From patchwork Thu Mar 31 11:22:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12796984 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 52C27C433FE for ; Thu, 31 Mar 2022 11:23:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235104AbiCaLZi (ORCPT ); Thu, 31 Mar 2022 07:25:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235091AbiCaLZa (ORCPT ); Thu, 31 Mar 2022 07:25:30 -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 C46CD6177; Thu, 31 Mar 2022 04:23:41 -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 559A7615B1; Thu, 31 Mar 2022 11:23:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE40EC340ED; Thu, 31 Mar 2022 11:23:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648725820; bh=oRCBnn7kgkdw7xTjPeB7+5HZ/LNct9wkcy1uiAQq5z4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g/+3T36UJr+0tqOb8CmWtf+mT+Ppq0B34ZarJVGk2JSrX/0M95d/GzpEO8SunYszg 4T1t/MQGGyxZ28Ld6Qt5sOoEnUyV/vYdX+ZaVKj4CyXvUEPWkpxn/SiMnqlVlZOAy1 8WI/zFufJfUIyT32SCMYTM/jnF8CBfVsmIPK4ejwx6AnmQK309Ohg0fE5+V33hnCxF YoTJlozaAFom78AzUZ5yyt1FbVqtZnPUXIZmEOOdCcJFRe4TNHgbV3LUR/8h5yVRVd eTtXFYMn2F8eYzNUetkp30+LNcIwUv/iloKr5LKa0qnXSocu6Ai01CjqiQE5Zn71zD 713sTxoi9MV1Q== 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 v3 01/19] fs: add two trivial lookup helpers Date: Thu, 31 Mar 2022 13:22:59 +0200 Message-Id: <20220331112318.1377494-2-brauner@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220331112318.1377494-1-brauner@kernel.org> References: <20220331112318.1377494-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5711; h=from:subject; bh=oRCBnn7kgkdw7xTjPeB7+5HZ/LNct9wkcy1uiAQq5z4=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSS59ovLcu74qJa3e/4D9sSqjEd6k7+lLw7kirq7unSKTPWL s9m/O0pZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACZS18jw36XT7rjG/5xJkdse9Rr3r3 b7pSaiL7fhpHqszdHlTgtnz2X4zcIawF7uuCtU8F3rSZkZKa9Ejjw0P223KJO5NcA/in87KwA= 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(). --- 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 Thu Mar 31 11:23:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 12796985 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 A8842C433F5 for ; Thu, 31 Mar 2022 11:24:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235098AbiCaLZq (ORCPT ); Thu, 31 Mar 2022 07:25:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235093AbiCaLZo (ORCPT ); Thu, 31 Mar 2022 07:25:44 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B672E647C; Thu, 31 Mar 2022 04:23:49 -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 4AD68B81BE2; Thu, 31 Mar 2022 11:23:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 361BFC340ED; Thu, 31 Mar 2022 11:23:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648725827; bh=HwFM2AHDJska7l0jW4kKAU7PP/QDhohkhcYMbwlAP34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VHZ6w53NOwGoc4aL7+/NoGZWOYS37jtoyc/bZuzLNNfw9qtEatrsYP9adoGws8Y/O 08AT70Pkr49P6+YlvwaRBf3Fl/wKJIdK7LNmOSBjq12pVaYwEIVugPYxuhmIgd1M1o Ql/JtLYyJiUmWTZ6xupkkTLHwXLBtOxDbk9fbnsdbgzWVnNiPAQcRLOMIGeSwff9rT jFKFR6XraoflC5ySA0drb8bBEaeDyNFWiKnFHj6t2E1R7fZQo+12bTEFMsAYq3nqLu qlGqsZnJNPWorc1LqGLiOepHz1hx7BdGDRJ/zDJKGAaQQ+qgPdBoB1PmcbozhVd60l WsCsbvXXiNfFg== 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 v3 02/19] exportfs: support idmapped mounts Date: Thu, 31 Mar 2022 13:23:00 +0200 Message-Id: <20220331112318.1377494-3-brauner@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220331112318.1377494-1-brauner@kernel.org> References: <20220331112318.1377494-1-brauner@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1927; h=from:subject; bh=HwFM2AHDJska7l0jW4kKAU7PP/QDhohkhcYMbwlAP34=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMSS59ouf/L9sruKTxNrVXvGbV/786LJlxdH2ohTba0+7HrFN Nqrz7ChlYRDjYpAVU2RxaDcJl1vOU7HZKFMDZg4rE8gQBi5OAZjIlASGv9JT56vHSlaFau891+j+Qe FsyoR5K423lySc/NzYvO61Zx3DP0XJFXsT7s2ovLtvr+DyedlzX1eEfXoSy7VgrQ6v+ZpZ/TwA 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 --- 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);