From nobody Mon Jun 22 22:47:32 2026 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 EFBDCC433EF for ; Tue, 15 Mar 2022 16:19:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350003AbiCOQVA (ORCPT ); Tue, 15 Mar 2022 12:21:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349987AbiCOQU6 (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 95CA61BEB6; Tue, 15 Mar 2022 09:19:45 -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 577372192D; 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=+0IpsQeH7sa3P2E/obisysTpWW1R6WUBwo48BxYnHy4=; b=DK2rpWjzAj9bBIYUTD2zrcg86/d3oDeK0Paf2TlxrorgZFCgHzFrqPcI1LB/de9QCMbsFT Cl4w47AGXGuKEW1ZLmu+oFIVmdszMRqfSsh3XDCd3RkhMr0g/G/eym/Vc5Wrf2tVRB8tdW Yt2E/soGd9RwgIhNLGaTuIhci7QorFM= 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=+0IpsQeH7sa3P2E/obisysTpWW1R6WUBwo48BxYnHy4=; b=8xgJKmkbmcOtufh6xL/OWc29N0lUjDxcrSjtf4hmRNdD+9QUzE6XKgOjnHj/kXQb5ah5+R ivtKly/EYu99gjDg== 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 E142913B4E; Tue, 15 Mar 2022 16:19:43 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id gN3mM5+8MGIKPQAAMHmgww (envelope-from ); Tue, 15 Mar 2022 16:19:43 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id e4d492a7; Tue, 15 Mar 2022 16:20:01 +0000 (UTC) From: =?UTF-8?q?Lu=C3=ADs=20Henriques?= To: Jeff Layton , Xiubo Li , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Lu=C3=ADs=20Henriques?= Subject: [RFC PATCH v2 1/3] ceph: add support for encrypted snapshot names Date: Tue, 15 Mar 2022 16:19:57 +0000 Message-Id: <20220315161959.19453-2-lhenriques@suse.de> In-Reply-To: <20220315161959.19453-1-lhenriques@suse.de> References: <20220315161959.19453-1-lhenriques@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since filenames in encrypted directories are already encrypted and shown as a base64-encoded string when the directory is locked, snapshot names should show a similar behaviour. Signed-off-by: Lu=C3=ADs Henriques Reviewed-by: Xiubo Li --- fs/ceph/inode.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index 7b670e2405c1..359e29896f16 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -91,9 +91,15 @@ struct inode *ceph_new_inode(struct inode *dir, struct d= entry *dentry, if (err < 0) goto out_err; =20 - err =3D ceph_fscrypt_prepare_context(dir, inode, as_ctx); - if (err) - goto out_err; + /* + * We'll skip setting fscrypt context for snapshots, leaving that for + * the handle_reply(). + */ + if (ceph_snap(dir) !=3D CEPH_SNAPDIR) { + err =3D ceph_fscrypt_prepare_context(dir, inode, as_ctx); + if (err) + goto out_err; + } =20 return inode; out_err: @@ -157,6 +163,7 @@ struct inode *ceph_get_snapdir(struct inode *parent) }; struct inode *inode =3D ceph_get_inode(parent->i_sb, vino, NULL); struct ceph_inode_info *ci =3D ceph_inode(inode); + int ret =3D -ENOTDIR; =20 if (IS_ERR(inode)) return inode; @@ -182,6 +189,22 @@ struct inode *ceph_get_snapdir(struct inode *parent) ci->i_rbytes =3D 0; ci->i_btime =3D ceph_inode(parent)->i_btime; =20 + /* if encrypted, just borrow fscrypt_auth from parent */ + if (IS_ENCRYPTED(parent)) { + struct ceph_inode_info *pci =3D ceph_inode(parent); + + ci->fscrypt_auth =3D kmemdup(pci->fscrypt_auth, + pci->fscrypt_auth_len, + GFP_KERNEL); + if (ci->fscrypt_auth) { + inode->i_flags |=3D S_ENCRYPTED; + ci->fscrypt_auth_len =3D pci->fscrypt_auth_len; + } else { + dout("Failed to alloc snapdir fscrypt_auth\n"); + ret =3D -ENOMEM; + goto err; + } + } if (inode->i_state & I_NEW) { inode->i_op =3D &ceph_snapdir_iops; inode->i_fop =3D &ceph_snapdir_fops; @@ -195,7 +218,7 @@ struct inode *ceph_get_snapdir(struct inode *parent) discard_new_inode(inode); else iput(inode); - return ERR_PTR(-ENOTDIR); + return ERR_PTR(ret); } =20 const struct inode_operations ceph_file_iops =3D { From nobody Mon Jun 22 22:47:32 2026 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 A1BD0C433EF for ; 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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=20Henriques?= To: Jeff Layton , Xiubo Li , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Lu=C3=ADs=20Henriques?= 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 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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: Lu=C3=ADs 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_reque= st *req, struct ceph_acl_se swap(req->r_fscrypt_auth, as->fscrypt_auth); } =20 -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 decrypt= ed, + * - - 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 =3D NULL; + struct ceph_vino vino =3D { .snap =3D CEPH_NOSNAP }; + char *inode_number; + char *name_end; + int orig_len =3D *name_len; + int ret =3D -EIO; + + /* Skip initial '_' */ + name++; + name_end =3D strrchr(name, '_'); + if (!name_end) { + dout("Failed to parse long snapshot name: %s\n", name); + return ERR_PTR(-EIO); + } + *name_len =3D (name_end - name); + if (*name_len <=3D 0) { + pr_err("Failed to parse long snapshot name\n"); + return ERR_PTR(-EIO); + } + + /* Get the inode number */ + inode_number =3D kmemdup_nul(name_end + 1, + orig_len - *name_len - 2, + GFP_KERNEL); + if (!inode_number) + return ERR_PTR(-ENOMEM); + ret =3D kstrtou64(inode_number, 0, &vino.ino); + if (ret) { + dout("Failed to parse inode number: %s\n", name); + dir =3D ERR_PTR(ret); + goto out; + } + + /* And finally the inode */ + dir =3D 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 =3D parent; + struct qstr iname; u32 len; + int name_len; int elen; int ret; - u8 *cryptbuf; + u8 *cryptbuf =3D NULL; =20 if (!fscrypt_has_encryption_key(parent)) { memcpy(buf, d_name->name, d_name->len); return d_name->len; } =20 + iname.name =3D d_name->name; + name_len =3D d_name->len; + + /* Handle the special case of snapshot names that start with '_' */ + if ((ceph_snap(dir) =3D=3D CEPH_SNAPDIR) && (name_len > 0) && + (iname.name[0] =3D=3D '_')) { + dir =3D parse_longname(parent, iname.name, &name_len); + if (IS_ERR(dir)) + return PTR_ERR(dir); + iname.name++; /* skip initial '_' */ + } + iname.len =3D 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 *p= arent, 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 =3D -ENAMETOOLONG; + goto out; + } =20 /* Allocate a buffer appropriate to hold the result */ cryptbuf =3D kmalloc(len > CEPH_NOHASH_NAME_MAX ? NAME_MAX : len, GFP_KER= NEL); - if (!cryptbuf) - return -ENOMEM; + if (!cryptbuf) { + elen =3D -ENOMEM; + goto out; + } =20 - ret =3D fscrypt_fname_encrypt(parent, d_name, cryptbuf, len); + ret =3D fscrypt_fname_encrypt(dir, &iname, cryptbuf, len); if (ret) { - kfree(cryptbuf); - return ret; + elen =3D ret; + goto out; } =20 /* hash the end if the name is long enough */ @@ -174,12 +255,24 @@ int ceph_encode_encrypted_dname(const struct inode *p= arent, struct qstr *d_name, =20 /* base64 encode the encrypted name */ elen =3D fscrypt_base64url_encode(cryptbuf, len, buf); - kfree(cryptbuf); dout("base64-encoded ciphertext name =3D %.*s\n", elen, buf); + + if ((elen > 0) && (dir !=3D parent)) { + char tmp_buf[FSCRYPT_BASE64URL_CHARS(NAME_MAX)]; + + elen =3D snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld", + elen, buf, dir->i_ino); + memcpy(buf, tmp_buf, elen); + } + +out: + kfree(cryptbuf); + if (dir !=3D parent) + iput(dir); return elen; } =20 -int ceph_encode_encrypted_fname(const struct inode *parent, struct dentry = *dentry, char *buf) +int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentr= y, char *buf) { WARN_ON_ONCE(!fscrypt_has_encryption_key(parent)); =20 @@ -204,11 +297,14 @@ int ceph_encode_encrypted_fname(const struct inode *p= arent, 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 =3D fname->dir; struct fscrypt_str _tname =3D FSTR_INIT(NULL, 0); struct fscrypt_str iname; + char *name =3D fname->name; + int name_len =3D fname->name_len; + int ret; =20 - if (!IS_ENCRYPTED(fname->dir)) { + if (!IS_ENCRYPTED(dir)) { oname->name =3D fname->name; oname->len =3D 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; =20 - ret =3D __fscrypt_prepare_readdir(fname->dir); + /* Handle the special case of snapshot names that start with '_' */ + if ((ceph_snap(dir) =3D=3D CEPH_SNAPDIR) && (name_len > 0) && + (name[0] =3D=3D '_')) { + dir =3D parse_longname(dir, name, &name_len); + if (IS_ERR(dir)) + return PTR_ERR(dir); + name++; /* skip initial '_' */ + } + + ret =3D __fscrypt_prepare_readdir(dir); if (ret) - return ret; + goto out_inode; =20 /* * 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 =3D fname->name; else @@ -234,7 +339,8 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, s= truct fscrypt_str *tname, oname->len =3D fname->name_len; if (is_nokey) *is_nokey =3D true; - return 0; + ret =3D 0; + goto out_inode; } =20 if (fname->ctext_len =3D=3D 0) { @@ -243,11 +349,11 @@ int ceph_fname_to_usr(const struct ceph_fname *fname,= struct fscrypt_str *tname, if (!tname) { ret =3D fscrypt_fname_alloc_buffer(NAME_MAX, &_tname); if (ret) - return ret; + goto out_inode; tname =3D &_tname; } =20 - declen =3D fscrypt_base64url_decode(fname->name, fname->name_len, tname-= >name); + declen =3D fscrypt_base64url_decode(name, name_len, tname->name); if (declen <=3D 0) { ret =3D -EIO; goto out; @@ -259,9 +365,21 @@ int ceph_fname_to_usr(const struct ceph_fname *fname, = struct fscrypt_str *tname, iname.len =3D fname->ctext_len; } =20 - ret =3D fscrypt_fname_disk_to_usr(fname->dir, 0, 0, &iname, oname); + ret =3D fscrypt_fname_disk_to_usr(dir, 0, 0, &iname, oname); + if (!ret && (dir !=3D fname->dir)) { + char tmp_buf[FSCRYPT_BASE64URL_CHARS(NAME_MAX)]; + + name_len =3D snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld", + oname->len, oname->name, dir->i_ino); + memcpy(oname->name, tmp_buf, name_len); + oname->len =3D name_len; + } + out: fscrypt_fname_free_buffer(&_tname); +out_inode: + if ((dir !=3D fname->dir) && !IS_ERR(dir)) + iput(dir); return ret; } =20 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_fsc= rypt_auth *fa) * smaller size. If the ciphertext name is longer than the value below, th= en * sha256 hash the remaining bytes. * - * 189 bytes =3D> 252 bytes base64-encoded, which is <=3D NAME_MAX (255) + * 180 bytes =3D> 240 bytes base64-encoded, which is <=3D 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) =20 void ceph_fscrypt_set_ops(struct super_block *sb); =20 @@ -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 *dentr= y, char *buf); =20 static inline int ceph_fname_alloc_buffer(struct inode *parent, struct fsc= rypt_str *fname) { From nobody Mon Jun 22 22:47:32 2026 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 3B4B6C433F5 for ; Tue, 15 Mar 2022 16:19:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350043AbiCOQVI (ORCPT ); Tue, 15 Mar 2022 12:21:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349991AbiCOQU7 (ORCPT ); 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Tue, 15 Mar 2022 16:20:01 +0000 (UTC) From: =?UTF-8?q?Lu=C3=ADs=20Henriques?= To: Jeff Layton , Xiubo Li , Ilya Dryomov Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Lu=C3=ADs=20Henriques?= Subject: [RFC PATCH v2 3/3] ceph: update documentation regarding snapshot naming limitations Date: Tue, 15 Mar 2022 16:19:59 +0000 Message-Id: <20220315161959.19453-4-lhenriques@suse.de> In-Reply-To: <20220315161959.19453-1-lhenriques@suse.de> References: <20220315161959.19453-1-lhenriques@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Signed-off-by: Lu=C3=ADs Henriques Reviewed-by: Xiubo Li --- Documentation/filesystems/ceph.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/filesystems/ceph.rst b/Documentation/filesystems= /ceph.rst index 4942e018db85..d487cabe792d 100644 --- a/Documentation/filesystems/ceph.rst +++ b/Documentation/filesystems/ceph.rst @@ -57,6 +57,16 @@ a snapshot on any subdirectory (and its nested contents)= in the system. Snapshot creation and deletion are as simple as 'mkdir .snap/foo' and 'rmdir .snap/foo'. =20 +Snapshot names have two limitations: + +* They can not start with an underscore ('_'), as these names are reserved + for internal usage by the MDS. +* They can not exceed 240 characters in size. This is because the MDS mak= es + use of long snapshot names internally, which follow the format: + `__`. Since filenames in general can't have + more than 255 characters, and `` takes 13 characters, the long + snapshot names can take as much as 255 - 1 - 1 - 13 =3D 240. + Ceph also provides some recursive accounting on directories for nested files and bytes. That is, a 'getfattr -d foo' on any directory in the system will reveal the total number of nested regular files and