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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 796F2C433DF for ; Fri, 3 Jul 2020 06:02:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5742A20A8B for ; Fri, 3 Jul 2020 06:02:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593756135; bh=HIbJqRSFMbUgRkZxtvG3aCNp0wd5skVeN76Mqr6ZKlI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=QOWkZ8mEOKO+S6wW9igrv70JVRJsUzYgSHjQNWo0WnCQsxjJ71Xbpsa4b8CWKVHOX Dt3fD7k9ysgb7MVu9HZ4G/4WkNy8qf2BAQV9gsQOBBlgszc/inxv7wq2bAMfLaVKqW uIGEH5+DbZS5REh9lmh5OFCpyfY1wpqyfDiyEG2A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726208AbgGCGCM (ORCPT ); Fri, 3 Jul 2020 02:02:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:57942 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725648AbgGCGCL (ORCPT ); Fri, 3 Jul 2020 02:02:11 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E82F220771; Fri, 3 Jul 2020 06:02:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593756130; bh=HIbJqRSFMbUgRkZxtvG3aCNp0wd5skVeN76Mqr6ZKlI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ks5iQI9moJ0UD4VvJm9ozWnH28lwPOVOnLsnopJbPFPBQsEaiok8uVnUYwa7UR9Em zT/zdo82iWrWjIV6wKofQC1UNdIGd6arNQdcSpV/VEzGzCyBuTWsW+bcVIydzXWYF+ qweWZjyKubece8hBub0Wh9BvVjYTG8pxDay2iy7Q= Date: Fri, 3 Jul 2020 08:02:07 +0200 From: Greg Kroah-Hartman To: Kees Cook Cc: Dominik Czarnota , stable@vger.kernel.org, Jessica Yu , Linus Torvalds , Andrew Morton , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , KP Singh , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Masami Hiramatsu , Jakub Kicinski , "Steven Rostedt (VMware)" , Dmitry Safonov <0x7f454c46@gmail.com>, Will Deacon , Alexey Dobriyan , Marc Zyngier , Masahiro Yamada , Al Viro , Matteo Croce , Edward Cree , Nicolas Dichtel , Alexander Lobakin , Thomas Richter , Ingo Molnar , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/5] module: Refactor section attr into bin attribute Message-ID: <20200703060207.GA6344@kroah.com> References: <20200702232638.2946421-1-keescook@chromium.org> <20200702232638.2946421-3-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200702232638.2946421-3-keescook@chromium.org> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Jul 02, 2020 at 04:26:35PM -0700, Kees Cook wrote: > In order to gain access to the open file's f_cred for kallsym visibility > permission checks, refactor the module section attributes to use the > bin_attribute instead of attribute interface. Additionally removes the > redundant "name" struct member. > > Cc: stable@vger.kernel.org > Signed-off-by: Kees Cook > --- > kernel/module.c | 45 ++++++++++++++++++++++++--------------------- > 1 file changed, 24 insertions(+), 21 deletions(-) > > diff --git a/kernel/module.c b/kernel/module.c > index a5022ae84e50..9e2954519259 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -1510,8 +1510,7 @@ static inline bool sect_empty(const Elf_Shdr *sect) > } > > struct module_sect_attr { > - struct module_attribute mattr; > - char *name; > + struct bin_attribute battr; > unsigned long address; > }; > > @@ -1521,11 +1520,16 @@ struct module_sect_attrs { > struct module_sect_attr attrs[]; > }; > > -static ssize_t module_sect_show(struct module_attribute *mattr, > - struct module_kobject *mk, char *buf) > +static ssize_t module_sect_read(struct file *file, struct kobject *kobj, > + struct bin_attribute *battr, > + char *buf, loff_t pos, size_t count) > { > struct module_sect_attr *sattr = > - container_of(mattr, struct module_sect_attr, mattr); > + container_of(battr, struct module_sect_attr, battr); > + > + if (pos != 0) > + return -EINVAL; > + > return sprintf(buf, "0x%px\n", kptr_restrict < 2 ? > (void *)sattr->address : NULL); > } > @@ -1535,7 +1539,7 @@ static void free_sect_attrs(struct module_sect_attrs *sect_attrs) > unsigned int section; > > for (section = 0; section < sect_attrs->nsections; section++) > - kfree(sect_attrs->attrs[section].name); > + kfree(sect_attrs->attrs[section].battr.attr.name); > kfree(sect_attrs); > } > > @@ -1544,42 +1548,41 @@ static void add_sect_attrs(struct module *mod, const struct load_info *info) > unsigned int nloaded = 0, i, size[2]; > struct module_sect_attrs *sect_attrs; > struct module_sect_attr *sattr; > - struct attribute **gattr; > + struct bin_attribute **gattr; > > /* Count loaded sections and allocate structures */ > for (i = 0; i < info->hdr->e_shnum; i++) > if (!sect_empty(&info->sechdrs[i])) > nloaded++; > size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded), > - sizeof(sect_attrs->grp.attrs[0])); > - size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.attrs[0]); > + sizeof(sect_attrs->grp.bin_attrs[0])); > + size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]); > sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL); > if (sect_attrs == NULL) > return; > > /* Setup section attributes. */ > sect_attrs->grp.name = "sections"; > - sect_attrs->grp.attrs = (void *)sect_attrs + size[0]; > + sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0]; > > sect_attrs->nsections = 0; > sattr = §_attrs->attrs[0]; > - gattr = §_attrs->grp.attrs[0]; > + gattr = §_attrs->grp.bin_attrs[0]; > for (i = 0; i < info->hdr->e_shnum; i++) { > Elf_Shdr *sec = &info->sechdrs[i]; > if (sect_empty(sec)) > continue; > + sysfs_bin_attr_init(&sattr->battr); > sattr->address = sec->sh_addr; > - sattr->name = kstrdup(info->secstrings + sec->sh_name, > - GFP_KERNEL); > - if (sattr->name == NULL) > + sattr->battr.attr.name = > + kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL); > + if (sattr->battr.attr.name == NULL) > goto out; > sect_attrs->nsections++; > - sysfs_attr_init(&sattr->mattr.attr); > - sattr->mattr.show = module_sect_show; > - sattr->mattr.store = NULL; > - sattr->mattr.attr.name = sattr->name; > - sattr->mattr.attr.mode = S_IRUSR; > - *(gattr++) = &(sattr++)->mattr.attr; > + sattr->battr.read = module_sect_read; > + sattr->battr.size = 3 /* "0x", "\n" */ + (BITS_PER_LONG / 4); > + sattr->battr.attr.mode = 0400; > + *(gattr++) = &(sattr++)->battr; > } > *gattr = NULL; > > @@ -1669,7 +1672,7 @@ static void add_notes_attrs(struct module *mod, const struct load_info *info) > continue; > if (info->sechdrs[i].sh_type == SHT_NOTE) { > sysfs_bin_attr_init(nattr); > - nattr->attr.name = mod->sect_attrs->attrs[loaded].name; > + nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name; > nattr->attr.mode = S_IRUGO; > nattr->size = info->sechdrs[i].sh_size; > nattr->private = (void *) info->sechdrs[i].sh_addr; > -- > 2.25.1 > They get a correct "size" value now, nice! Reviewed-by: Greg Kroah-Hartman