From patchwork Tue Sep 6 00:35:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sweet Tea Dorminy X-Patchwork-Id: 12966678 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5923C6FA86 for ; Tue, 6 Sep 2022 00:35:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229575AbiIFAfs (ORCPT ); Mon, 5 Sep 2022 20:35:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39480 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232204AbiIFAfq (ORCPT ); Mon, 5 Sep 2022 20:35:46 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8457267C97; Mon, 5 Sep 2022 17:35:45 -0700 (PDT) Received: from authenticated-user (box.fidei.email [71.19.144.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by box.fidei.email (Postfix) with ESMTPSA id E716F81041; Mon, 5 Sep 2022 20:35:44 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1662424545; bh=31tak+bQ7sOpodTtj1F9GEdWxgKjOvfSzMwGFTIcn7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MmowLzgV+u+yd1LjLrWPbLXKZHegJX25ISzMSxcXNcQwWXZiDdTyJETqcxxEGzaoW p6QfM9QVZs3V2JWjHGbIkWDDus/hxcnCqBPVnGJvo7d/lrcHb6CYq7C2hy0F1f7kCf kNbg08PFe26HCBrESL5k6imDM/WIPU0rlsqsG+7/U817TH4oCSSxmqj+T9zrdmsSFu J86IqfDingkEBb0SrwDnxFvhZVaozYqFU+EgqgxW1qPg9k+D76Psl5WKC/CC3JIKNg 3kPHbTZIfaAIwbwH4/KOjD8/rhQyETRekPRQTDxL2hQ0SGSi5KvpFflPKMw4xACeBC D4uS9yIfxgTVg== From: Sweet Tea Dorminy To: "Theodore Y. Ts'o" , Jaegeuk Kim , Eric Biggers , Chris Mason , Josef Bacik , David Sterba , linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org, kernel-team@fb.com Cc: Omar Sandoval , Sweet Tea Dorminy Subject: [PATCH v2 03/20] fscrypt: add fscrypt_have_same_policy() to check inode compatibility Date: Mon, 5 Sep 2022 20:35:18 -0400 Message-Id: <59fe9cb2916e7bad3bc57abc211a35f0a85990bc.1662420176.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Omar Sandoval Btrfs will need to check whether inode policies are identical for various purposes: if two inodes want to share an extent, they must have the same policy, including key identifier; symlinks must not span the encrypted/unencrypted border; and certain encryption policies will allow btrfs to store one fscrypt_context for multiple objects. Therefore, add a function which allows checking the encryption policies of two inodes to ensure they are identical. Signed-off-by: Omar Sandoval Signed-off-by: Sweet Tea Dorminy --- fs/crypto/policy.c | 26 ++++++++++++++++++++++++++ include/linux/fscrypt.h | 1 + 2 files changed, 27 insertions(+) diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 80b8ca0f340b..ed8b7b6531e5 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -415,6 +415,32 @@ static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy) return fscrypt_policy_from_context(policy, &ctx, ret); } +/** + * fscrypt_have_same_policy() - check whether two inodes have the same policy + * @inode1: the first inode + * @inode2: the second inode + * + * Return: %true if equal, else %false + */ +int fscrypt_have_same_policy(struct inode *inode1, struct inode *inode2) +{ + union fscrypt_policy policy1, policy2; + int err; + + if (!IS_ENCRYPTED(inode1) && !IS_ENCRYPTED(inode2)) + return true; + else if (!IS_ENCRYPTED(inode1) || !IS_ENCRYPTED(inode2)) + return false; + err = fscrypt_get_policy(inode1, &policy1); + if (err) + return err; + err = fscrypt_get_policy(inode2, &policy2); + if (err) + return err; + return fscrypt_policies_equal(&policy1, &policy2); +} +EXPORT_SYMBOL(fscrypt_have_same_policy); + static int set_encryption_policy(struct inode *inode, const union fscrypt_policy *policy) { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a4e00314c91b..16d2252d5562 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -318,6 +318,7 @@ static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) void fscrypt_free_bounce_page(struct page *bounce_page); /* policy.c */ +int fscrypt_have_same_policy(struct inode *inode1, struct inode *inode2); int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg); int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg); int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg);