From patchwork Thu Oct 20 16:58:21 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: 13013787 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 3BB7BC433FE for ; Thu, 20 Oct 2022 16:59:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229846AbiJTQ7I (ORCPT ); Thu, 20 Oct 2022 12:59:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229887AbiJTQ7G (ORCPT ); Thu, 20 Oct 2022 12:59:06 -0400 Received: from box.fidei.email (box.fidei.email [71.19.144.250]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFE3019ABE1; Thu, 20 Oct 2022 09:59:04 -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 81596811B9; Thu, 20 Oct 2022 12:59:03 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dorminy.me; s=mail; t=1666285143; bh=m68pzGpTBuRr0q39jXG75JcKJtUdtM4aUKLmegEGH3M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LPySywXh7e06fv3fdtscd0z0HyoJGNVzQNU+Qa2MlvzcDe3pqfzODxbXzOioMy/oU aYgW3JpxPZFYE3XKzJBg2Q0GBpPlHLVZTxTGyjYiDl+8NG0kYoXim9oRDAcezBITKH /DHnMHWz9yPff4y2ALU5pHgXNqY50KFTOscSYYq0QSj3ihkwYJVbnEZYYOeRk0p7B6 UJ1iS6Kl73va5jwagdD1zrxk0foq4lNqmuwU9v3/nZeyO/a3J4WEAy2UWRWCK/F3oO xPinMvFHX5M5YH6w696tpZlM1VXDOwQzGlbpn9uzNBXE40ZVnDc/NdRS4JQXG5jaw8 65VBBLIIiy8cQ== 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@meta.com Cc: Omar Sandoval , Sweet Tea Dorminy Subject: [PATCH v3 02/22] fscrypt: add fscrypt_have_same_policy() to check inode compatibility Date: Thu, 20 Oct 2022 12:58:21 -0400 Message-Id: <48538f6e8b733d4e273510491a40a162545a7300.1666281277.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 | 7 +++++++ 2 files changed, 33 insertions(+) diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 46757c3052ef..b7c4820a8001 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 they are definitely 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 false; + err = fscrypt_get_policy(inode2, &policy2); + if (err) + return false; + 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 4cdff7c15544..9cc5a61c1200 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -313,6 +313,7 @@ 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); @@ -490,6 +491,12 @@ static inline void fscrypt_free_bounce_page(struct page *bounce_page) } /* policy.c */ +static inline int fscrypt_have_same_policy(struct inode *inode1, + struct inode *inode2) +{ + return 1; +} + static inline int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg) {