From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52461 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752389AbdFUSUU (ORCPT ); Wed, 21 Jun 2017 14:20:20 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5LIIUFu074001 for ; Wed, 21 Jun 2017 14:20:19 -0400 Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) by mx0a-001b2d01.pphosted.com with ESMTP id 2b7rm5s4wa-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 21 Jun 2017 14:20:19 -0400 Received: from localhost by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 22 Jun 2017 04:20:17 +1000 From: Mimi Zohar To: Christoph Hellwig , Al Viro Cc: Mimi Zohar , James Morris , linux-fsdevel@vger.kernel.org, linux-ima-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org Subject: [PATCH v2 10/10] ima: use existing read file operation method to calculate file hash Date: Wed, 21 Jun 2017 14:18:30 -0400 In-Reply-To: <1498069110-10009-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1498069110-10009-1-git-send-email-zohar@linux.vnet.ibm.com> Message-Id: <1498069110-10009-11-git-send-email-zohar@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: The builtin "ima_tcb" policy measures all files read by root. This policy includes, for example, files on efivars. Since some files on these filesystems were previously measured (eg. OsIndicationsSupported), not measuring them would change the PCR hash value(s), potentially breaking userspace. The few filesystems that currently define the ->read file operation method, either call seq_read() or have a filesystem specific ->read method. None of them, at least in the fs directory, take the i_rwsem. For filesystems that do not define the ->integrity_read file operation method and have a ->read method, this patch calls the ->read method to calculate the file hash. Signed-off-by: Mimi Zohar --- security/integrity/iint.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/security/integrity/iint.c b/security/integrity/iint.c index df04f35a1d40..75c3cef5fd01 100644 --- a/security/integrity/iint.c +++ b/security/integrity/iint.c @@ -189,20 +189,29 @@ int integrity_kernel_read(struct file *file, loff_t offset, struct kvec iov = { .iov_base = addr, .iov_len = count }; struct kiocb kiocb; struct iov_iter iter; - ssize_t ret; + ssize_t ret = -EBADF; lockdep_assert_held(&inode->i_rwsem); if (!(file->f_mode & FMODE_READ)) return -EBADF; - if (!file->f_op->integrity_read) - return -EBADF; init_sync_kiocb(&kiocb, file); kiocb.ki_pos = offset; iov_iter_kvec(&iter, READ | ITER_KVEC, &iov, 1, count); - ret = file->f_op->integrity_read(&kiocb, &iter); + if (file->f_op->integrity_read) { + ret = file->f_op->integrity_read(&kiocb, &iter); + } else if (file->f_op->read) { + mm_segment_t old_fs; + char __user *buf = (char __user *)addr; + + old_fs = get_fs(); + set_fs(get_ds()); + ret = file->f_op->read(file, buf, count, &offset); + set_fs(old_fs); + } + BUG_ON(ret == -EIOCBQUEUED); return ret; } -- 2.7.4