From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH V36 27/29] tracefs: Restrict tracefs when the kernel is locked down Date: Wed, 24 Jul 2019 22:23:54 -0400 Message-ID: <20190724222354.7cbd6c6e@oasis.local.home> References: <20190718194415.108476-1-matthewgarrett@google.com> <20190718194415.108476-28-matthewgarrett@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190718194415.108476-28-matthewgarrett@google.com> Sender: linux-kernel-owner@vger.kernel.org To: Matthew Garrett Cc: jmorris@namei.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Matthew Garrett List-Id: linux-api@vger.kernel.org On Thu, 18 Jul 2019 12:44:13 -0700 Matthew Garrett wrote: > @@ -387,6 +412,7 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode, > struct dentry *parent, void *data, > const struct file_operations *fops) > { > + struct file_operations *proxy_fops; > struct dentry *dentry; > struct inode *inode; > > @@ -402,8 +428,18 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode, > if (unlikely(!inode)) > return failed_creating(dentry); > > + proxy_fops = kzalloc(sizeof(struct file_operations), GFP_KERNEL); > + if (!proxy_fops) I believe we need "iput(inode);" here. Or move the allocation before the inode allocation and free it on inode failure. -- Steve > + return failed_creating(dentry); > + > + if (!fops) > + fops = &tracefs_file_operations; > + > + dentry->d_fsdata = (void *)fops; > + memcpy(proxy_fops, fops, sizeof(*proxy_fops)); > + proxy_fops->open = default_open_file; > inode->i_mode = mode; > - inode->i_fop = fops ? fops : &tracefs_file_operations; > + inode->i_fop = proxy_fops; > inode->i_private = data; > d_instantiate(dentry, inode); > fsnotify_create(dentry->d_parent->d_inode, dentry);