From patchwork Thu Dec 14 17:08:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13493430 X-Patchwork-Delegate: paul@paul-moore.com Received: from frasgout13.his.huawei.com (frasgout13.his.huawei.com [14.137.139.46]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF461126; Thu, 14 Dec 2023 09:13:18 -0800 (PST) Received: from mail.maildlp.com (unknown [172.18.186.29]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4SrdqR0p7nz9xrpf; Fri, 15 Dec 2023 00:59:15 +0800 (CST) Received: from mail02.huawei.com (unknown [7.182.16.27]) by mail.maildlp.com (Postfix) with ESMTP id D4A7914074C; Fri, 15 Dec 2023 01:13:06 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwAHuGFtN3tlDa2DAg--.53313S5; Thu, 14 Dec 2023 18:13:06 +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, shuah@kernel.org, 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, linux-kselftest@vger.kernel.org, Roberto Sassu Subject: [PATCH v8 13/24] security: Introduce file_release hook Date: Thu, 14 Dec 2023 18:08:23 +0100 Message-Id: <20231214170834.3324559-14-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231214170834.3324559-1-roberto.sassu@huaweicloud.com> References: <20231214170834.3324559-1-roberto.sassu@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: GxC2BwAHuGFtN3tlDa2DAg--.53313S5 X-Coremail-Antispam: 1UD129KBjvJXoWxAFW7CF1xAr4UKrykJF4ktFb_yoW5ur45pr Z8t3WUGFW5GF12grn7Aanrua4fK393KryDWrZ5W345tF1kJr95Kan8CryUCFs8JrWkJr10 qw12grW3Gr4DArJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBab4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUWw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2 WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkE bVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCF04k20xvY0x 0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E 7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vIr41lIxAIcV C0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI42IY 6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aV CY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07UQZ2-UUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQALBF1jj5envAAEs3 From: Roberto Sassu In preparation for moving IMA and EVM to the LSM infrastructure, introduce the file_release 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 de4a2915bfd4..c72dc75f2bd3 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -385,6 +385,7 @@ static void __fput(struct file *file) eventpoll_release(file); locks_remove_file(file); + security_file_release(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 e2b45fee94e2..175ca00a6b1d 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_release, 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 c360458920b1..4c3585e3dcb4 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_release(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_release(struct file *file) +{ } + static inline void security_file_free(struct file *file) { } diff --git a/security/security.c b/security/security.c index fe6a160afc35..9aa072ca5a19 100644 --- a/security/security.c +++ b/security/security.c @@ -2724,6 +2724,17 @@ int security_file_alloc(struct file *file) return rc; } +/** + * security_file_release() - Perform actions before releasing the file ref + * @file: the file + * + * Perform actions before releasing the last reference to a file. + */ +void security_file_release(struct file *file) +{ + call_void_hook(file_release, file); +} + /** * security_file_free() - Free a file's LSM blob * @file: the file