-ID: <20200624183743.GA26747@lst.de> References: <20200624162901.1814136-1-hch@lst.de> <20200624162901.1814136-4-hch@lst.de> <20200624175644.GR21350@casper.infradead.org> <20200624175905.GA25981@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200624175905.GA25981@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Jun 24, 2020 at 07:59:05PM +0200, Christoph Hellwig wrote: > On Wed, Jun 24, 2020 at 06:56:44PM +0100, Matthew Wilcox wrote: > > /* don't even try if the size is too large */ > > + error = -ENOMEM; > > if (count > KMALLOC_MAX_SIZE) > > - return -ENOMEM; > > + goto out; > > + kbuf = kzalloc(count, GFP_KERNEL); > > + if (!kbuf) > > + goto out; > > > > if (write) { > > + error = -EFAULT; > > + if (!copy_from_iter_full(kbuf, count, iter)) > > goto out; > > } > > The nul-termination for the write cases seems to be lost here. Version with the count and termination fixed below. Can I get your signoff? If testing passes that means I can go back to my kernel_read/write version from the set_fs removal tree with it. diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 42c5128c7d1c76..36ac7b0e4ba80d 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -540,12 +541,13 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, return err; } -static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf, - size_t count, loff_t *ppos, int write) +static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, + int write) { - struct inode *inode = file_inode(filp); + struct inode *inode = file_inode(iocb->ki_filp); struct ctl_table_header *head = grab_header(inode); struct ctl_table *table = PROC_I(inode)->sysctl_entry; + size_t count = iov_iter_count(iter); void *kbuf; ssize_t error; @@ -566,35 +568,33 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf, goto out; /* don't even try if the size is too large */ - if (count > KMALLOC_MAX_SIZE) - return -ENOMEM; + error = -ENOMEM; + if (count + !!write > KMALLOC_MAX_SIZE) + goto out; + kbuf = kzalloc(count, GFP_KERNEL); + if (!kbuf) + goto out; if (write) { - kbuf = memdup_user_nul(ubuf, count); - if (IS_ERR(kbuf)) { - error = PTR_ERR(kbuf); - goto out; - } - } else { - error = -ENOMEM; - kbuf = kzalloc(count, GFP_KERNEL); - if (!kbuf) + error = -EFAULT; + if (!copy_from_iter_full(kbuf, count, iter)) goto out; + ((char *)kbuf)[count] = '\0'; } error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, - ppos); + &iocb->ki_pos); if (error) goto out_free_buf; /* careful: calling conventions are nasty here */ - error = table->proc_handler(table, write, kbuf, &count, ppos); + error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); if (error) goto out_free_buf; if (!write) { error = -EFAULT; - if (copy_to_user(ubuf, kbuf, count)) + if (copy_to_iter(kbuf, count, iter) < count) goto out_free_buf; } @@ -607,16 +607,14 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf, return error; } -static ssize_t proc_sys_read(struct file *filp, char __user *buf, - size_t count, loff_t *ppos) +static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) { - return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); + return proc_sys_call_handler(iocb, iter, 0); } -static ssize_t proc_sys_write(struct file *filp, const char __user *buf, - size_t count, loff_t *ppos) +static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) { - return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); + return proc_sys_call_handler(iocb, iter, 1); } static int proc_sys_open(struct inode *inode, struct file *filp) @@ -853,8 +851,8 @@ static int proc_sys_getattr(const struct path *path, struct kstat *stat, static const struct file_operations proc_sys_file_operations = { .open = proc_sys_open, .poll = proc_sys_poll, - .read = proc_sys_read, - .write = proc_sys_write, + .read_iter = proc_sys_read, + .write_iter = proc_sys_write, .llseek = default_llseek, }; -- 2.26.2