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[209.132.180.67]) by mx.google.com with ESMTP id bc7si4392plb.55.2019.06.26.12.41.38; Wed, 26 Jun 2019 12:41:54 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=KOoNaQnz; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726370AbfFZTjn (ORCPT + 99 others); Wed, 26 Jun 2019 15:39:43 -0400 Received: from mail-io1-f65.google.com ([209.85.166.65]:44180 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726104AbfFZTjn (ORCPT ); Wed, 26 Jun 2019 15:39:43 -0400 Received: by mail-io1-f65.google.com with SMTP id s7so4687462iob.11 for ; Wed, 26 Jun 2019 12:39:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HrgKV2laxb7CmMhAO2Zht6dY5cjmqevbQFQ/CfbqMLo=; b=KOoNaQnzlS7is373aZlIpXHi9c/FdczNBYXNJFlghPA2DuSObQ02XSjoB1IECTklM+ lu+Dc+nt5KYYNp13+gCQ+cSPlInpBMLEywNBGsksqwRjnrv4SgUO4PXqNuruj9JYNsLm kz6tlMgIJDouZH1XfpYKhctzWZ+76XIHOprLbjuymNqrlW+9lhNJvZkyzXwBn0LCXAv1 bgQrnFzdo87+D0PZ6JlClu2ag5qEUE87IshPvZXHlnIwnO4AHs/bvDfaaqoDHucFvW0c JdK7yuvbRLz0qrXD7/fy4fHElKOQlRQjn69aL3tJlmmNO9FR5oavdTLDNvBKbt8YQRmt E+MQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HrgKV2laxb7CmMhAO2Zht6dY5cjmqevbQFQ/CfbqMLo=; b=JHi7O7xX4pWxQTGnv1WS5daRptCkEpilYoPaz7pEYEoKkE+3Tx4iO0nlRgPWEuA867 u9iHf3hm46FSsG6YH1oHLniuLr/L46Ub5j8IzEfZT9TqzyyOvntSvG89Xidee36fK+27 Iq8SUrCKpWw0UU7hP0hayfOLOlKMWoq/4bW/Dtz1rgPRz1XPmpex4H+GMZnv1VkimGJk AMUnFMtJPlHUnUGMhPHgegmeVplPH+fcz5yUYaY5b13HBI9o26EW7vOOcFzbJ3N0E3GW GkW4sdfRZy1Iji9WgRq2D2UBjvWflwqLpvczNwMg50Ga4xb7zgLbNGPyzIxLw4eU7D88 cM1Q== X-Gm-Message-State: APjAAAXyGNqHSjE/JPi79eZaXOSkrG6E2Olx0Ro568KLnEvPuQo3K44E NlH2F1ML+WoiSqt2a3DOY38jYHaPs1wRkZQeI3yFGNRO+qc= X-Received: by 2002:a02:3308:: with SMTP id c8mr4225629jae.103.1561577982127; Wed, 26 Jun 2019 12:39:42 -0700 (PDT) MIME-Version: 1.0 References: <20190621011941.186255-1-matthewgarrett@google.com> <20190621011941.186255-30-matthewgarrett@google.com> <20190626090748.23eba868@gandalf.local.home> In-Reply-To: <20190626090748.23eba868@gandalf.local.home> From: Matthew Garrett Date: Wed, 26 Jun 2019 12:39:31 -0700 Message-ID: Subject: Re: [PATCH V33 29/30] tracefs: Restrict tracefs when the kernel is locked down To: Steven Rostedt Cc: James Morris , linux-security@vger.kernel.org, Linux Kernel Mailing List , Linux API Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 26, 2019 at 6:07 AM Steven Rostedt wrote: > > On Thu, 20 Jun 2019 18:19:40 -0700 > Matthew Garrett wrote: > > +static const struct file_operations tracefs_proxy_file_operations = { > > + .read = default_read_file, > > + .write = default_write_file, > > + .open = default_open_file, > > + .llseek = noop_llseek, > > +}; > > This appears to be unused. Oops, yup - dropped. > > + dentry->d_fsdata = fops ? (void *)fops : > > + (void *)&tracefs_file_operations; > > + memcpy(proxy_fops, dentry->d_fsdata, sizeof(struct file_operations)); > > + proxy_fops->open = default_open_file; > > inode->i_mode = mode; > > - inode->i_fop = fops ? fops : &tracefs_file_operations; > > + inode->i_fop = proxy_fops; > > > I think the above would look cleaner as: > > > if (!fops) > fops = &tracefs_file_operations; > > dentry->d_fsdata = (void *)fops; > memcpy(proxy_fops, fops, sizeof(*proxy_fops); > proxy_fops->open = default_open_file; ACK.