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Wed, 4 Oct 2023 22:15:10 +0000 (UTC) Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by relay.mimecast.com with ESMTP id us-mta-623-H3L7Jn2EMvSjJ08kz83m1g-1; Wed, 04 Oct 2023 18:15:09 -0400 X-MC-Unique: H3L7Jn2EMvSjJ08kz83m1g-1 Received: by linux.microsoft.com (Postfix, from userid 1052) id 7C6A520B74CC; Wed, 4 Oct 2023 15:09:50 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7C6A520B74CC From: Fan Wu To: corbet@lwn.net, zohar@linux.ibm.com, jmorris@namei.org, serge@hallyn.com, tytso@mit.edu, ebiggers@kernel.org, axboe@kernel.dk, agk@redhat.com, snitzer@kernel.org, eparis@redhat.com, paul@paul-moore.com Date: Wed, 4 Oct 2023 15:09:33 -0700 Message-Id: <1696457386-3010-7-git-send-email-wufan@linux.microsoft.com> In-Reply-To: <1696457386-3010-1-git-send-email-wufan@linux.microsoft.com> References: <1696457386-3010-1-git-send-email-wufan@linux.microsoft.com> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Subject: [dm-devel] [RFC PATCH v11 06/19] security: add new securityfs delete function X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dm-devel@redhat.com, linux-doc@vger.kernel.org, roberto.sassu@huawei.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, audit@vger.kernel.org, linux-fscrypt@vger.kernel.org, Fan Wu , linux-integrity@vger.kernel.org MIME-Version: 1.0 Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: linux.microsoft.com When deleting a directory in the security file system, the existing securityfs_remove requires the directory to be empty, otherwise it will do nothing. This leads to a potential risk that the security file system might be in an unclean state when the intentded deletion did not happen. This commit introduces a new function securityfs_recursive_remove to recursively delete a directory without leaving an unclean state. Co-developed-by: Christian Brauner (Microsoft) Signed-off-by: Fan Wu --- v1-v8: + Not present v9: + Introduced v10: + No changes v11: + Fix code style issues --- include/linux/security.h | 1 + security/inode.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/include/linux/security.h b/include/linux/security.h index 5f16eecde00b..8fa3bab9fa10 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1985,6 +1985,7 @@ struct dentry *securityfs_create_symlink(const char *name, const char *target, const struct inode_operations *iops); extern void securityfs_remove(struct dentry *dentry); +extern void securityfs_recursive_remove(struct dentry *dentry); #else /* CONFIG_SECURITYFS */ diff --git a/security/inode.c b/security/inode.c index 3aa75fffa8c9..e0585c2946c5 100644 --- a/security/inode.c +++ b/security/inode.c @@ -313,6 +313,31 @@ void securityfs_remove(struct dentry *dentry) } EXPORT_SYMBOL_GPL(securityfs_remove); +static void remove_one(struct dentry *victim) +{ + simple_release_fs(&mount, &mount_count); +} + +/** + * securityfs_recursive_remove - recursively removes a file or directory + * + * @dentry: a pointer to a the dentry of the file or directory to be removed. + * + * This function recursively removes a file or directory in securityfs that was + * previously created with a call to another securityfs function (like + * securityfs_create_file() or variants thereof.) + */ +void securityfs_recursive_remove(struct dentry *dentry) +{ + if (IS_ERR_OR_NULL(dentry)) + return; + + simple_pin_fs(&fs_type, &mount, &mount_count); + simple_recursive_removal(dentry, remove_one); + simple_release_fs(&mount, &mount_count); +} +EXPORT_SYMBOL_GPL(securityfs_recursive_remove); + #ifdef CONFIG_SECURITY static struct dentry *lsm_dentry; static ssize_t lsm_read(struct file *filp, char __user *buf, size_t count,