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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 457CFC433DF for ; Wed, 13 May 2020 18:53:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDC9C2054F for ; Wed, 13 May 2020 18:53:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="IbEVDf1P" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732990AbgEMSxi (ORCPT ); Wed, 13 May 2020 14:53:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2390303AbgEMSxc (ORCPT ); Wed, 13 May 2020 14:53:32 -0400 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8851BC05BD0B for ; Wed, 13 May 2020 11:53:32 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id v12so720349wrp.12 for ; Wed, 13 May 2020 11:53:32 -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=pXu37DD6iE65dDGCF4WvK7cyvgiimEWOvvgpryvd52U=; b=IbEVDf1PZkcsC9qKSfRpq/TZXfimI98pReSCcaQgTPNl9HmndoODpa4MDeOulOvRz4 yCi4Y0M//sK1fidl4u5Podrn0hGfzM9JzccG27h3Bum61GNrk5w9Z1sOClL7Gns6+5GF NnqDrlIux2oiU+oQESCrAfiMljk+vnBzT/ypM= 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=pXu37DD6iE65dDGCF4WvK7cyvgiimEWOvvgpryvd52U=; b=ISJTkwxoR0J30t/Ggd3uhLILqH7X5NeOSny6CvyoSmlWsBH0NniPyGxTD1JHdTdoBa ZyrT5gQpavK0iPFsCgOT6pupmudJqzK/ocbflx+iQfT3rubgzHaJOLWGbJrq6CopLFfr 9vs20qFsTBvaJ9O5n+VXHonN1NVdAqoEgdetiQm6ovWIlg+t3dNG38NTSKfcwmJ+JLKf ODNKLvsRIjG4Rr7apmCZskmP1n5ThGAshUzcwhBAy5aNrSRsREpNC6RmvRDnTZgbhPTL BAm3FAz9R8d9EiNpYzaf/HLklyB6mBqyKCyGHwTXk/X7a0+OD42kuVD+N+EKRZPLk41M m4JQ== X-Gm-Message-State: AOAM530huGEReNKePTb4oCPM/AhpepuXgdcNLm8FHLdoDxVai/RoELip KaePUL74DsxlLAO6cGoegU37XI/Aqg4a3ALNsx7Q8/3KtrRhFpB6Oud6KR2k8bxVECvNAfJ17GP Ub4fI/MyUW5At/uLmojUV0frOfap+SgeXe51x8Dwi4pPDcpoMS3IWhquOg4VUxneI4xXgqqmZgw 7J/49tm7V4gRiV X-Google-Smtp-Source: ABdhPJyQTNm1BSKNK4nPH8PwhT168mr3Et0SlCcd67hBnuW+VdEO/ieVYFVuvkPPR1fp/Uk3isIZEg== X-Received: by 2002:adf:a151:: with SMTP id r17mr761655wrr.161.1589396010916; Wed, 13 May 2020 11:53:30 -0700 (PDT) Received: from [10.136.13.65] ([192.19.228.250]) by smtp.gmail.com with ESMTPSA id i17sm37309331wml.23.2020.05.13.11.53.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 13 May 2020 11:53:30 -0700 (PDT) Subject: Re: [PATCH v5 1/7] fs: introduce kernel_pread_file* support To: Mimi Zohar , Luis Chamberlain , Greg Kroah-Hartman , David Brown , Alexander Viro , Shuah Khan , bjorn.andersson@linaro.org, Shuah Khan , Arnd Bergmann Cc: "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-fsdevel@vger.kernel.org, BCM Kernel Feedback , Olof Johansson , Andrew Morton , Dan Carpenter , Colin Ian King , Kees Cook , Takashi Iwai , linux-kselftest@vger.kernel.org, Andy Gross , linux-security-module , linux-integrity References: <20200508002739.19360-1-scott.branden@broadcom.com> <20200508002739.19360-2-scott.branden@broadcom.com> <1589395153.5098.158.camel@kernel.org> From: Scott Branden Message-ID: <0e6b5f65-8c61-b02e-7d35-b4ae52aebcf3@broadcom.com> Date: Wed, 13 May 2020 11:53:23 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <1589395153.5098.158.camel@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Hi Mimi, On 2020-05-13 11:39 a.m., Mimi Zohar wrote: > [Cc'ing linux-security-module, linux-integrity] > > On Thu, 2020-05-07 at 17:27 -0700, Scott Branden wrote: >> Add kernel_pread_file* support to kernel to allow for partial read >> of files with an offset into the file. Existing kernel_read_file >> functions call new kernel_pread_file functions with offset=0 and >> flags=KERNEL_PREAD_FLAG_WHOLE. >> >> Signed-off-by: Scott Branden >> --- > > >> @@ -941,14 +955,16 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size, The checkpatch shows this as kernel_read_file when it is actually the new function kernel_pread_file. Please see the call to kernel_pread_file from kernel_read_file in the complete patch rather this snippet. >> >> if (bytes == 0) >> break; >> + >> + buf_pos += bytes; >> } >> >> - if (pos != i_size) { >> + if (pos != read_end) { >> ret = -EIO; >> goto out_free; >> } >> >> - ret = security_kernel_post_read_file(file, *buf, i_size, id); >> + ret = security_kernel_post_read_file(file, *buf, alloc_size, id); >> if (!ret) >> *size = pos; > Prior to the patch set that introduced this security hook, firmware > would be read twice, once for measuring/appraising the firmware and > again reading the file contents into memory.  Partial reads will break > both IMA's measuring the file and appraising the file signatures. The partial file read support is needed for request_firmware_into_buf from drivers.  The EXPORT_SYMBOL_GPL is being removed so that there can be no abuse of the partial file read support.  Such file integrity checks are not needed for this use case.  The partial file (firmware image) is actually downloaded in portions and verified on the device it is loaded to. Regards,  Scott