From patchwork Fri Oct 27 08:35:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13438270 X-Patchwork-Delegate: paul@paul-moore.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30F39C25B6E for ; Fri, 27 Oct 2023 08:41:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235197AbjJ0IlM (ORCPT ); Fri, 27 Oct 2023 04:41:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235194AbjJ0Ikp (ORCPT ); Fri, 27 Oct 2023 04:40:45 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 212A71B1; Fri, 27 Oct 2023 01:40:22 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.227]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4SGwgW4XnLz9xxnN; Fri, 27 Oct 2023 16:24:23 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwCX8JGqdjtlDvIBAw--.29710S15; Fri, 27 Oct 2023 09:39:54 +0100 (CET) From: Roberto Sassu To: viro@zeniv.linux.org.uk, brauner@kernel.org, chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de, kolga@netapp.com, Dai.Ngo@oracle.com, tom@talpey.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, dhowells@redhat.com, jarkko@kernel.org, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com, mic@digikod.net Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, selinux@vger.kernel.org, Roberto Sassu Subject: [PATCH v4 13/23] security: Introduce file_pre_free_security hook Date: Fri, 27 Oct 2023 10:35:48 +0200 Message-Id: <20231027083558.484911-14-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231027083558.484911-1-roberto.sassu@huaweicloud.com> References: <20231027083558.484911-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: LxC2BwCX8JGqdjtlDvIBAw--.29710S15 X-Coremail-Antispam: 1UD129KBjvJXoWxAFW7CF1xAr4Utw4xJFWDArb_yoW5uF1fpr Z8t3W5GFW5GF12grn3Aanrua4ft393KrWUWrZ5u34rtFnrJryvgFZ8CFy5CF15JrWkJry0 qw12grW3Gr4DArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBvb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E 14v26r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrV C2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE 7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCF04k20x vY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I 3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vIr41lIx AIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI 42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z2 80aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07UZo7tUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAgADBF1jj5GTnwABso X-CFilter-Loop: Reflected Precedence: bulk List-ID: From: Roberto Sassu In preparation for moving IMA and EVM to the LSM infrastructure, introduce the file_pre_free_security hook. IMA calculates at file close the new digest of the file content and writes it to security.ima, so that appraisal at next file access succeeds. LSMs could also take some action before the last reference of a file is released. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu --- fs/file_table.c | 1 + include/linux/lsm_hook_defs.h | 1 + include/linux/security.h | 4 ++++ security/security.c | 11 +++++++++++ 4 files changed, 17 insertions(+) diff --git a/fs/file_table.c b/fs/file_table.c index ee21b3da9d08..ca36679adaa4 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -375,6 +375,7 @@ static void __fput(struct file *file) eventpoll_release(file); locks_remove_file(file); + security_file_pre_free(file); ima_file_free(file); if (unlikely(file->f_flags & FASYNC)) { if (file->f_op->fasync) diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index cab9c1265f4e..21da4cadcad3 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -173,6 +173,7 @@ LSM_HOOK(int, 0, kernfs_init_security, struct kernfs_node *kn_dir, struct kernfs_node *kn) LSM_HOOK(int, 0, file_permission, struct file *file, int mask) LSM_HOOK(int, 0, file_alloc_security, struct file *file) +LSM_HOOK(void, LSM_RET_VOID, file_pre_free_security, struct file *file) LSM_HOOK(void, LSM_RET_VOID, file_free_security, struct file *file) LSM_HOOK(int, 0, file_ioctl, struct file *file, unsigned int cmd, unsigned long arg) diff --git a/include/linux/security.h b/include/linux/security.h index e0812da7f24d..47c3502d8600 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -395,6 +395,7 @@ int security_kernfs_init_security(struct kernfs_node *kn_dir, struct kernfs_node *kn); int security_file_permission(struct file *file, int mask); int security_file_alloc(struct file *file); +void security_file_pre_free(struct file *file); void security_file_free(struct file *file); int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg); int security_mmap_file(struct file *file, unsigned long prot, @@ -1006,6 +1007,9 @@ static inline int security_file_alloc(struct file *file) return 0; } +static inline void security_file_pre_free(struct file *file) +{ } + static inline void security_file_free(struct file *file) { } diff --git a/security/security.c b/security/security.c index d24a8f92d641..e3586a37d62c 100644 --- a/security/security.c +++ b/security/security.c @@ -2717,6 +2717,17 @@ int security_file_alloc(struct file *file) return rc; } +/** + * security_file_pre_free() - Perform actions before releasing the file ref + * @file: the file + * + * Perform actions before releasing the last reference to a file. + */ +void security_file_pre_free(struct file *file) +{ + call_void_hook(file_pre_free_security, file); +} + /** * security_file_free() - Free a file's LSM blob * @file: the file