From patchwork Wed Apr 27 19:12:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 566776 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 E7337C433EF for ; Wed, 27 Apr 2022 19:24:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232732AbiD0T1z (ORCPT ); Wed, 27 Apr 2022 15:27:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233113AbiD0TTO (ORCPT ); Wed, 27 Apr 2022 15:19:14 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D45989322 for ; Wed, 27 Apr 2022 12:13:34 -0700 (PDT) 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 30280B8291B for ; Wed, 27 Apr 2022 19:13:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C19AC385A7; Wed, 27 Apr 2022 19:13:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651086811; bh=aZCBWdHBzzGojB76XlrwgBk/bZ2c4RnpxObaB8Tu1TY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TjyW6o7zU+NQ+VeOBOvNQm+UmWVgwk4ZNEXhbUz+uZ1RCT/I18qKCgYwPeCmBh8/i tW4t6+RZ/9RbnjusremhRLzmUmahNKMpcheHQNf5F6Px+c6m3k1eZZn2wIQXNqu12G tuzxw1184Xhhe7Wjs648BWTdEytQI0NieIMl5BTGXt/3GtQBXf+iSvl9Zm/qhx+0Ge vfh226sM/OYm2nC3kSG1Po8G71zHowL157JDcma/G4fcVutuUOMYUA1Ei1x6FvTlEN cm3IjJiU9m7E7S6EYTt83lIMozjmCKEKGksXnoJOQVerg/yLbmYyDX+k7mcQrcCOs7 xSw4oxf9EGIHQ== From: Jeff Layton To: ceph-devel@vger.kernel.org Cc: xiubli@redhat.com, lhenriques@suse.de, idryomov@gmail.com Subject: [PATCH v14 21/64] ceph: add encrypted fname handling to ceph_mdsc_build_path Date: Wed, 27 Apr 2022 15:12:31 -0400 Message-Id: <20220427191314.222867-22-jlayton@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220427191314.222867-1-jlayton@kernel.org> References: <20220427191314.222867-1-jlayton@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Allow ceph_mdsc_build_path to encrypt and base64 encode the filename when the parent is encrypted and we're sending the path to the MDS. In most cases, we just encrypt the filenames and base64 encode them, but when the name is longer than CEPH_NOHASH_NAME_MAX, we use a similar scheme to fscrypt proper, and hash the remaning bits with sha256. When doing this, we then send along the full crypttext of the name in the new alternate_name field of the MClientRequest. The MDS can then send that along in readdir responses and traces. Signed-off-by: Jeff Layton --- fs/ceph/crypto.c | 47 ++++++++++++++++++++++++++ fs/ceph/crypto.h | 8 +++++ fs/ceph/mds_client.c | 80 ++++++++++++++++++++++++++++++++++---------- 3 files changed, 117 insertions(+), 18 deletions(-) diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index fffbd47d9e43..921e62f860c4 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -187,3 +187,50 @@ void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req, struct ceph_acl_se { swap(req->r_fscrypt_auth, as->fscrypt_auth); } + +int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf) +{ + u32 len; + int elen; + int ret; + u8 *cryptbuf; + + WARN_ON_ONCE(!fscrypt_has_encryption_key(parent)); + + /* + * Convert cleartext d_name to ciphertext. If result is longer than + * CEPH_NOHASH_NAME_MAX, sha256 the remaining bytes + * + * See: fscrypt_setup_filename + */ + if (!fscrypt_fname_encrypted_size(parent, dentry->d_name.len, NAME_MAX, &len)) + return -ENAMETOOLONG; + + /* Allocate a buffer appropriate to hold the result */ + cryptbuf = kmalloc(len > CEPH_NOHASH_NAME_MAX ? NAME_MAX : len, GFP_KERNEL); + if (!cryptbuf) + return -ENOMEM; + + ret = fscrypt_fname_encrypt(parent, &dentry->d_name, cryptbuf, len); + if (ret) { + kfree(cryptbuf); + return ret; + } + + /* hash the end if the name is long enough */ + if (len > CEPH_NOHASH_NAME_MAX) { + u8 hash[SHA256_DIGEST_SIZE]; + u8 *extra = cryptbuf + CEPH_NOHASH_NAME_MAX; + + /* hash the extra bytes and overwrite crypttext beyond that point with it */ + sha256(extra, len - CEPH_NOHASH_NAME_MAX, hash); + memcpy(extra, hash, SHA256_DIGEST_SIZE); + len = CEPH_NOHASH_NAME_MAX + SHA256_DIGEST_SIZE; + } + + /* base64 encode the encrypted name */ + elen = ceph_base64_encode(cryptbuf, len, buf); + kfree(cryptbuf); + dout("base64-encoded ciphertext name = %.*s\n", elen, buf); + return elen; +} diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h index f5d38d8a1995..8abf10604722 100644 --- a/fs/ceph/crypto.h +++ b/fs/ceph/crypto.h @@ -6,6 +6,7 @@ #ifndef _CEPH_CRYPTO_H #define _CEPH_CRYPTO_H +#include #include struct ceph_fs_client; @@ -66,6 +67,7 @@ void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc); int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode, struct ceph_acl_sec_ctx *as); void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req, struct ceph_acl_sec_ctx *as); +int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf); #else /* CONFIG_FS_ENCRYPTION */ @@ -89,6 +91,12 @@ static inline void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req, struct ceph_acl_sec_ctx *as_ctx) { } + +static inline int ceph_encode_encrypted_fname(const struct inode *parent, + struct dentry *dentry, char *buf) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_FS_ENCRYPTION */ #endif diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 5c7c89a1343b..e31a5bec9afc 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -14,6 +14,7 @@ #include #include "super.h" +#include "crypto.h" #include "mds_client.h" #include "crypto.h" @@ -2385,18 +2386,27 @@ static inline u64 __get_oldest_tid(struct ceph_mds_client *mdsc) return mdsc->oldest_tid; } -/* - * Build a dentry's path. Allocate on heap; caller must kfree. Based - * on build_path_from_dentry in fs/cifs/dir.c. +/** + * ceph_mdsc_build_path - build a path string to a given dentry + * @dentry: dentry to which path should be built + * @plen: returned length of string + * @pbase: returned base inode number + * @for_wire: is this path going to be sent to the MDS? + * + * Build a string that represents the path to the dentry. This is mostly called + * for two different purposes: * - * If @stop_on_nosnap, generate path relative to the first non-snapped - * inode. + * 1) we need to build a path string to send to the MDS (for_wire == true) + * 2) we need a path string for local presentation (e.g. debugfs) (for_wire == false) + * + * The path is built in reverse, starting with the dentry. Walk back up toward + * the root, building the path until the first non-snapped inode is reached (for_wire) + * or the root inode is reached (!for_wire). * * Encode hidden .snap dirs as a double /, i.e. * foo/.snap/bar -> foo//bar */ -char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, - int stop_on_nosnap) +char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for_wire) { struct dentry *cur; struct inode *inode; @@ -2418,30 +2428,65 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, seq = read_seqbegin(&rename_lock); cur = dget(dentry); for (;;) { - struct dentry *temp; + struct dentry *parent; spin_lock(&cur->d_lock); inode = d_inode(cur); if (inode && ceph_snap(inode) == CEPH_SNAPDIR) { dout("build_path path+%d: %p SNAPDIR\n", pos, cur); - } else if (stop_on_nosnap && inode && dentry != cur && - ceph_snap(inode) == CEPH_NOSNAP) { + spin_unlock(&cur->d_lock); + parent = dget_parent(cur); + } else if (for_wire && inode && dentry != cur && ceph_snap(inode) == CEPH_NOSNAP) { spin_unlock(&cur->d_lock); pos++; /* get rid of any prepended '/' */ break; - } else { + } else if (!for_wire || !IS_ENCRYPTED(d_inode(cur->d_parent))) { pos -= cur->d_name.len; if (pos < 0) { spin_unlock(&cur->d_lock); break; } memcpy(path + pos, cur->d_name.name, cur->d_name.len); + spin_unlock(&cur->d_lock); + parent = dget_parent(cur); + } else { + int len, ret; + char buf[NAME_MAX]; + + /* + * Proactively copy name into buf, in case we need to present + * it as-is. + */ + memcpy(buf, cur->d_name.name, cur->d_name.len); + len = cur->d_name.len; + spin_unlock(&cur->d_lock); + parent = dget_parent(cur); + + ret = __fscrypt_prepare_readdir(d_inode(parent)); + if (ret < 0) { + dput(parent); + dput(cur); + return ERR_PTR(ret); + } + + if (fscrypt_has_encryption_key(d_inode(parent))) { + len = ceph_encode_encrypted_fname(d_inode(parent), cur, buf); + if (len < 0) { + dput(parent); + dput(cur); + return ERR_PTR(len); + } + } + pos -= len; + if (pos < 0) { + dput(parent); + break; + } + memcpy(path + pos, buf, len); } - temp = cur; - spin_unlock(&temp->d_lock); - cur = dget_parent(temp); - dput(temp); + dput(cur); + cur = parent; /* Are we at the root? */ if (IS_ROOT(cur)) @@ -2465,8 +2510,7 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, * A rename didn't occur, but somehow we didn't end up where * we thought we would. Throw a warning and try again. */ - pr_warn("build_path did not end path lookup where " - "expected, pos is %d\n", pos); + pr_warn("build_path did not end path lookup where expected (pos = %d)\n", pos); goto retry; } @@ -2486,7 +2530,7 @@ static int build_dentry_path(struct dentry *dentry, struct inode *dir, rcu_read_lock(); if (!dir) dir = d_inode_rcu(dentry->d_parent); - if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP) { + if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP && !IS_ENCRYPTED(dir)) { *pino = ceph_ino(dir); rcu_read_unlock(); *ppath = dentry->d_name.name;