From patchwork Mon Sep 26 17:30:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Mimi Zohar X-Patchwork-Id: 9351059 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6925B6086A for ; Mon, 26 Sep 2016 17:31:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5B57C28AF0 for ; Mon, 26 Sep 2016 17:31:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 507A528AF6; Mon, 26 Sep 2016 17:31:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A286B28AF0 for ; Mon, 26 Sep 2016 17:31:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161682AbcIZRb2 (ORCPT ); Mon, 26 Sep 2016 13:31:28 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:33073 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161200AbcIZRbZ (ORCPT ); Mon, 26 Sep 2016 13:31:25 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8QHSlL1053624 for ; Mon, 26 Sep 2016 13:31:25 -0400 Received: from e28smtp02.in.ibm.com (e28smtp02.in.ibm.com [125.16.236.2]) by mx0a-001b2d01.pphosted.com with ESMTP id 25q58brdgm-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 26 Sep 2016 13:31:25 -0400 Received: from localhost by e28smtp02.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 26 Sep 2016 23:01:20 +0530 Received: from d28relay08.in.ibm.com (d28relay08.in.ibm.com [9.184.220.159]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id 90AEC125805B; Mon, 26 Sep 2016 23:01:40 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay08.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u8QHV95g9109670; Mon, 26 Sep 2016 23:01:09 +0530 Received: from d28av04.in.ibm.com (localhost [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u8QHVEuA009634; Mon, 26 Sep 2016 23:01:19 +0530 Received: from localhost.localdomain.localdomain (dhcp-9-2-51-4.watson.ibm.com [9.2.51.4]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u8QHUdYd008011; Mon, 26 Sep 2016 23:01:11 +0530 From: Mimi Zohar To: linux-security-module Cc: Mimi Zohar , "Eric W. Biederman" , linux-ima-devel@lists.sourceforge.net, Dave Young , kexec@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Thiago Jung Bauermann , Andrew Morton Subject: [PATCH v5 06/10] ima: on soft reboot, save the measurement list Date: Mon, 26 Sep 2016 13:30:25 -0400 X-Mailer: git-send-email 2.1.0 In-Reply-To: <1474911029-6372-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1474911029-6372-1-git-send-email-zohar@linux.vnet.ibm.com> MIME-Version: 1.0 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16092617-0004-0000-0000-000003370220 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16092617-0005-0000-0000-00000F991B4C Message-Id: <1474911029-6372-7-git-send-email-zohar@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-09-26_08:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609020000 definitions=main-1609260329 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP The TPM PCRs are only reset on a hard reboot. In order to validate a TPM's quote after a soft reboot (eg. kexec -e), the IMA measurement list of the running kernel must be saved and restored on boot. This patch uses the kexec buffer passing mechanism to pass the serialized IMA binary_runtime_measurements to the next kernel. Changelog v5: - move writing the IMA measurement list to kexec load and remove from kexec execute. - remove registering notifier to call update on kexec execute - add includes needed by code in this patch to ima_kexec.c (Thiago) - fold patch "ima: serialize the binary_runtime_measurements" into this patch. Changelog v4: - Revert the skip_checksum change.  Instead calculate the checksum with the measurement list segment, on update validate the existing checksum before re-calulating a new checksum with the updated measurement list. Changelog v3: - Request a kexec segment for storing the measurement list a half page, not a full page, more than needed for additional measurements. - Added binary_runtime_size overflow test - Limit maximum number of pages needed for kexec_segment_size to half of totalram_pages. (Dave Young) Changelog v2: - Fix build issue by defining a stub ima_add_kexec_buffer and stub struct kimage when CONFIG_IMA=n and CONFIG_IMA_KEXEC=n. (Fenguang Wu) - removed kexec_add_handover_buffer() checksum argument. - added skip_checksum member to kexec_buf - only register reboot notifier once Changelog v1: - updated to call IMA functions (Mimi) - move code from ima_template.c to ima_kexec.c (Mimi) Signed-off-by: Thiago Jung Bauermann Signed-off-by: Mimi Zohar --- include/linux/ima.h | 12 ++++ kernel/kexec_file.c | 4 ++ security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_fs.c | 2 +- security/integrity/ima/ima_kexec.c | 117 +++++++++++++++++++++++++++++++++++++ 5 files changed, 135 insertions(+), 1 deletion(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index 0eb7c2e..7f6952f 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -11,6 +11,7 @@ #define _LINUX_IMA_H #include +#include struct linux_binprm; #ifdef CONFIG_IMA @@ -23,6 +24,10 @@ extern int ima_post_read_file(struct file *file, void *buf, loff_t size, enum kernel_read_file_id id); extern void ima_post_path_mknod(struct dentry *dentry); +#ifdef CONFIG_IMA_KEXEC +extern void ima_add_kexec_buffer(struct kimage *image); +#endif + #else static inline int ima_bprm_check(struct linux_binprm *bprm) { @@ -62,6 +67,13 @@ static inline void ima_post_path_mknod(struct dentry *dentry) #endif /* CONFIG_IMA */ +#ifndef CONFIG_IMA_KEXEC +struct kimage; + +static inline void ima_add_kexec_buffer(struct kimage *image) +{} +#endif + #ifdef CONFIG_IMA_APPRAISE extern void ima_inode_post_setattr(struct dentry *dentry); extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name, diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 0c2df7f..b56a558 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -132,6 +133,9 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, return ret; image->kernel_buf_len = size; + /* IMA needs to pass the measurement list to the next kernel. */ + ima_add_kexec_buffer(image); + /* Call arch image probe handlers */ ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, image->kernel_buf_len); diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index ea1dcc4..139dec6 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -143,6 +143,7 @@ void ima_print_digest(struct seq_file *m, u8 *digest, u32 size); struct ima_template_desc *ima_template_desc_current(void); int ima_restore_measurement_entry(struct ima_template_entry *entry); int ima_restore_measurement_list(loff_t bufsize, void *buf); +int ima_measurements_show(struct seq_file *m, void *v); unsigned long ima_get_binary_runtime_size(void); int ima_init_template(void); diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c index c07a384..66e5dd5 100644 --- a/security/integrity/ima/ima_fs.c +++ b/security/integrity/ima/ima_fs.c @@ -116,7 +116,7 @@ void ima_putc(struct seq_file *m, void *data, int datalen) * [eventdata length] * eventdata[n]=template specific data */ -static int ima_measurements_show(struct seq_file *m, void *v) +int ima_measurements_show(struct seq_file *m, void *v) { /* the list never shrinks, so we don't need a lock here */ struct ima_queue_entry *qe = v; diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c index 36afd0f..2c4824a 100644 --- a/security/integrity/ima/ima_kexec.c +++ b/security/integrity/ima/ima_kexec.c @@ -10,8 +10,125 @@ * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ +#include +#include +#include #include "ima.h" +#ifdef CONFIG_IMA_KEXEC +static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, + unsigned long segment_size) +{ + struct ima_queue_entry *qe; + struct seq_file file; + struct ima_kexec_hdr khdr = { + .version = 1, .buffer_size = 0, .count = 0}; + int ret = 0; + + /* segment size can't change between kexec load and execute */ + file.buf = vmalloc(segment_size); + if (!file.buf) { + ret = -ENOMEM; + goto out; + } + + file.size = segment_size; + file.read_pos = 0; + file.count = sizeof(khdr); /* reserved space */ + + list_for_each_entry_rcu(qe, &ima_measurements, later) { + if (file.count < file.size) { + khdr.count++; + ima_measurements_show(&file, qe); + } else { + ret = -EINVAL; + break; + } + } + + if (ret < 0) + goto out; + + /* + * fill in reserved space with some buffer details + * (eg. version, buffer size, number of measurements) + */ + khdr.buffer_size = file.count; + memcpy(file.buf, &khdr, sizeof(khdr)); + print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE, + 16, 1, file.buf, + file.count < 100 ? file.count : 100, true); + + *buffer_size = file.count; + *buffer = file.buf; +out: + if (ret == -EINVAL) + vfree(file.buf); + return ret; +} + +/* + * Called during kexec_file_load so that IMA can add a segment to the kexec + * image for the measurement list for the next kernel. + * + * This function assumes that kexec_mutex is held. + */ +void ima_add_kexec_buffer(struct kimage *image) +{ + struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE, + .buf_min = 0, .buf_max = ULONG_MAX, + .top_down = true }; + unsigned long binary_runtime_size; + + /* use more understandable variable names than defined in kbuf */ + void *kexec_buffer = NULL; + size_t kexec_buffer_size; + size_t kexec_segment_size; + int ret; + + /* + * Reserve an extra half page of memory for additional measurements + * added during the kexec load. + */ + binary_runtime_size = ima_get_binary_runtime_size(); + if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) + kexec_segment_size = ULONG_MAX; + else + kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + + PAGE_SIZE / 2, PAGE_SIZE); + if ((kexec_segment_size == ULONG_MAX) || + ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages / 2)) { + pr_err("Binary measurement list too large.\n"); + return; + } + + ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, + kexec_segment_size); + if (!kexec_buffer) { + pr_err("Not enough memory for the kexec measurement buffer.\n"); + return; + } + + kbuf.buffer = kexec_buffer; + kbuf.bufsz = kexec_buffer_size; + kbuf.memsz = kexec_segment_size; + ret = kexec_add_buffer(&kbuf); + if (ret) { + pr_err("Error passing over kexec measurement buffer.\n"); + return; + } + + ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size); + if (ret) { + pr_err("Error passing over kexec measurement buffer.\n"); + return; + } + + pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", + kbuf.mem); +} +#endif /* IMA_KEXEC */ + /* * Restore the measurement list from the previous kernel. */