From patchwork Thu Sep 15 00:54:50 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: 670184 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3sZKs51C6gz9s9Y for ; Thu, 15 Sep 2016 11:02:49 +1000 (AEST) Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3sZKs50NxqzDsd9 for ; Thu, 15 Sep 2016 11:02:49 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3sZKhS3zQqzDsWy for ; Thu, 15 Sep 2016 10:55:20 +1000 (AEST) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8F0qc7I044692 for ; Wed, 14 Sep 2016 20:55:19 -0400 Received: from e24smtp04.br.ibm.com (e24smtp04.br.ibm.com [32.104.18.25]) by mx0a-001b2d01.pphosted.com with ESMTP id 25exqrphy3-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 14 Sep 2016 20:55:18 -0400 Received: from localhost by e24smtp04.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 14 Sep 2016 21:55:09 -0300 X-IBM-Helo: d24dlp02.br.ibm.com X-IBM-MailFrom: bauerman@linux.vnet.ibm.com X-IBM-RcptTo: linuxppc-dev@lists.ozlabs.org Received: from d24relay01.br.ibm.com (d24relay01.br.ibm.com [9.8.31.16]) by d24dlp02.br.ibm.com (Postfix) with ESMTP id 61BFF1DC006D for ; Wed, 14 Sep 2016 20:55:09 -0400 (EDT) Received: from d24av02.br.ibm.com (d24av02.br.ibm.com [9.8.31.93]) by d24relay01.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u8F0t9ao4481094 for ; Wed, 14 Sep 2016 21:55:09 -0300 Received: from d24av02.br.ibm.com (localhost [127.0.0.1]) by d24av02.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u8F0t81n005601 for ; Wed, 14 Sep 2016 21:55:09 -0300 Received: from hactar.ibm.com ([9.78.147.6]) by d24av02.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u8F0ssCC005187; Wed, 14 Sep 2016 21:55:06 -0300 From: Thiago Jung Bauermann To: kexec@lists.infradead.org Subject: [PATCH v5 5/5] IMA: Demonstration code for kexec buffer passing. Date: Wed, 14 Sep 2016 21:54:50 -0300 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1473900890-1476-1-git-send-email-bauerman@linux.vnet.ibm.com> References: <1473900890-1476-1-git-send-email-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16091500-0028-0000-0000-00000143E24E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16091500-0029-0000-0000-0000141570DD Message-Id: <1473900890-1476-6-git-send-email-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-09-14_11:, , 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=8.0.1-1609020000 definitions=main-1609150010 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stewart Smith , Stephen Rothwell , "H. Peter Anvin" , Baoquan He , linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, Thiago Jung Bauermann , Ingo Molnar , Eric Biederman , linux-ima-devel@lists.sourceforge.net, Andrew Morton , Mimi Zohar , Dave Young , Thomas Gleixner , Vivek Goyal Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 Signed-off-by: Thiago Jung Bauermann --- 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 fbcec07bb3f5..0146619479a6 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -252,6 +253,9 @@ 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..92ea3afd9a1f 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 }; + 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)