From patchwork Thu Dec 14 17:08:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 13493431 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 B90191AD; Thu, 14 Dec 2023 09:13:32 -0800 (PST) Received: from mail.maildlp.com (unknown [172.18.186.51]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4Srdqg5pTGz9y7Z8; Fri, 15 Dec 2023 00:59:27 +0800 (CST) Received: from mail02.huawei.com (unknown [7.182.16.27]) by mail.maildlp.com (Postfix) with ESMTP id 893DC14064E; Fri, 15 Dec 2023 01:13:19 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwAHuGFtN3tlDa2DAg--.53313S6; Thu, 14 Dec 2023 18:13:18 +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 14/24] security: Introduce path_post_mknod hook Date: Thu, 14 Dec 2023 18:08:24 +0100 Message-Id: <20231214170834.3324559-15-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--.53313S6 X-Coremail-Antispam: 1UD129KBjvJXoWxWr43Xr48uryrGF43Xr1rCrg_yoWrXrykpa 1rtFnxGr4rGFy3Wr1kAFsrCaySvrW5u3y7JFZ0gwnIyFnxtrnYqF4S9r1Ykr9xGrWUKryI qa17tr43Gr4Utr7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBvb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUAV Cq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0 rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267 AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E 14v26r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrV C2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE 7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCF04k20x vY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I 3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_WrylIxkGc2Ij64vIr41lIx AIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJwCI 42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z2 80aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x07UdfHUUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQALBF1jj5envAAGs1 From: Roberto Sassu In preparation for moving IMA and EVM to the LSM infrastructure, introduce the path_post_mknod hook. IMA-appraisal requires all existing files in policy to have a file hash/signature stored in security.ima. An exception is made for empty files created by mknod, by tagging them as new files. LSMs could also take some action after files are created. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu Acked-by: Casey Schaufler Reviewed-by: Mimi Zohar --- fs/namei.c | 5 +++++ include/linux/lsm_hook_defs.h | 2 ++ include/linux/security.h | 5 +++++ security/security.c | 14 ++++++++++++++ 4 files changed, 26 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index fb93d3e13df6..b7f433720b1e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4047,6 +4047,11 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode, dentry, mode, 0); break; } + + if (error) + goto out2; + + security_path_post_mknod(idmap, dentry); out2: done_path_create(&path, dentry); if (retry_estale(error, lookup_flags)) { diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 175ca00a6b1d..ee5ab180a312 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -94,6 +94,8 @@ LSM_HOOK(int, 0, path_mkdir, const struct path *dir, struct dentry *dentry, LSM_HOOK(int, 0, path_rmdir, const struct path *dir, struct dentry *dentry) LSM_HOOK(int, 0, path_mknod, const struct path *dir, struct dentry *dentry, umode_t mode, unsigned int dev) +LSM_HOOK(void, LSM_RET_VOID, path_post_mknod, struct mnt_idmap *idmap, + struct dentry *dentry) LSM_HOOK(int, 0, path_truncate, const struct path *path) LSM_HOOK(int, 0, path_symlink, const struct path *dir, struct dentry *dentry, const char *old_name) diff --git a/include/linux/security.h b/include/linux/security.h index 4c3585e3dcb4..5f595135c8f2 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1884,6 +1884,7 @@ int security_path_mkdir(const struct path *dir, struct dentry *dentry, umode_t m int security_path_rmdir(const struct path *dir, struct dentry *dentry); int security_path_mknod(const struct path *dir, struct dentry *dentry, umode_t mode, unsigned int dev); +void security_path_post_mknod(struct mnt_idmap *idmap, struct dentry *dentry); int security_path_truncate(const struct path *path); int security_path_symlink(const struct path *dir, struct dentry *dentry, const char *old_name); @@ -1918,6 +1919,10 @@ static inline int security_path_mknod(const struct path *dir, struct dentry *den return 0; } +static inline void security_path_post_mknod(struct mnt_idmap *idmap, + struct dentry *dentry) +{ } + static inline int security_path_truncate(const struct path *path) { return 0; diff --git a/security/security.c b/security/security.c index 9aa072ca5a19..b0203c488d17 100644 --- a/security/security.c +++ b/security/security.c @@ -1800,6 +1800,20 @@ int security_path_mknod(const struct path *dir, struct dentry *dentry, } EXPORT_SYMBOL(security_path_mknod); +/** + * security_path_post_mknod() - Update inode security field after file creation + * @idmap: idmap of the mount + * @dentry: new file + * + * Update inode security field after a file has been created. + */ +void security_path_post_mknod(struct mnt_idmap *idmap, struct dentry *dentry) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(path_post_mknod, idmap, dentry); +} + /** * security_path_mkdir() - Check if creating a new directory is allowed * @dir: parent directory