From patchwork Tue Mar 15 16:19:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 551899 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 A4479C433FE for ; Tue, 15 Mar 2022 16:19:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350010AbiCOQVC (ORCPT ); Tue, 15 Mar 2022 12:21:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349990AbiCOQU6 (ORCPT ); Tue, 15 Mar 2022 12:20:58 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AD5C1CFDF; Tue, 15 Mar 2022 09:19:46 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id D667A21902; Tue, 15 Mar 2022 16:19:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1647361184; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tACsPoKaAuDlM9T70UUmifqByODe7nAYiHju8sF0WHw=; b=iqeYWx7kDO0UgDEYgjc6ffhjzzqms4N67DA8b4otRZQZdW1TU8B2qEXFBI5solmZTO7Ymo f5bzkznK2y1TWoTBpwfXwImdLIHxAExuwIirsWBj/L92Kqi3zQ5Q+Yz9TsZj77ro6K4lsI FN0XuB+0PTehB4vHizxJf7sCd/LKT1Q= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1647361184; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tACsPoKaAuDlM9T70UUmifqByODe7nAYiHju8sF0WHw=; b=ONIRZqq79yLesrvUS38M+MJUpBbG2267LrM8tgeqPqilqpt627V0+vVkE4rmtT/DzcvkMC O1IybZQe9tRG+SBg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 6A5E213B4E; Tue, 15 Mar 2022 16:19:44 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id oK8CF6C8MGIKPQAAMHmgww (envelope-from ); Tue, 15 Mar 2022 16:19:44 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id 707ed306; Tue, 15 Mar 2022 16:20:01 +0000 (UTC) From: =?utf-8?q?Lu=C3=ADs_Henriques?= To: Jeff Layton , Xiubo Li , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Lu?= =?utf-8?q?=C3=ADs_Henriques?= Subject: [RFC PATCH v2 2/3] ceph: add support for handling encrypted snapshot names Date: Tue, 15 Mar 2022 16:19:58 +0000 Message-Id: <20220315161959.19453-3-lhenriques@suse.de> In-Reply-To: <20220315161959.19453-1-lhenriques@suse.de> References: <20220315161959.19453-1-lhenriques@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org When creating a snapshot, the .snap directories for every subdirectory will show the snapshot name in the "long format": # mkdir .snap/my-snap # ls my-dir/.snap/ _my-snap_1099511627782 Encrypted snapshots will need to be able to handle these snapshot names by encrypting/decrypting only the snapshot part of the string ('my-snap'). Also, since the MDS prevents snapshot names to be bigger than 240 characters it is necessary to adapt CEPH_NOHASH_NAME_MAX to accommodate this extra limitation. Signed-off-by: Luís Henriques --- fs/ceph/crypto.c | 158 +++++++++++++++++++++++++++++++++++++++++------ fs/ceph/crypto.h | 11 ++-- 2 files changed, 145 insertions(+), 24 deletions(-) diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index c125a79019b3..06a4b918201c 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -128,18 +128,95 @@ 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_dname(const struct inode *parent, struct qstr *d_name, char *buf) +/* + * User-created snapshots can't start with '_'. Snapshots that start with this + * character are special (hint: there aren't real snapshots) and use the + * following format: + * + * __ + * + * where: + * - - the real snapshot name that may need to be decrypted, + * - - the inode number for the actual snapshot + * + * This function parses these snapshot names and returns the inode + * . 'name_len' will also bet set with the + * length. + */ +static struct inode *parse_longname(const struct inode *parent, const char *name, + int *name_len) { + struct inode *dir = NULL; + struct ceph_vino vino = { .snap = CEPH_NOSNAP }; + char *inode_number; + char *name_end; + int orig_len = *name_len; + int ret = -EIO; + + /* Skip initial '_' */ + name++; + name_end = strrchr(name, '_'); + if (!name_end) { + dout("Failed to parse long snapshot name: %s\n", name); + return ERR_PTR(-EIO); + } + *name_len = (name_end - name); + if (*name_len <= 0) { + pr_err("Failed to parse long snapshot name\n"); + return ERR_PTR(-EIO); + } + + /* Get the inode number */ + inode_number = kmemdup_nul(name_end + 1, + orig_len - *name_len - 2, + GFP_KERNEL); + if (!inode_number) + return ERR_PTR(-ENOMEM); + ret = kstrtou64(inode_number, 0, &vino.ino); + if (ret) { + dout("Failed to parse inode number: %s\n", name); + dir = ERR_PTR(ret); + goto out; + } + + /* And finally the inode */ + dir = ceph_get_inode(parent->i_sb, vino, NULL); + if (IS_ERR(dir)) + dout("Can't find inode %s (%s)\n", inode_number, name); + +out: + kfree(inode_number); + return dir; +} + +int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name, char *buf) +{ + struct inode *dir = parent; + struct qstr iname; u32 len; + int name_len; int elen; int ret; - u8 *cryptbuf; + u8 *cryptbuf = NULL; if (!fscrypt_has_encryption_key(parent)) { memcpy(buf, d_name->name, d_name->len); return d_name->len; } + iname.name = d_name->name; + name_len = d_name->len; + + /* Handle the special case of snapshot names that start with '_' */ + if ((ceph_snap(dir) == CEPH_SNAPDIR) && (name_len > 0) && + (iname.name[0] == '_')) { + dir = parse_longname(parent, iname.name, &name_len); + if (IS_ERR(dir)) + return PTR_ERR(dir); + iname.name++; /* skip initial '_' */ + } + iname.len = name_len; + /* * convert cleartext d_name to ciphertext * if result is longer than CEPH_NOKEY_NAME_MAX, @@ -147,18 +224,22 @@ int ceph_encode_encrypted_dname(const struct inode *parent, struct qstr *d_name, * * See: fscrypt_setup_filename */ - if (!fscrypt_fname_encrypted_size(parent, d_name->len, NAME_MAX, &len)) - return -ENAMETOOLONG; + if (!fscrypt_fname_encrypted_size(dir, iname.len, NAME_MAX, &len)) { + elen = -ENAMETOOLONG; + goto out; + } /* Allocate a buffer appropriate to hold the result */ cryptbuf = kmalloc(len > CEPH_NOHASH_NAME_MAX ? NAME_MAX : len, GFP_KERNEL); - if (!cryptbuf) - return -ENOMEM; + if (!cryptbuf) { + elen = -ENOMEM; + goto out; + } - ret = fscrypt_fname_encrypt(parent, d_name, cryptbuf, len); + ret = fscrypt_fname_encrypt(dir, &iname, cryptbuf, len); if (ret) { - kfree(cryptbuf); - return ret; + elen = ret; + goto out; } /* hash the end if the name is long enough */ @@ -174,12 +255,24 @@ int ceph_encode_encrypted_dname(const struct inode *parent, struct qstr *d_name, /* base64 encode the encrypted name */ elen = fscrypt_base64url_encode(cryptbuf, len, buf); - kfree(cryptbuf); dout("base64-encoded ciphertext name = %.*s\n", elen, buf); + + if ((elen > 0) && (dir != parent)) { + char tmp_buf[FSCRYPT_BASE64URL_CHARS(NAME_MAX)]; + + elen = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld", + elen, buf, dir->i_ino); + memcpy(buf, tmp_buf, elen); + } + +out: + kfree(cryptbuf); + if (dir != parent) + iput(dir); return elen; } -int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf) +int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentry, char *buf) { WARN_ON_ONCE(!fscrypt_has_encryption_key(parent)); @@ -204,11 +297,14 @@ int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentr int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, struct fscrypt_str *oname, bool *is_nokey) { - int ret; + struct inode *dir = fname->dir; struct fscrypt_str _tname = FSTR_INIT(NULL, 0); struct fscrypt_str iname; + char *name = fname->name; + int name_len = fname->name_len; + int ret; - if (!IS_ENCRYPTED(fname->dir)) { + if (!IS_ENCRYPTED(dir)) { oname->name = fname->name; oname->len = fname->name_len; return 0; @@ -218,15 +314,24 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX) return -EIO; - ret = __fscrypt_prepare_readdir(fname->dir); + /* Handle the special case of snapshot names that start with '_' */ + if ((ceph_snap(dir) == CEPH_SNAPDIR) && (name_len > 0) && + (name[0] == '_')) { + dir = parse_longname(dir, name, &name_len); + if (IS_ERR(dir)) + return PTR_ERR(dir); + name++; /* skip initial '_' */ + } + + ret = __fscrypt_prepare_readdir(dir); if (ret) - return ret; + goto out_inode; /* * Use the raw dentry name as sent by the MDS instead of * generating a nokey name via fscrypt. */ - if (!fscrypt_has_encryption_key(fname->dir)) { + if (!fscrypt_has_encryption_key(dir)) { if (fname->no_copy) oname->name = fname->name; else @@ -234,7 +339,8 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, oname->len = fname->name_len; if (is_nokey) *is_nokey = true; - return 0; + ret = 0; + goto out_inode; } if (fname->ctext_len == 0) { @@ -243,11 +349,11 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, if (!tname) { ret = fscrypt_fname_alloc_buffer(NAME_MAX, &_tname); if (ret) - return ret; + goto out_inode; tname = &_tname; } - declen = fscrypt_base64url_decode(fname->name, fname->name_len, tname->name); + declen = fscrypt_base64url_decode(name, name_len, tname->name); if (declen <= 0) { ret = -EIO; goto out; @@ -259,9 +365,21 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname, iname.len = fname->ctext_len; } - ret = fscrypt_fname_disk_to_usr(fname->dir, 0, 0, &iname, oname); + ret = fscrypt_fname_disk_to_usr(dir, 0, 0, &iname, oname); + if (!ret && (dir != fname->dir)) { + char tmp_buf[FSCRYPT_BASE64URL_CHARS(NAME_MAX)]; + + name_len = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld", + oname->len, oname->name, dir->i_ino); + memcpy(oname->name, tmp_buf, name_len); + oname->len = name_len; + } + out: fscrypt_fname_free_buffer(&_tname); +out_inode: + if ((dir != fname->dir) && !IS_ERR(dir)) + iput(dir); return ret; } diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h index 185fb4799a6d..e38a842e02a6 100644 --- a/fs/ceph/crypto.h +++ b/fs/ceph/crypto.h @@ -76,13 +76,16 @@ static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa) * smaller size. If the ciphertext name is longer than the value below, then * sha256 hash the remaining bytes. * - * 189 bytes => 252 bytes base64-encoded, which is <= NAME_MAX (255) + * 180 bytes => 240 bytes base64-encoded, which is <= NAME_MAX (255) + * + * (Note: 240 bytes is the maximum size allowed for snapshot names to take into + * account the format: '__') * * Note that for long names that end up having their tail portion hashed, we * must also store the full encrypted name (in the dentry's alternate_name * field). */ -#define CEPH_NOHASH_NAME_MAX (189 - SHA256_DIGEST_SIZE) +#define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE) void ceph_fscrypt_set_ops(struct super_block *sb); @@ -91,8 +94,8 @@ 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_dname(const struct inode *parent, struct qstr *d_name, char *buf); -int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry *dentry, char *buf); +int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name, char *buf); +int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentry, char *buf); static inline int ceph_fname_alloc_buffer(struct inode *parent, struct fscrypt_str *fname) {