From patchwork Thu Mar 28 20:17:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fan Wu X-Patchwork-Id: 13609527 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B3EA413A40F; Thu, 28 Mar 2024 20:17:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711657055; cv=none; b=hxDg7Fm2Vxtp5xwFqmtzO3ppWZW+uFpMfivfRbNzIbF9uwRwslACUXmTLGt2tjtTwWs1rfR/X3EUUk8O6bQynTJcNWnNendnfXOVhN29srcbdJL0KJg811Hi5OyGUd8RjVRj3HDQj6UoC3Cpxv9B4qpV4x4TUH5ci2uCPD3hA1w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711657055; c=relaxed/simple; bh=ERtVd4c+JTIOe6n+GNIMs+hsdgt4u+Qnlx/zLKgYdg4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=EXxN4UQuXWXp3CIwnvkqJsIy4YUEPB0htivM7OFQgKVSU8FBvlvI8scAqGOt3fqH9xYlJsjBy3hAT0y1CDcCRMbJVMe7B7u9WFLnw5+5gTAEfx1T7/0pl22Ty5ZnTGWhXT56fFN7iW94zfDoAwKuJ6rtlxzGX2KnSXpQih/KwTs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=RJFz0xO3; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="RJFz0xO3" Received: by linux.microsoft.com (Postfix, from userid 1052) id C0DCE20E6F25; Thu, 28 Mar 2024 13:17:28 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C0DCE20E6F25 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1711657048; bh=/WSEDQnY3jfJtaJ7pIJVTHdQDsHKQKIwG6cPA6bswW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RJFz0xO3799FtV64Fbre1NHLaTFroEek5MySWwH9cB/KNkrd0exsjaaNRUjAXfIOb 6Bua2oxhn5/hZw8TDz9rymv3YhKbuvlw3umChV8ecpnBo7rh3Eq111LdtnaSMj6WxT cKatK9/Z8/CLVFEw4waA0d6eRmSOvKxnKk3vbtkI= 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 Cc: linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, fsverity@lists.linux.dev, linux-block@vger.kernel.org, dm-devel@lists.linux.dev, audit@vger.kernel.org, linux-kernel@vger.kernel.org, Fan Wu Subject: [PATCH v16 07/20] security: add new securityfs delete function Date: Thu, 28 Mar 2024 13:17:14 -0700 Message-Id: <1711657047-10526-8-git-send-email-wufan@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1711657047-10526-1-git-send-email-wufan@linux.microsoft.com> References: <1711657047-10526-1-git-send-email-wufan@linux.microsoft.com> Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: 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 intended 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 v12: + No changes v13: + No changes v14: + No changes v15: + No changes v16: + No changes --- 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 14fff542f2e3..f35af7b6cfba 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -2089,6 +2089,7 @@ 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 9e7cde913667..f21847badb7d 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,