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 9075DC636D4 for ; Wed, 8 Feb 2023 06:21:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230223AbjBHGVn (ORCPT ); Wed, 8 Feb 2023 01:21:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229895AbjBHGVj (ORCPT ); Wed, 8 Feb 2023 01:21:39 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C52C1410B7; Tue, 7 Feb 2023 22:21:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 7218EB81C0B; Wed, 8 Feb 2023 06:21:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC55DC433D2; Wed, 8 Feb 2023 06:21:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675837295; bh=rXzimvd4PWdjTx5BBrxxERaITqXWUNGccCwAWr6IKjY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bqgr3pjenH4hhu5yGdWxOmuBDTfjE4KLBRmr1eWNY3senk1DChomHChHvaaxF6sbw WFt0IatwITKGVY/itxERVpapqWkjt5alhkueEyIKT84lQoCu0gAZ4T1uEu4FJf33/o heMAhP1Ezd9x0FPiBMslUu7RBEXu3HgMborHvzBMxsapUwcOEVrGe3o0JmYKEwck9m S2m6eg9Fv1O+XZQUCAASPtvuI1I1bozwdJGolV70KdhTahQQadD71tVagZeGiTGqSg zLKtosWgeOdtBPa38BSfliQolz1TEODI3gol34EYGKeYBQmVPlK7+cRjlDgxXc/dC3 T73UdOlm3P/mQ== From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Linus Torvalds Subject: [PATCH 1/5] fscrypt: add the test dummy encryption key on-demand Date: Tue, 7 Feb 2023 22:21:03 -0800 Message-Id: <20230208062107.199831-2-ebiggers@kernel.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230208062107.199831-1-ebiggers@kernel.org> References: <20230208062107.199831-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Eric Biggers When the key for an inode is not found but the inode is using the test_dummy_encryption policy, automatically add the test_dummy_encryption key to the filesystem keyring. This eliminates the need for all the individual filesystems to do this at mount time, which is a bit tricky to clean up from on failure. Note: this covers the call to fscrypt_find_master_key() from inode key setup, but not from the fscrypt ioctls. So, this isn't *exactly* the same as the key being present from the very beginning. I think we can tolerate that, though, since the inode key setup caller is the only one that actually matters in the context of test_dummy_encryption. Signed-off-by: Eric Biggers --- fs/crypto/fscrypt_private.h | 1 + fs/crypto/keysetup.c | 25 +++++++++++++++++++++++-- fs/crypto/policy.c | 3 +-- 3 files changed, 25 insertions(+), 4 deletions(-) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 316a778cec0ff..17dd33d9a522e 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -651,6 +651,7 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1, const union fscrypt_policy *policy2); int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, struct fscrypt_key_specifier *key_spec); +const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb); bool fscrypt_supported_policy(const union fscrypt_policy *policy_u, const struct inode *inode); int fscrypt_policy_from_context(union fscrypt_policy *policy_u, diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 94757ccd30568..20323c0ba4c5e 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -438,6 +438,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, bool need_dirhash_key, struct fscrypt_master_key **mk_ret) { + struct super_block *sb = ci->ci_inode->i_sb; struct fscrypt_key_specifier mk_spec; struct fscrypt_master_key *mk; int err; @@ -450,8 +451,28 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, if (err) return err; - mk = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec); - if (!mk) { + mk = fscrypt_find_master_key(sb, &mk_spec); + if (unlikely(!mk)) { + const union fscrypt_policy *dummy_policy = + fscrypt_get_dummy_policy(sb); + + /* + * Add the test_dummy_encryption key on-demand. In principle, + * it should be added at mount time. Do it here instead so that + * the individual filesystems don't need to worry about adding + * this key at mount time and cleaning up on mount failure. + */ + if (dummy_policy && + fscrypt_policies_equal(dummy_policy, &ci->ci_policy)) { + struct fscrypt_dummy_policy tmp = { dummy_policy }; + + err = fscrypt_add_test_dummy_key(sb, &tmp); + if (err) + return err; + mk = fscrypt_find_master_key(sb, &mk_spec); + } + } + if (unlikely(!mk)) { if (ci->ci_policy.version != FSCRYPT_POLICY_V1) return -ENOKEY; diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 893661b523769..69dca4ff5f488 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -53,8 +53,7 @@ int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy, } } -static const union fscrypt_policy * -fscrypt_get_dummy_policy(struct super_block *sb) +const union fscrypt_policy *fscrypt_get_dummy_policy(struct super_block *sb) { if (!sb->s_cop->get_dummy_policy) return NULL; -- 2.39.1