From patchwork Thu Nov 12 16:10:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 11900591 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A68BA138B for ; Thu, 12 Nov 2020 16:11:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C7E022248 for ; Thu, 12 Nov 2020 16:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728756AbgKLQLf (ORCPT ); Thu, 12 Nov 2020 11:11:35 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2096 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728426AbgKLQLf (ORCPT ); Thu, 12 Nov 2020 11:11:35 -0500 Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4CX64K1xg2z67Ks4; Fri, 13 Nov 2020 00:09:37 +0800 (CST) Received: from roberto-HP-EliteDesk-800-G2-DM-65W.huawei.com (10.204.65.161) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Thu, 12 Nov 2020 17:11:33 +0100 From: Roberto Sassu To: CC: , , , , Roberto Sassu Subject: [PATCH] ima: Set and clear FMODE_CAN_READ in ima_calc_file_hash() Date: Thu, 12 Nov 2020 17:10:05 +0100 Message-ID: <20201112161005.6192-1-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.27.GIT MIME-Version: 1.0 X-Originating-IP: [10.204.65.161] X-ClientProxiedBy: lhreml715-chm.china.huawei.com (10.201.108.66) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Commit a1f9b1c0439db ("integrity/ima: switch to using __kernel_read") replaced the __vfs_read() call in integrity_kernel_read() with __kernel_read(), a new helper introduced by commit 61a707c543e2a ("fs: add a __kernel_read helper"). Since the new helper requires that also the FMODE_CAN_READ flag is set in file->f_mode, this patch saves the original f_mode and sets the flag if the file descriptor has the necessary file operation. Lastly, it restores the original f_mode at the end of ima_calc_file_hash(). Signed-off-by: Roberto Sassu --- security/integrity/ima/ima_crypto.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 21989fa0c107..22ed86a0c964 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -537,6 +537,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) loff_t i_size; int rc; struct file *f = file; + fmode_t saved_mode; bool new_file_instance = false, modified_mode = false; /* @@ -550,7 +551,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) } /* Open a new file instance in O_RDONLY if we cannot read */ - if (!(file->f_mode & FMODE_READ)) { + if (!(file->f_mode & FMODE_READ) || !(file->f_mode & FMODE_CAN_READ)) { int flags = file->f_flags & ~(O_WRONLY | O_APPEND | O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL); flags |= O_RDONLY; @@ -562,7 +563,10 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) */ pr_info_ratelimited("Unable to reopen file for reading.\n"); f = file; + saved_mode = f->f_mode; f->f_mode |= FMODE_READ; + if (likely(file->f_op->read || file->f_op->read_iter)) + f->f_mode |= FMODE_CAN_READ; modified_mode = true; } else { new_file_instance = true; @@ -582,7 +586,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) if (new_file_instance) fput(f); else if (modified_mode) - f->f_mode &= ~FMODE_READ; + f->f_mode = saved_mode; return rc; }