From patchwork Sat Nov 21 00:50:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11923041 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 89DB6C63798 for ; Sat, 21 Nov 2020 00:51:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3658F23A65 for ; Sat, 21 Nov 2020 00:51:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="HDfVcfah" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728593AbgKUAvF (ORCPT ); Fri, 20 Nov 2020 19:51:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727900AbgKUAvA (ORCPT ); Fri, 20 Nov 2020 19:51:00 -0500 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D58CC061A04 for ; Fri, 20 Nov 2020 16:50:58 -0800 (PST) Received: by mail-wr1-x442.google.com with SMTP id p1so12636619wrf.12 for ; Fri, 20 Nov 2020 16:50:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=4EcEA95lNa5ZZ+4yTLKOmHZRpqe2owrp9tTkgwACEiM=; b=HDfVcfahM3bKl9+qUQ17zfP7VPqPF47VMw+BHus3Ay4VZMn3CaP64kl4ysBf8B662Z 8iy2knqgDfzfRBSuxTRSuVI/mM9QU6Xl3uvF+LmivdARc+EhYceK73AoEr5+4YBtgdwx H6MZ1Xw9f4RCyLGtwXbNlRLg4+6a4ugdGEerA= 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:mime-version :content-transfer-encoding; bh=4EcEA95lNa5ZZ+4yTLKOmHZRpqe2owrp9tTkgwACEiM=; b=LFaJ06DjD764HUkbErHwz9DRrdIjdmj8KWkglYInnTljfNA9RSBvWfdpzXlWapXnNp eJMdYPUK9B99S645bIoq1mdQoVS0+auDB8WkOGZeh3os1iG5vxv4xOZVGxw0m4J642+n VoyMoxUxEPDkZ1kAkL/4Mfq0LSOgvXq28aO6JRYxajr6Zrg3z7wrw/N1g+n7aW7ZtKha tgr+ehLCeaQG5JKU8rCyRuCygE6pSW/KewS0wZOzVLq0y72X0Wk88bpq0+Q5sPklIzA9 6yQIQl8K38pvUj5uUTEB1jMr50SLskJYYvOWE3yCzs2tvobIxy14U2v92ML98bD8klQF wTpg== X-Gm-Message-State: AOAM531Wu+QCTDSSNR4Ao9DFCqUs7DcKtPt/R8Le9eq3e1rzvQJzvX/0 BjTw3BxjVWmcs7hpsr0MO2RVFMfrLJet7q/8 X-Google-Smtp-Source: ABdhPJwn2Ze2G+n7GEIgV6IFe/lQ3oFyWVfyjqDt0housibEsSKQxsoyQ5onAdYaytbYDxL5VwbWIA== X-Received: by 2002:adf:ead1:: with SMTP id o17mr18872821wrn.396.1605919856713; Fri, 20 Nov 2020 16:50:56 -0800 (PST) Received: from kpsingh.c.googlers.com.com (203.75.199.104.bc.googleusercontent.com. [104.199.75.203]) by smtp.gmail.com with ESMTPSA id s8sm7133607wrn.33.2020.11.20.16.50.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Nov 2020 16:50:56 -0800 (PST) From: KP Singh To: James Morris , linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Florent Revest , Brendan Jackman , Mimi Zohar Subject: [PATCH bpf-next v2 1/3] ima: Implement ima_inode_hash Date: Sat, 21 Nov 2020 00:50:52 +0000 Message-Id: <20201121005054.3467947-1-kpsingh@chromium.org> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog MIME-Version: 1.0 Precedence: bulk List-ID: From: KP Singh This is in preparation to add a helper for BPF LSM programs to use IMA hashes when attached to LSM hooks. There are LSM hooks like inode_unlink which do not have a struct file * argument and cannot use the existing ima_file_hash API. An inode based API is, therefore, useful in LSM based detections like an executable trying to delete itself which rely on the inode_unlink LSM hook. Moreover, the ima_file_hash function does nothing with the struct file pointer apart from calling file_inode on it and converting it to an inode. Signed-off-by: KP Singh Acked-by: Yonghong Song --- include/linux/ima.h | 6 +++ security/integrity/ima/ima_main.c | 78 +++++++++++++++++++++---------- 2 files changed, 60 insertions(+), 24 deletions(-) diff --git a/include/linux/ima.h b/include/linux/ima.h index 8fa7bcfb2da2..7233a2751754 100644 --- a/include/linux/ima.h +++ b/include/linux/ima.h @@ -29,6 +29,7 @@ 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 int ima_file_hash(struct file *file, char *buf, size_t buf_size); +extern int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size); extern void ima_kexec_cmdline(int kernel_fd, const void *buf, int size); #ifdef CONFIG_IMA_KEXEC @@ -115,6 +116,11 @@ static inline int ima_file_hash(struct file *file, char *buf, size_t buf_size) return -EOPNOTSUPP; } +static inline int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) +{ + return -EOPNOTSUPP; +} + static inline void ima_kexec_cmdline(int kernel_fd, const void *buf, int size) {} #endif /* CONFIG_IMA */ diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 2d1af8899cab..cb2deaa188e7 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -501,37 +501,14 @@ int ima_file_check(struct file *file, int mask) } EXPORT_SYMBOL_GPL(ima_file_check); -/** - * ima_file_hash - return the stored measurement if a file has been hashed and - * is in the iint cache. - * @file: pointer to the file - * @buf: buffer in which to store the hash - * @buf_size: length of the buffer - * - * On success, return the hash algorithm (as defined in the enum hash_algo). - * If buf is not NULL, this function also outputs the hash into buf. - * If the hash is larger than buf_size, then only buf_size bytes will be copied. - * It generally just makes sense to pass a buffer capable of holding the largest - * possible hash: IMA_MAX_DIGEST_SIZE. - * The file hash returned is based on the entire file, including the appended - * signature. - * - * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. - * If the parameters are incorrect, return -EINVAL. - */ -int ima_file_hash(struct file *file, char *buf, size_t buf_size) +static int __ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) { - struct inode *inode; struct integrity_iint_cache *iint; int hash_algo; - if (!file) - return -EINVAL; - if (!ima_policy_flag) return -EOPNOTSUPP; - inode = file_inode(file); iint = integrity_iint_find(inode); if (!iint) return -EOPNOTSUPP; @@ -558,8 +535,61 @@ int ima_file_hash(struct file *file, char *buf, size_t buf_size) return hash_algo; } + +/** + * ima_file_hash - return the stored measurement if a file has been hashed and + * is in the iint cache. + * @file: pointer to the file + * @buf: buffer in which to store the hash + * @buf_size: length of the buffer + * + * On success, return the hash algorithm (as defined in the enum hash_algo). + * If buf is not NULL, this function also outputs the hash into buf. + * If the hash is larger than buf_size, then only buf_size bytes will be copied. + * It generally just makes sense to pass a buffer capable of holding the largest + * possible hash: IMA_MAX_DIGEST_SIZE. + * The file hash returned is based on the entire file, including the appended + * signature. + * + * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. + * If the parameters are incorrect, return -EINVAL. + */ +int ima_file_hash(struct file *file, char *buf, size_t buf_size) +{ + if (!file) + return -EINVAL; + + return __ima_inode_hash(file_inode(file), buf, buf_size); +} EXPORT_SYMBOL_GPL(ima_file_hash); +/** + * ima_inode_hash - return the stored measurement if the inode has been hashed + * and is in the iint cache. + * @inode: pointer to the inode + * @buf: buffer in which to store the hash + * @buf_size: length of the buffer + * + * On success, return the hash algorithm (as defined in the enum hash_algo). + * If buf is not NULL, this function also outputs the hash into buf. + * If the hash is larger than buf_size, then only buf_size bytes will be copied. + * It generally just makes sense to pass a buffer capable of holding the largest + * possible hash: IMA_MAX_DIGEST_SIZE. + * The hash returned is based on the entire contents, including the appended + * signature. + * + * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP. + * If the parameters are incorrect, return -EINVAL. + */ +int ima_inode_hash(struct inode *inode, char *buf, size_t buf_size) +{ + if (!inode) + return -EINVAL; + + return __ima_inode_hash(inode, buf, buf_size); +} +EXPORT_SYMBOL_GPL(ima_inode_hash); + /** * ima_post_create_tmpfile - mark newly created tmpfile as new * @file : newly created tmpfile