From patchwork Sat Mar 16 03:35:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fan Wu X-Patchwork-Id: 13594252 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5BCCC566D; Sat, 16 Mar 2024 03:35:56 +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=1710560158; cv=none; b=iocuIvpi7EdGrlabHrfBlDYaIzN7tGE8o6y58HYl97hCFbF9akky39UgzcZbUMmIlS5k1dXiYcXdAET91VwIl/SjSMskNRJhe7TlUNsFf1cuVKFbhOZ7WxafQ0yBNlMQY2cTsRUsoVZxGIrniHUkUm0LrgnZlzI1MS+vnk15WZY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710560158; c=relaxed/simple; bh=h2TsFDtKUmvVYqz3LZafSvm9/uITgSQXr06rA0VNW2g=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=TS5O32mJo3kDsK//pug0cS1swAf2K2ifWGTERLNCW1AwbgxovmK3C+2IV4MKzzwU6Xy4koELa/QO0JV7S62DWXwmvX5d88Xw4nqHUprQ1cKxhC7blTidrWE4GQ5MWJPaBw0J5OB9bvBrFVTvCdEagQph2pm2WCTqkNj8MYsWC1E= 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=AbGw6VfF; 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="AbGw6VfF" Received: by linux.microsoft.com (Postfix, from userid 1052) id 9319A20B74CD; Fri, 15 Mar 2024 20:35:53 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 9319A20B74CD DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1710560153; bh=KoMFZSyeRwf0zohBKcDt7DanemgxhgRO3TjK5eTmxY4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AbGw6VfFzmFXZ6tJljnNn7HCZ8MbSv/D7t/E8D6H90fOw5C53a5N8zkhDPTECZcqa OEDkumKnDOHDIY0H1lSd2bFT3NATMCYzMPxFas9pA1y5UuQX/ZIq6KYMFt2RHWPDYf WjiTsp0m8c9E1R9jOYr6G4BgBukQw/CVwAVnJm00= 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: [RFC PATCH v15 07/21] security: add new securityfs delete function Date: Fri, 15 Mar 2024 20:35:37 -0700 Message-Id: <1710560151-28904-8-git-send-email-wufan@linux.microsoft.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1710560151-28904-1-git-send-email-wufan@linux.microsoft.com> References: <1710560151-28904-1-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 --- 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,