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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 0515FC433E4 for ; Fri, 10 Jul 2020 21:00:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD9FA2068F for ; Fri, 10 Jul 2020 21:00:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="CSG6ET/D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726299AbgGJVAs (ORCPT ); Fri, 10 Jul 2020 17:00:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726286AbgGJVAq (ORCPT ); Fri, 10 Jul 2020 17:00:46 -0400 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A700C08E6DC for ; Fri, 10 Jul 2020 14:00:46 -0700 (PDT) Received: by mail-pf1-x442.google.com with SMTP id j20so3058778pfe.5 for ; Fri, 10 Jul 2020 14:00:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=cyPZ2F8Elm/X30AvLL1oEN+KGMJ5jtRTB8rf0GQJuQU=; b=CSG6ET/DEoTdyvRO4iN3bYezY58ajzJ63SpVhvOqXxT0zPMKr+VjjZhxRiQvdQVTcK pP5iJk8t1/K01jHv8rehu+9M45OI1F12or/xjemjXMkwwEAD1idXHk5ol+2C1yDoi44t u1Sjhfh5SGd5lW408UKk6ZZDogLt9jqa//FtI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=cyPZ2F8Elm/X30AvLL1oEN+KGMJ5jtRTB8rf0GQJuQU=; b=QrRGoQXeNLFYyiteGqLAsCa0OGsIFET2QP8bh2Z3zlQzHszk5+kH2v3D4jYksINkOy Ohl+98a9PA3Swh77iLXRV2KssstKZqUvZE+nifSO+6YPU5I/FyKI9OoV7XmJrNohUq79 u7sfWUVh9TFu8EOn9ahlz6SBRw2nca7VPk/w76tT+DQwRkqiKNBabyoUwwtoQa8DhSVf RNzzGGEd6khlILJ50pJ8kvWyVpRfbbeLNN8jSbnc/aTflfBO9ZrTX0iWfeGdqB8xA/Wr Cy4QOlE01dgZHqbVBbi6/hm2zb9NAW0d+ExZnEs0XpKkNCCt1nNo39/2h2wJCmIJgGgz l8wQ== X-Gm-Message-State: AOAM531X2MOzlNWG09gzAwNoqP/Sx+dreaxNNfL8I8Aal3Daz3Gg2Qvh Y5glxu3wegyXM59aPp74Og99Rx80SXQ92w== X-Google-Smtp-Source: ABdhPJx9N2FJKG78sh217VkA3T8P4l6LMqcB/e6Ykg2KomvFC7EXnwO8oLP7kDriJaQKbqt4vg18jQ== X-Received: by 2002:a63:3c2:: with SMTP id 185mr61414088pgd.46.1594414845795; Fri, 10 Jul 2020 14:00:45 -0700 (PDT) Received: from [10.136.13.65] ([192.19.228.250]) by smtp.gmail.com with ESMTPSA id e28sm6852810pfm.177.2020.07.10.14.00.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 10 Jul 2020 14:00:44 -0700 (PDT) Subject: Re: [PATCH 2/4] fs: Remove FIRMWARE_PREALLOC_BUFFER from kernel_read_file() enums To: Kees Cook , James Morris Cc: Luis Chamberlain , Mimi Zohar , Greg Kroah-Hartman , "Rafael J. Wysocki" , Alexander Viro , Jessica Yu , Dmitry Kasatkin , "Serge E. Hallyn" , Casey Schaufler , "Eric W. Biederman" , Peter Zijlstra , Matthew Garrett , David Howells , Mauro Carvalho Chehab , Randy Dunlap , "Joel Fernandes (Google)" , KP Singh , Dave Olsthoorn , Hans de Goede , Peter Jones , Andrew Morton , Stephen Boyd , Paul Moore , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org References: <20200707081926.3688096-1-keescook@chromium.org> <20200707081926.3688096-3-keescook@chromium.org> From: Scott Branden Message-ID: <3fdb3c53-7471-14d8-ce6a-251d8b660b8a@broadcom.com> Date: Fri, 10 Jul 2020 14:00:32 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200707081926.3688096-3-keescook@chromium.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Hi Kees, This patch fails during booting of my system - see below. On 2020-07-07 1:19 a.m., Kees Cook wrote: > FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs > that are interested in filtering between types of things. The "how" > should be an internal detail made uninteresting to the LSMs. > > Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer") > Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)") > Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)") > Signed-off-by: Kees Cook > --- > drivers/base/firmware_loader/main.c | 5 ++--- > fs/exec.c | 7 ++++--- > include/linux/fs.h | 2 +- > security/integrity/ima/ima_main.c | 6 ++---- > 4 files changed, 9 insertions(+), 11 deletions(-) > > diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c > index ca871b13524e..c2f57cedcd6f 100644 > --- a/drivers/base/firmware_loader/main.c > +++ b/drivers/base/firmware_loader/main.c > @@ -465,14 +465,12 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > int i, len; > int rc = -ENOENT; > char *path; > - enum kernel_read_file_id id = READING_FIRMWARE; > size_t msize = INT_MAX; > void *buffer = NULL; > > /* Already populated data member means we're loading into a buffer */ > if (!decompress && fw_priv->data) { > buffer = fw_priv->data; > - id = READING_FIRMWARE_PREALLOC_BUFFER; > msize = fw_priv->allocated_size; > } > > @@ -496,7 +494,8 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv, > > /* load firmware files from the mount namespace of init */ > rc = kernel_read_file_from_path_initns(path, &buffer, > - &size, msize, id); > + &size, msize, > + READING_FIRMWARE); > if (rc) { > if (rc != -ENOENT) > dev_warn(device, "loading %s failed with error %d\n", > diff --git a/fs/exec.c b/fs/exec.c > index e6e8a9a70327..2bf549757ce7 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -927,6 +927,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > { > loff_t i_size, pos; > ssize_t bytes = 0; > + void *allocated = NULL; > int ret; > > if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0) > @@ -950,8 +951,8 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > goto out; > } > > - if (id != READING_FIRMWARE_PREALLOC_BUFFER) > - *buf = vmalloc(i_size); > + if (!*buf) The assumption that *buf is always NULL when id != READING_FIRMWARE_PREALLOC_BUFFER doesn't appear to be correct. I get unhandled page faults due to this change on boot. > + *buf = allocated = vmalloc(i_size); > if (!*buf) { > ret = -ENOMEM; > goto out; > @@ -980,7 +981,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, > > out_free: > if (ret < 0) { > - if (id != READING_FIRMWARE_PREALLOC_BUFFER) { > + if (allocated) { > vfree(*buf); > *buf = NULL; > } > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 3f881a892ea7..95fc775ed937 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2993,10 +2993,10 @@ static inline void i_readcount_inc(struct inode *inode) > #endif > extern int do_pipe_flags(int *, int); > > +/* This is a list of *what* is being read, not *how*. */ > #define __kernel_read_file_id(id) \ > id(UNKNOWN, unknown) \ > id(FIRMWARE, firmware) \ > - id(FIRMWARE_PREALLOC_BUFFER, firmware) \ > id(FIRMWARE_EFI_EMBEDDED, firmware) \ > id(MODULE, kernel-module) \ > id(KEXEC_IMAGE, kexec-image) \ > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index c1583d98c5e5..f80ee4ce4669 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -611,19 +611,17 @@ void ima_post_path_mknod(struct dentry *dentry) > int ima_read_file(struct file *file, enum kernel_read_file_id read_id) > { > /* > - * READING_FIRMWARE_PREALLOC_BUFFER > - * > * Do devices using pre-allocated memory run the risk of the > * firmware being accessible to the device prior to the completion > * of IMA's signature verification any more than when using two > - * buffers? > + * buffers? It may be desirable to include the buffer address > + * in this API and walk all the dma_map_single() mappings to check. > */ > return 0; > } > > const int read_idmap[READING_MAX_ID] = { > [READING_FIRMWARE] = FIRMWARE_CHECK, > - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK, > [READING_MODULE] = MODULE_CHECK, > [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK, > [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,