From patchwork Thu Aug 25 13:31:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 599994 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 CD7CFC04AA5 for ; Thu, 25 Aug 2022 13:32:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242846AbiHYNcp (ORCPT ); Thu, 25 Aug 2022 09:32:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242843AbiHYNcW (ORCPT ); Thu, 25 Aug 2022 09:32:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77064B5E43 for ; Thu, 25 Aug 2022 06:31:56 -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 601E0B8290E for ; Thu, 25 Aug 2022 13:31:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94994C433C1; Thu, 25 Aug 2022 13:31:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661434313; bh=ycDM4ZYpnKkGlUiDa9ULqAmwQ3hJkxNg6y/psJXgIEc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q6VRpfprl9khoqFK2JnNlhUZ3Ru3QSLZJZSfzNju3DGlsIkKYJvuFiMjI7sSRYEGL Gi213Su6yReLYc1j0ZF8BPOhGk0L7qRkwYIiPj6CnY/aXe4ok+ek9uoFYu1S3Nnq4Z Pi0Q0Uueitulnn9mMBqaSUzR19EkETW3OU/luOByUI/e1B88NvUCJbp/jhNyJt1OcS 6XPxxCQXT/bbXA9rlx4gmkfYxO12oMSgQ0IMcEtn4kW6e+DrrwlHxocYo8YL4Qd4Vz Xzlv4NBIbFeifTqRpAvgysT5HzvoV+GnL4O4zA51JRI073U1D17oYZ6dRLVhbGlz88 Ky3EZC5h1+KNA== From: Jeff Layton To: xiubli@redhat.com, idryomov@gmail.com Cc: lhenriques@suse.de, ceph-devel@vger.kernel.org Subject: [PATCH v15 26/29] ceph: add support for handling encrypted snapshot names Date: Thu, 25 Aug 2022 09:31:29 -0400 Message-Id: <20220825133132.153657-27-jlayton@kernel.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220825133132.153657-1-jlayton@kernel.org> References: <20220825133132.153657-1-jlayton@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org From: Luís Henriques 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 Reviewed-by: Xiubo Li Signed-off-by: Jeff Layton --- fs/ceph/crypto.c | 190 ++++++++++++++++++++++++++++++++++++++++------- fs/ceph/crypto.h | 4 +- 2 files changed, 165 insertions(+), 29 deletions(-) diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c index 65c7c83db431..35a2ccfe6899 100644 --- a/fs/ceph/crypto.c +++ b/fs/ceph/crypto.c @@ -189,16 +189,100 @@ 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 (in decimal) 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, 10, &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_find_inode(parent->i_sb, vino); + if (!dir) { + /* This can happen if we're not mounting cephfs on the root */ + dir = ceph_get_inode(parent->i_sb, vino, NULL); + if (!dir) + dir = ERR_PTR(-ENOENT); + } + 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; + + 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; - if (!fscrypt_has_encryption_key(parent)) { + if (!fscrypt_has_encryption_key(dir)) { memcpy(buf, d_name->name, d_name->len); - return d_name->len; + elen = d_name->len; + goto out; } /* @@ -207,18 +291,22 @@ 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 */ @@ -234,12 +322,30 @@ int ceph_encode_encrypted_dname(const struct inode *parent, struct qstr *d_name, /* base64 encode the encrypted name */ elen = ceph_base64_encode(cryptbuf, len, buf); - kfree(cryptbuf); dout("base64-encoded ciphertext name = %.*s\n", elen, buf); + + /* To understand the 240 limit, see CEPH_NOHASH_NAME_MAX comments */ + WARN_ON(elen > 240); + if ((elen > 0) && (dir != parent)) { + char tmp_buf[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) { + if ((dir->i_state & I_NEW)) + discard_new_inode(dir); + else + 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)); @@ -264,29 +370,42 @@ 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; - - if (!IS_ENCRYPTED(fname->dir)) { - oname->name = fname->name; - oname->len = fname->name_len; - return 0; - } + char *name = fname->name; + int name_len = fname->name_len; + int ret; /* Sanity check that the resulting name will fit in the buffer */ 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 '_' */ + } + + if (!IS_ENCRYPTED(dir)) { + oname->name = fname->name; + oname->len = fname->name_len; + ret = 0; + goto out_inode; + } + + 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 @@ -294,7 +413,8 @@ 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) { @@ -303,11 +423,11 @@ 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 = ceph_base64_decode(fname->name, fname->name_len, tname->name); + declen = ceph_base64_decode(name, name_len, tname->name); if (declen <= 0) { ret = -EIO; goto out; @@ -319,9 +439,25 @@ 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[CEPH_BASE64_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)) { + if ((dir->i_state & I_NEW)) + discard_new_inode(dir); + else + iput(dir); + } return ret; } diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h index d1726307bdb8..c6ee993f4ec8 100644 --- a/fs/ceph/crypto.h +++ b/fs/ceph/crypto.h @@ -101,8 +101,8 @@ 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) {