From patchwork Mon Apr 29 21:47:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prakhar Srivastava X-Patchwork-Id: 10922533 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0B81F92A for ; Mon, 29 Apr 2019 21:48:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EE4792580E for ; Mon, 29 Apr 2019 21:48:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E1EC7289B6; Mon, 29 Apr 2019 21:48:16 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI,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 476132580E for ; Mon, 29 Apr 2019 21:48:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729534AbfD2Vrx (ORCPT ); Mon, 29 Apr 2019 17:47:53 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:33117 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729341AbfD2Vrw (ORCPT ); Mon, 29 Apr 2019 17:47:52 -0400 Received: by mail-pf1-f194.google.com with SMTP id z28so684069pfk.0; Mon, 29 Apr 2019 14:47:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=tiAA+ScOqrpgokB/bI2A0TI/jwnpVeqj9LdR6JH5rDY=; b=QO+jToI9AspTW//i/bLjwWVqcRVIcXqgLo6xASBAZLLLLcFmer2JhKYttxWPUS5fmR 35RdRZUXW4IPlwPcRzdc0vbiiyPgRgGJL4Equ0dNPMdKlDFLzfBEs6N+THH9VEDMrRgF wLwYgiVyr1HHGqf+n/n9sufufg5Xq5nKac5PmTC4hiAbJcJq3LaGBopVuXuAAmsnWin8 jE0PrIn8kIBtoO/f/TuwGtA7DajxWZ69rOVbRhUYY1YNtDKB2TbgUTecoNVbSVJlEs03 GD+SFGu3vBvVqYQpRdyYzrvYqbgZAhLn2wbdmx2kdqr1PDVkSYCDJ073O2u4GQGUnzck vOqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=tiAA+ScOqrpgokB/bI2A0TI/jwnpVeqj9LdR6JH5rDY=; b=FeQx762VaLFsH4vyfsj9xKpz5svm1Z4UlzCF+uG7xC/yh9Hv9zatnmdgV9cMEDNjg6 DIZtaEwOLcER+RWJYtSYN/7YafyXq4O9FeYa0SeP3AOW4L2eyJxA8i2Kl3hQjIpbdRdB anAA1DoOYqHP+vJux8QE8Mqx0ov71qCC774aWptPGXd+Qpp/0zEouozWU77XgHoHy5Tq gBby2XFeEjTiiEJ+SAao5d/RWEnAksQTvwFKC1knRR0sr9zRePZ8Of7FZgDdN4Cc3CHI QHOin1907++jQR6TlX8xAEbaQGrcceU+Fhts4OKnadhKWJJsmThO96P/0CJ/nqpqWeci ofXQ== X-Gm-Message-State: APjAAAUmfieqMnkNI3/DnYtffN3Gomke1C3lEYc1FFPMEi6eTGp2lwX/ P6IdPvsPXQSGJvCEpW8ccIFuqlSgUYU= X-Google-Smtp-Source: APXvYqz4aE8Jf2gWOZfB26bgGisMVRY08iPh62yu86FZmHRZNA1Yc+0YNknkY8kW7xLjaUdxzzPP8w== X-Received: by 2002:a62:2a44:: with SMTP id q65mr33131002pfq.226.1556574471359; Mon, 29 Apr 2019 14:47:51 -0700 (PDT) Received: from prsriva-linux.corp.microsoft.com ([2001:4898:80e8:9:445d:9822:2ddb:fb8c]) by smtp.gmail.com with ESMTPSA id f66sm1941623pfg.55.2019.04.29.14.47.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 29 Apr 2019 14:47:50 -0700 (PDT) From: Prakhar Srivastava X-Google-Original-From: Prakhar Srivastava To: linux-integrity@vger.kernel.org, linux-secuirty-module@vger.kernel.org, linux-kernel@vger.kernel.org Cc: zohar@linux.ibm.com, ebiederm@xmission.com, vgoyal@redhat.com, nayna@linux.ibm.com, Prakhar Srivastava Subject: [PATCH v3 1/4] added a new ima policy func buffer_check, and ima hook to measure the buffer hash into ima Date: Mon, 29 Apr 2019 14:47:40 -0700 Message-Id: <20190429214743.4625-2-prsriva02@gmail.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190429214743.4625-1-prsriva02@gmail.com> References: <20190429214743.4625-1-prsriva02@gmail.com> MIME-Version: 1.0 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Prakhar Srivastava added a new ima policy func buffer_check, and ima hook to measure the buffer hash into ima logs. Signed-off-by: Prakhar Srivastava --- Documentation/ABI/testing/ima_policy | 1 + include/linux/ima.h | 5 ++ security/integrity/ima/ima.h | 1 + security/integrity/ima/ima_api.c | 1 + security/integrity/ima/ima_main.c | 89 ++++++++++++++++++++++++++++ security/integrity/ima/ima_policy.c | 8 +++ 6 files changed, 105 insertions(+) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 74c6702de74e..12cfe3ff2dea 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -29,6 +29,7 @@ Description: base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK] [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] + [BUFFER_CHECK] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value diff --git a/include/linux/ima.h b/include/linux/ima.h index dc12fbcf484c..f0abade74707 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -26,6 +26,8 @@ extern int ima_read_file(struct file *file, enum kernel_read_file_id id); 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); +extern void ima_buffer_check(const void *buff, int size, + const char *eventname); #ifdef CONFIG_IMA_KEXEC extern void ima_add_kexec_buffer(struct kimage *image); @@ -92,6 +94,9 @@ static inline void ima_post_path_mknod(struct dentry *dentry) return; } +static inline void ima_buffer_check(const void *buff, int size, + const char *eventname) +{} #endif /* CONFIG_IMA */ #ifndef CONFIG_IMA_KEXEC diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index d213e835c498..de70df132575 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -184,6 +184,7 @@ static inline unsigned long ima_hash_key(u8 *digest) hook(KEXEC_KERNEL_CHECK) \ hook(KEXEC_INITRAMFS_CHECK) \ hook(POLICY_CHECK) \ + hook(BUFFER_CHECK) \ hook(MAX_CHECK) #define __ima_hook_enumify(ENUM) ENUM, diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index c7505fb122d4..cb3f67b366f1 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -169,6 +169,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, * subj=, obj=, type=, func=, mask=, fsmagic= * subj,obj, and type: are LSM specific. * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK + * | BUFFER_CHECK * mask: contains the permission mask * fsmagic: hex value * diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 357edd140c09..3db3f3966ac7 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -576,6 +576,95 @@ int ima_load_data(enum kernel_load_data_id id) return 0; } +/* + * process_buffer_measurement - Measure the buffer passed to ima log. + * (Instead of using the file hash the buffer hash is used). + * @buff - The buffer that needs to be added to the log + * @size - size of buffer(in bytes) + * @eventname - this is eventname used for the various buffers + * that can be measured. + * + * The buffer passed is added to the ima logs. + * If the sig template is used, then the sig field contains the buffer. + * + * On success return 0. + * On error cases surface errors from ima calls. + */ +static int process_buffer_measurement(const void *buff, int size, + const char *eventname, const struct cred *cred, + u32 secid) +{ + int ret = -EINVAL; + struct ima_template_entry *entry = NULL; + struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; + struct ima_event_data event_data = {iint, NULL, NULL, + NULL, 0, NULL}; + struct { + struct ima_digest_data hdr; + char digest[IMA_MAX_DIGEST_SIZE]; + } hash; + int violation = 0; + int pcr = CONFIG_IMA_MEASURE_PCR_IDX; + + if (!buff || size == 0 || !eventname) + goto err_out; + + if (ima_get_action(NULL, cred, secid, 0, BUFFER_CHECK, &pcr) + != IMA_MEASURE) + goto err_out; + + memset(iint, 0, sizeof(*iint)); + memset(&hash, 0, sizeof(hash)); + + event_data.filename = eventname; + + iint->ima_hash = &hash.hdr; + iint->ima_hash->algo = ima_hash_algo; + iint->ima_hash->length = hash_digest_size[ima_hash_algo]; + + ret = ima_calc_buffer_hash(buff, size, iint->ima_hash); + if (ret < 0) + goto err_out; + + ret = ima_alloc_init_template(&event_data, &entry); + if (ret < 0) + goto err_out; + + ret = ima_store_template(entry, violation, NULL, + buff, pcr); + if (ret < 0) { + ima_free_template_entry(entry); + goto err_out; + } + + return 0; + +err_out: + pr_err("Error in adding buffer measure: %d\n", ret); + return ret; +} + +/** + * ima_buffer_check - based on policy, collect & store buffer measurement + * @buf: pointer to buffer + * @size: size of buffer + * @eventname: event name identifier + * + * Buffers can only be measured, not appraised. The buffer identifier + * is used as the measurement list entry name (eg. boot_cmdline). + */ +void ima_buffer_check(const void *buf, int size, const char *eventname) +{ + u32 secid; + + if (buf && size != 0 && eventname) { + security_task_getsecid(current, &secid); + process_buffer_measurement(buf, size, eventname, + current_cred(), secid); + } +} + + static int __init init_ima(void) { int error; diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index e0cc323f948f..b12551ed191c 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -291,6 +291,12 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, { int i; + // Incase of BUFFER_CHECK, Inode is NULL + if (!inode) { + if ((rule->flags & IMA_FUNC) && (rule->func == func)) + return true; + return false; + } if ((rule->flags & IMA_FUNC) && (rule->func != func && func != POST_SETATTR)) return false; @@ -869,6 +875,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) entry->func = KEXEC_INITRAMFS_CHECK; else if (strcmp(args[0].from, "POLICY_CHECK") == 0) entry->func = POLICY_CHECK; + else if (strcmp(args[0].from, "BUFFER_CHECK") == 0) + entry->func = BUFFER_CHECK; else result = -EINVAL; if (!result)