From patchwork Mon Apr 4 10:51:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12800111 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 A5628C433EF for ; Mon, 4 Apr 2022 10:52:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358359AbiDDKyw (ORCPT ); Mon, 4 Apr 2022 06:54:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245571AbiDDKyv (ORCPT ); Mon, 4 Apr 2022 06:54:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 102133CFDD; Mon, 4 Apr 2022 03:52:56 -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 dfw.source.kernel.org (Postfix) with ESMTPS id A137060018; Mon, 4 Apr 2022 10:52:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFEC0C2BBE4; Mon, 4 Apr 2022 10:52:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649069575; bh=b1kcnKYxSZsA1/o0cskxEbRLwGuElGZq/Yk+v1v7wwE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eHXiqjNv7uvtCHe3sTzF1jkfyWS4t6J7ZdoE3CuQhfN9BiBQE7qJIcKFxEg1jB+ZP xlpcVOMfMQtMv3jKYKNjJfJmcBJKwnHsw2UycLv8QiigcSx0LrckSG5HgS8w6qTkd6 DzwphEPS2PvCly9pmwKNSTmhiqylu8QATUD5LdDrm9vgHlW8j0scFgGzjsipS6MDsi 3H8AeLsDNvSco0/FBTngbxWMBWx8XEJvGvobT8cpp5ldH+PbHPZ9u8fWMuQXCtrtNy kGXwvVWyoo8hlo3MEmBqFaPkbd2egwjVe/9Ha7BvGGHOc0rBgvf/yJbHKxXyPuYPDQ b/66xYDSAEBoA== From: Christian Brauner To: Amir Goldstein , Christoph Hellwig , Miklos Szeredi , Al Viro Cc: Christian Brauner , linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, Aleksa Sarai , Giuseppe Scrivano , Rodrigo Campos Catelin , Seth Forshee , Luca Bocassi , Lennart Poettering , =?utf-8?q?St=C3=A9phane_Graber?= Subject: [PATCH v4 01/19] fs: add two trivial lookup helpers Date: Mon, 4 Apr 2022 12:51:40 +0200 Message-Id: <20220404105159.1567595-2-brauner@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220404105159.1567595-1-brauner@kernel.org> References: <20220404105159.1567595-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5734; h=from:subject; bh=b1kcnKYxSZsA1/o0cskxEbRLwGuElGZq/Yk+v1v7wwE=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSR5nT2ktn5V8yadzrfbdp+fzOh0e3LXC8e479Mu9mkwWLyU 2lhzpqOUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAiR3MYfjIGRq0rbd5WH6IwrVV5S/ 28JxutUq//WC//5Xdh5peaxihGhlcufyKTngn+rIzPmFXv7XOeMfr/cu7MdctFzC4+OrRamg0A X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Similar to the addition of lookup_one() add a version of lookup_one_unlocked() and lookup_one_positive_unlocked() that take idmapped mounts into account. This is required to port overlay to support idmapped base layers. Cc: Tested-by: Giuseppe Scrivano Reviewed-by: Amir Goldstein Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft) --- /* v2 */ unchanged /* v3 */ - Christoph Hellwig : - Wrap overly long lines. - Add kerneldoc for lookup_one_positive_unlocked(). /* v4 */ unchanged --- fs/namei.c | 69 ++++++++++++++++++++++++++++++++++++------- include/linux/namei.h | 6 ++++ 2 files changed, 65 insertions(+), 10 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 3f1829b3ab5b..d76f4dde6179 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2768,7 +2768,8 @@ struct dentry *lookup_one(struct user_namespace *mnt_userns, const char *name, EXPORT_SYMBOL(lookup_one); /** - * lookup_one_len_unlocked - filesystem helper to lookup single pathname component + * lookup_one_unlocked - filesystem helper to lookup single pathname component + * @mnt_userns: idmapping of the mount the lookup is performed from * @name: pathname component to lookup * @base: base directory to lookup from * @len: maximum length @len should be interpreted to @@ -2779,14 +2780,15 @@ EXPORT_SYMBOL(lookup_one); * Unlike lookup_one_len, it should be called without the parent * i_mutex held, and will take the i_mutex itself if necessary. */ -struct dentry *lookup_one_len_unlocked(const char *name, - struct dentry *base, int len) +struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns, + const char *name, struct dentry *base, + int len) { struct qstr this; int err; struct dentry *ret; - err = lookup_one_common(&init_user_ns, name, base, len, &this); + err = lookup_one_common(mnt_userns, name, base, len, &this); if (err) return ERR_PTR(err); @@ -2795,6 +2797,58 @@ struct dentry *lookup_one_len_unlocked(const char *name, ret = lookup_slow(&this, base, 0); return ret; } +EXPORT_SYMBOL(lookup_one_unlocked); + +/** + * lookup_one_positive_unlocked - filesystem helper to lookup single + * pathname component + * @mnt_userns: idmapping of the mount the lookup is performed from + * @name: pathname component to lookup + * @base: base directory to lookup from + * @len: maximum length @len should be interpreted to + * + * This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns + * known positive or ERR_PTR(). This is what most of the users want. + * + * Note that pinned negative with unlocked parent _can_ become positive at any + * time, so callers of lookup_one_unlocked() need to be very careful; pinned + * positives have >d_inode stable, so this one avoids such problems. + * + * Note that this routine is purely a helper for filesystem usage and should + * not be called by generic code. + * + * The helper should be called without i_mutex held. + */ +struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns, + const char *name, + struct dentry *base, int len) +{ + struct dentry *ret = lookup_one_unlocked(mnt_userns, name, base, len); + if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) { + dput(ret); + ret = ERR_PTR(-ENOENT); + } + return ret; +} +EXPORT_SYMBOL(lookup_one_positive_unlocked); + +/** + * lookup_one_len_unlocked - filesystem helper to lookup single pathname component + * @name: pathname component to lookup + * @base: base directory to lookup from + * @len: maximum length @len should be interpreted to + * + * Note that this routine is purely a helper for filesystem usage and should + * not be called by generic code. + * + * Unlike lookup_one_len, it should be called without the parent + * i_mutex held, and will take the i_mutex itself if necessary. + */ +struct dentry *lookup_one_len_unlocked(const char *name, + struct dentry *base, int len) +{ + return lookup_one_unlocked(&init_user_ns, name, base, len); +} EXPORT_SYMBOL(lookup_one_len_unlocked); /* @@ -2808,12 +2862,7 @@ EXPORT_SYMBOL(lookup_one_len_unlocked); struct dentry *lookup_positive_unlocked(const char *name, struct dentry *base, int len) { - struct dentry *ret = lookup_one_len_unlocked(name, base, len); - if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) { - dput(ret); - ret = ERR_PTR(-ENOENT); - } - return ret; + return lookup_one_positive_unlocked(&init_user_ns, name, base, len); } EXPORT_SYMBOL(lookup_positive_unlocked); diff --git a/include/linux/namei.h b/include/linux/namei.h index e89329bb3134..caeb08a98536 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -69,6 +69,12 @@ extern struct dentry *lookup_one_len(const char *, struct dentry *, int); extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); extern struct dentry *lookup_positive_unlocked(const char *, struct dentry *, int); struct dentry *lookup_one(struct user_namespace *, const char *, struct dentry *, int); +struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns, + const char *name, struct dentry *base, + int len); +struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns, + const char *name, + struct dentry *base, int len); extern int follow_down_one(struct path *); extern int follow_down(struct path *); From patchwork Mon Apr 4 10:51:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12800112 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 493FBC433F5 for ; Mon, 4 Apr 2022 10:53:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358571AbiDDKzG (ORCPT ); Mon, 4 Apr 2022 06:55:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358561AbiDDKzE (ORCPT ); Mon, 4 Apr 2022 06:55:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 288BD3CFED; Mon, 4 Apr 2022 03:53:09 -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 dfw.source.kernel.org (Postfix) with ESMTPS id B846B60AE8; Mon, 4 Apr 2022 10:53:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEA4CC34110; Mon, 4 Apr 2022 10:53:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649069588; bh=DxTthHQCW6asftQXjQGow73DCTtmUV2NMx0blS7OttM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KO4XTTGUiNiUJPuDvhahZ+xPDpp8AWdRuz9QFPnTkzN166mdCocCUhkJkXuJptv2p qlTiElBVuM9rZuGVpb9//WEcSjjJHR5MuxwGDgXJeo4shmqT+864SrAePB/vDcnuZQ 936yJiXFZktHtS1mQky66QazsPpMNvoSfA+38Ezc5C1TYvUDgaUyvPQco63Vb5gVFm JXzZsG+QFjFHrzQF2pck+r7Eqg7mt9HGIfK6ow0Ui4JSG+4jt9srQ1DT4ccSxhCF6r wh16gjrqsA8sXsHKhjDbKxGzsEwksY/rDHupe9oVW9PHWYGkC+KCsm68zKCC+3M2zZ TbtBBRmqCZ+KA== From: Christian Brauner To: Amir Goldstein , Christoph Hellwig , Miklos Szeredi , Al Viro Cc: Christian Brauner , linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, Aleksa Sarai , Giuseppe Scrivano , Rodrigo Campos Catelin , Seth Forshee , Luca Bocassi , Lennart Poettering , =?utf-8?q?St=C3=A9phane_Graber?= , stable@vger.kernel.org Subject: [PATCH v4 02/19] exportfs: support idmapped mounts Date: Mon, 4 Apr 2022 12:51:41 +0200 Message-Id: <20220404105159.1567595-3-brauner@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220404105159.1567595-1-brauner@kernel.org> References: <20220404105159.1567595-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1950; h=from:subject; bh=DxTthHQCW6asftQXjQGow73DCTtmUV2NMx0blS7OttM=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSR5nT30tu6CB7eLT3D0/wUcTAesIq2t5ZjmLwzP3Vof0elt 2cbYUcrCIMbFICumyOLQbhIut5ynYrNRpgbMHFYmkCEMXJwCMJEj6Qz/81t2rvw8d/+Kaa4Jm7a7Xw qwNV3SYbZrW0bXBt6kU1emX2NkOLlL7+XJlus3hRVTFB99nf+xu2ebbvfU3iqPZevOnTy2hRcA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Make the two locations where exportfs helpers check permission to lookup a given inode idmapped mount aware by switching it to the lookup_one() helper. This is a bugfix for the open_by_handle_at() system call which doesn't take idmapped mounts into account currently. It's not tied to a specific commit so we'll just Cc stable. In addition this is required to support idmapped base layers in overlay. The overlay filesystem uses exportfs to encode and decode file handles for its index=on mount option and when nfs_export=on. Cc: Cc: Tested-by: Giuseppe Scrivano Reviewed-by: Amir Goldstein Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft) --- /* v2 */ unchanged /* v3 */ unchanged /* v4 */ unchanged --- fs/exportfs/expfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 0106eba46d5a..3ef80d000e13 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -145,7 +145,7 @@ static struct dentry *reconnect_one(struct vfsmount *mnt, if (err) goto out_err; dprintk("%s: found name: %s\n", __func__, nbuf); - tmp = lookup_one_len_unlocked(nbuf, parent, strlen(nbuf)); + tmp = lookup_one_unlocked(mnt_user_ns(mnt), nbuf, parent, strlen(nbuf)); if (IS_ERR(tmp)) { dprintk("%s: lookup failed: %d\n", __func__, PTR_ERR(tmp)); err = PTR_ERR(tmp); @@ -525,7 +525,8 @@ exportfs_decode_fh_raw(struct vfsmount *mnt, struct fid *fid, int fh_len, } inode_lock(target_dir->d_inode); - nresult = lookup_one_len(nbuf, target_dir, strlen(nbuf)); + nresult = lookup_one(mnt_user_ns(mnt), nbuf, + target_dir, strlen(nbuf)); if (!IS_ERR(nresult)) { if (unlikely(nresult->d_inode != result->d_inode)) { dput(nresult);