From patchwork Tue Aug 30 17:45:05 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thiago Jung Bauermann X-Patchwork-Id: 9305827 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 535D960756 for ; Tue, 30 Aug 2016 17:48:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 46DEA28CE9 for ; Tue, 30 Aug 2016 17:48:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B65128CEB; Tue, 30 Aug 2016 17:48:04 +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 777D728CE9 for ; Tue, 30 Aug 2016 17:48:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933067AbcH3RsB (ORCPT ); Tue, 30 Aug 2016 13:48:01 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35856 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933652AbcH3Rp0 (ORCPT ); Tue, 30 Aug 2016 13:45:26 -0400 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u7UHhd1Y071525 for ; Tue, 30 Aug 2016 13:45:25 -0400 Received: from e24smtp02.br.ibm.com (e24smtp02.br.ibm.com [32.104.18.86]) by mx0a-001b2d01.pphosted.com with ESMTP id 2558r5d6j7-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 30 Aug 2016 13:45:25 -0400 Received: from localhost by e24smtp02.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Tue, 30 Aug 2016 14:45:21 -0300 X-IBM-Helo: d24dlp02.br.ibm.com X-IBM-MailFrom: bauerman@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org; linux-security-module@vger.kernel.org Received: from d24relay02.br.ibm.com (d24relay02.br.ibm.com [9.13.184.26]) by d24dlp02.br.ibm.com (Postfix) with ESMTP id EE0EB1DC006D; Tue, 30 Aug 2016 13:45:10 -0400 (EDT) Received: from d24av05.br.ibm.com (d24av05.br.ibm.com [9.18.232.44]) by d24relay02.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u7UHjKg122217006; Tue, 30 Aug 2016 14:45:20 -0300 Received: from d24av05.br.ibm.com (localhost [127.0.0.1]) by d24av05.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u7UHjJ0S016013; Tue, 30 Aug 2016 14:45:20 -0300 Received: from hactar.ibm.com (lcfurno.br.ibm.com [9.18.203.1] (may be forged)) by d24av05.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u7UHjAVc015449; Tue, 30 Aug 2016 14:45:17 -0300 From: Thiago Jung Bauermann To: kexec@lists.infradead.org Cc: linux-security-module@vger.kernel.org, linux-ima-devel@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Eric Biederman , Dave Young , Vivek Goyal , Baoquan He , Michael Ellerman , Stewart Smith , Mimi Zohar , Eric Richter , Andrew Morton , Balbir Singh , Thiago Jung Bauermann Subject: [PATCH v4 5/5] IMA: Demonstration code for kexec buffer passing. Date: Tue, 30 Aug 2016 14:45:05 -0300 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1472579105-26296-1-git-send-email-bauerman@linux.vnet.ibm.com> References: <1472579105-26296-1-git-send-email-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16083017-0020-0000-0000-00000236AF67 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16083017-0021-0000-0000-00003027634A Message-Id: <1472579105-26296-6-git-send-email-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-08-30_07:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=38 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608300169 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP This shows how kernel code can use the kexec buffer passing mechanism to pass information to the next kernel. This patch is not intended to be committed. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Thiago Jung Bauermann Signed-off-by: Andrew Morton --- include/linux/ima.h | 11 +++++ kernel/kexec_file.c | 4 ++ security/integrity/ima/ima.h | 5 +++ security/integrity/ima/ima_init.c | 26 +++++++++++ security/integrity/ima/ima_template.c | 85 +++++++++++++++++++++++++++++++++++ 5 files changed, 131 insertions(+) diff --git a/include/linux/ima.h b/include/linux/ima.h index 0eb7c2e7f0d6..96528d007139 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_KEXEC_FILE +extern void ima_add_kexec_buffer(struct kimage *image); +#endif + #else static inline int ima_bprm_check(struct linux_binprm *bprm) { @@ -60,6 +65,12 @@ static inline void ima_post_path_mknod(struct dentry *dentry) return; } +#ifdef CONFIG_KEXEC_FILE +static inline void ima_add_kexec_buffer(struct kimage *image) +{ +} +#endif + #endif /* CONFIG_IMA */ #ifdef CONFIG_IMA_APPRAISE diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 0e90d1446cb0..75c1b8d67a72 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -248,6 +249,9 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, } } + /* IMA needs to pass the measurement list to the next kernel. */ + ima_add_kexec_buffer(image); + /* Call arch image load handlers */ ldata = arch_kexec_kernel_image_load(image); diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index db25f54a04fe..0334001055d7 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -102,6 +102,11 @@ struct ima_queue_entry { }; extern struct list_head ima_measurements; /* list of all measurements */ +#ifdef CONFIG_KEXEC_FILE +extern void *kexec_buffer; +extern size_t kexec_buffer_size; +#endif + /* Internal IMA function definitions */ int ima_init(void); int ima_fs_init(void); diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 32912bd54ead..a1924d0f3b2b 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "ima.h" @@ -104,6 +105,29 @@ void __init ima_load_x509(void) } #endif +#ifdef CONFIG_KEXEC_FILE +static void ima_load_kexec_buffer(void) +{ + int rc; + + /* Fetch the buffer from the previous kernel, if any. */ + rc = kexec_get_handover_buffer(&kexec_buffer, &kexec_buffer_size); + if (rc == 0) { + /* Demonstrate that buffer handover works. */ + pr_err("kexec buffer contents: %s\n", (char *) kexec_buffer); + pr_err("kexec buffer contents after update: %s\n", + (char *) kexec_buffer + 4 * PAGE_SIZE + 10); + + kexec_free_handover_buffer(); + } else if (rc == -ENOENT) + pr_debug("No kexec buffer from the previous kernel.\n"); + else + pr_debug("Error restoring kexec buffer: %d\n", rc); +} +#else +static void ima_load_kexec_buffer(void) { } +#endif + int __init ima_init(void) { u8 pcr_i[TPM_DIGEST_SIZE]; @@ -134,5 +158,7 @@ int __init ima_init(void) ima_init_policy(); + ima_load_kexec_buffer(); + return ima_fs_init(); } diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index febd12ed9b55..e9ac260534b6 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -15,6 +15,8 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include +#include #include "ima.h" #include "ima_template_lib.h" @@ -182,6 +184,89 @@ static int template_desc_init_fields(const char *template_fmt, return 0; } +#ifdef CONFIG_KEXEC_FILE +void *kexec_buffer; +size_t kexec_buffer_size; + +/* Physical address of the measurement buffer in the next kernel. */ +unsigned long kexec_buffer_load_addr; + +/* + * Called during reboot. IMA can add here new events that were generated after + * the kexec image was loaded. + */ +static int ima_update_kexec_buffer(struct notifier_block *self, + unsigned long action, void *data) +{ + int ret; + + if (!kexec_in_progress) + return NOTIFY_OK; + + /* + * Add content deep in the buffer to show that we can update + * all of it. + */ + strcpy(kexec_buffer + 4 * PAGE_SIZE + 10, + "Updated kexec buffer contents."); + + ret = kexec_update_segment(kexec_buffer, kexec_buffer_size, + kexec_buffer_load_addr, kexec_buffer_size); + if (ret) + pr_err("Error updating kexec buffer: %d\n", ret); + + return NOTIFY_OK; +} + +struct notifier_block update_buffer_nb = { + .notifier_call = ima_update_kexec_buffer, +}; + +/* + * Called during kexec_file_load so that IMA can add a segment to the kexec + * image with the measurement event log for the next kernel. + */ +void ima_add_kexec_buffer(struct kimage *image) +{ + /* Ask not to checksum the segment, we may have to update it later. */ + struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE, + .buf_min = 0, .buf_max = ULONG_MAX, + .top_down = true, .skip_checksum = true }; + bool first_kexec_load = kexec_buffer_load_addr == 0; + int ret; + + if (!kexec_can_hand_over_buffer()) + return; + + if (!first_kexec_load) + kfree(kexec_buffer); + + /* Create a relatively big buffer, for testing. */ + kexec_buffer_size = kbuf.bufsz = kbuf.memsz = 5 * PAGE_SIZE; + kexec_buffer = kbuf.buffer = kzalloc(kexec_buffer_size, GFP_KERNEL); + if (!kexec_buffer) { + pr_err("Not enough memory for the kexec measurement buffer.\n"); + return; + } + + /* Add some content for demonstration purposes. */ + strcpy(kexec_buffer, "Buffer contents at kexec load time."); + + ret = kexec_add_handover_buffer(&kbuf); + if (ret) { + pr_err("Error passing over kexec measurement buffer.\n"); + return; + } + kexec_buffer_load_addr = kbuf.mem; + + if (first_kexec_load) + register_reboot_notifier(&update_buffer_nb); + + pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", + kexec_buffer_load_addr); +} +#endif /* CONFIG_KEXEC_FILE */ + struct ima_template_desc *ima_template_desc_current(void) { if (!ima_template)