From patchwork Mon Sep 6 12:55:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 12476927 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-24.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01FBEC433F5 for ; Mon, 6 Sep 2021 12:56:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0E5D6103D for ; Mon, 6 Sep 2021 12:56:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242551AbhIFM5q (ORCPT ); Mon, 6 Sep 2021 08:57:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:33768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231287AbhIFM5l (ORCPT ); Mon, 6 Sep 2021 08:57:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2F76F61027; Mon, 6 Sep 2021 12:56:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630932996; bh=O/AwEu+8xhvnu689PTlnCpo/8o52aKuxRGYULKMTl/Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jHwwDYIc1CzsAPGxNoxNkQg07+DndBdm6XxfC/qbgoKSo7aey4aL3n0KM/hQQnZbc tuQuxluCr0nGJlRsLOdQcU/6I7jtcUykbdgmZBV8TpJMu2GxyJsVuKXmc2PD0a9fSq rNRlPkLpTpDRQeiNMuWa5HNknmYg1wOL272N50bw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , linux-fscrypt@vger.kernel.org, Eric Biggers Subject: [PATCH 5.10 02/29] fscrypt: add fscrypt_symlink_getattr() for computing st_size Date: Mon, 6 Sep 2021 14:55:17 +0200 Message-Id: <20210906125449.840205593@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210906125449.756437409@linuxfoundation.org> References: <20210906125449.756437409@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers commit d18760560593e5af921f51a8c9b64b6109d634c2 upstream. Add a helper function fscrypt_symlink_getattr() which will be called from the various filesystems' ->getattr() methods to read and decrypt the target of encrypted symlinks in order to report the correct st_size. Detailed explanation: As required by POSIX and as documented in various man pages, st_size for a symlink is supposed to be the length of the symlink target. Unfortunately, st_size has always been wrong for encrypted symlinks because st_size is populated from i_size from disk, which intentionally contains the length of the encrypted symlink target. That's slightly greater than the length of the decrypted symlink target (which is the symlink target that userspace usually sees), and usually won't match the length of the no-key encoded symlink target either. This hadn't been fixed yet because reporting the correct st_size would require reading the symlink target from disk and decrypting or encoding it, which historically has been considered too heavyweight to do in ->getattr(). Also historically, the wrong st_size had only broken a test (LTP lstat03) and there were no known complaints from real users. (This is probably because the st_size of symlinks isn't used too often, and when it is, typically it's for a hint for what buffer size to pass to readlink() -- which a slightly-too-large size still works for.) However, a couple things have changed now. First, there have recently been complaints about the current behavior from real users: - Breakage in rpmbuild: https://github.com/rpm-software-management/rpm/issues/1682 https://github.com/google/fscrypt/issues/305 - Breakage in toybox cpio: https://www.mail-archive.com/toybox@lists.landley.net/msg07193.html - Breakage in libgit2: https://issuetracker.google.com/issues/189629152 (on Android public issue tracker, requires login) Second, we now cache decrypted symlink targets in ->i_link. Therefore, taking the performance hit of reading and decrypting the symlink target in ->getattr() wouldn't be as big a deal as it used to be, since usually it will just save having to do the same thing later. Also note that eCryptfs ended up having to read and decrypt symlink targets in ->getattr() as well, to fix this same issue; see commit 3a60a1686f0d ("eCryptfs: Decrypt symlink target for stat size"). So, let's just bite the bullet, and read and decrypt the symlink target in ->getattr() in order to report the correct st_size. Add a function fscrypt_symlink_getattr() which the filesystems will call to do this. (Alternatively, we could store the decrypted size of symlinks on-disk. But there isn't a great place to do so, and encryption is meant to hide the original size to some extent; that property would be lost.) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210702065350.209646-2-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/crypto/hooks.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/fscrypt.h | 7 +++++++ 2 files changed, 51 insertions(+) --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -379,3 +379,47 @@ err_kfree: return ERR_PTR(err); } EXPORT_SYMBOL_GPL(fscrypt_get_symlink); + +/** + * fscrypt_symlink_getattr() - set the correct st_size for encrypted symlinks + * @path: the path for the encrypted symlink being queried + * @stat: the struct being filled with the symlink's attributes + * + * Override st_size of encrypted symlinks to be the length of the decrypted + * symlink target (or the no-key encoded symlink target, if the key is + * unavailable) rather than the length of the encrypted symlink target. This is + * necessary for st_size to match the symlink target that userspace actually + * sees. POSIX requires this, and some userspace programs depend on it. + * + * This requires reading the symlink target from disk if needed, setting up the + * inode's encryption key if possible, and then decrypting or encoding the + * symlink target. This makes lstat() more heavyweight than is normally the + * case. However, decrypted symlink targets will be cached in ->i_link, so + * usually the symlink won't have to be read and decrypted again later if/when + * it is actually followed, readlink() is called, or lstat() is called again. + * + * Return: 0 on success, -errno on failure + */ +int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat) +{ + struct dentry *dentry = path->dentry; + struct inode *inode = d_inode(dentry); + const char *link; + DEFINE_DELAYED_CALL(done); + + /* + * To get the symlink target that userspace will see (whether it's the + * decrypted target or the no-key encoded target), we can just get it in + * the same way the VFS does during path resolution and readlink(). + */ + link = READ_ONCE(inode->i_link); + if (!link) { + link = inode->i_op->get_link(dentry, inode, &done); + if (IS_ERR(link)) + return PTR_ERR(link); + } + stat->size = strlen(link); + do_delayed_call(&done); + return 0; +} +EXPORT_SYMBOL_GPL(fscrypt_symlink_getattr); --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -252,6 +252,7 @@ int __fscrypt_encrypt_symlink(struct ino const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, unsigned int max_size, struct delayed_call *done); +int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat); static inline void fscrypt_set_ops(struct super_block *sb, const struct fscrypt_operations *s_cop) { @@ -575,6 +576,12 @@ static inline const char *fscrypt_get_sy return ERR_PTR(-EOPNOTSUPP); } +static inline int fscrypt_symlink_getattr(const struct path *path, + struct kstat *stat) +{ + return -EOPNOTSUPP; +} + static inline void fscrypt_set_ops(struct super_block *sb, const struct fscrypt_operations *s_cop) { From patchwork Mon Sep 6 12:55:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 12476929 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA723C433F5 for ; Mon, 6 Sep 2021 12:56:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A571761050 for ; Mon, 6 Sep 2021 12:56:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242661AbhIFM6A (ORCPT ); Mon, 6 Sep 2021 08:58:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:34088 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242321AbhIFM5n (ORCPT ); Mon, 6 Sep 2021 08:57:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E10CB60F92; Mon, 6 Sep 2021 12:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630932999; bh=OgYCzNSAmHAJIMchHWHi3CWoRBsZ0US8dQMiggFdiMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MKPYxcgD/zyD5jrJrHsLOWzgoGn13nZiOYuBOZ+qvA6dfIoYU1dfU3q4xHd7rb0l/ fdPlCN/UyMllR3anI3KzcncoUMGseh5QZlp024XoqZvpJuS8GlexqFOFIHS3rRyS+h YxT8WSlEd7L5uHZpe7cT8CsjvMP30mFXSXwnvJjY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , linux-fscrypt@vger.kernel.org, Eric Biggers Subject: [PATCH 5.10 03/29] ext4: report correct st_size for encrypted symlinks Date: Mon, 6 Sep 2021 14:55:18 +0200 Message-Id: <20210906125449.877712012@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210906125449.756437409@linuxfoundation.org> References: <20210906125449.756437409@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers commit 8c4bca10ceafc43b1ca0a9fab5fa27e13cbce99e upstream. The stat() family of syscalls report the wrong size for encrypted symlinks, which has caused breakage in several userspace programs. Fix this by calling fscrypt_symlink_getattr() after ext4_getattr() for encrypted symlinks. This function computes the correct size by reading and decrypting the symlink target (if it's not already cached). For more details, see the commit which added fscrypt_symlink_getattr(). Fixes: f348c252320b ("ext4 crypto: add symlink encryption") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210702065350.209646-3-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/ext4/symlink.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/fs/ext4/symlink.c +++ b/fs/ext4/symlink.c @@ -52,10 +52,19 @@ static const char *ext4_encrypted_get_li return paddr; } +static int ext4_encrypted_symlink_getattr(const struct path *path, + struct kstat *stat, u32 request_mask, + unsigned int query_flags) +{ + ext4_getattr(path, stat, request_mask, query_flags); + + return fscrypt_symlink_getattr(path, stat); +} + const struct inode_operations ext4_encrypted_symlink_inode_operations = { .get_link = ext4_encrypted_get_link, .setattr = ext4_setattr, - .getattr = ext4_getattr, + .getattr = ext4_encrypted_symlink_getattr, .listxattr = ext4_listxattr, }; From patchwork Mon Sep 6 12:55:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 12476931 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D60E3C433F5 for ; Mon, 6 Sep 2021 12:56:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0DD66103D for ; Mon, 6 Sep 2021 12:56:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242321AbhIFM6D (ORCPT ); Mon, 6 Sep 2021 08:58:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:33768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242562AbhIFM5q (ORCPT ); Mon, 6 Sep 2021 08:57:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A87AB61027; Mon, 6 Sep 2021 12:56:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630933002; bh=E3HJ9d2n6j8OrQBpEwSh17+Pc+P8fVeqz8kyX4r/JEI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dDx+kFi0W+AfCA4WYPl1PcIkO08jfY0bQpDhpYxkecHbKAVA1O0vlpaoQjE6/SYQy pKiYRgZ8F1MjgV2/pp3zXN27uJcrsFeThmMIs8VlRVjDXgm2W6x2kghv6UDRTiMJQA pmaX+C0/0ZvprklIhFzpK3r2CnVRjW0qa41OTr7A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , linux-fscrypt@vger.kernel.org, Eric Biggers Subject: [PATCH 5.10 04/29] f2fs: report correct st_size for encrypted symlinks Date: Mon, 6 Sep 2021 14:55:19 +0200 Message-Id: <20210906125449.916743809@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210906125449.756437409@linuxfoundation.org> References: <20210906125449.756437409@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers commit 461b43a8f92e68e96c4424b31e15f2b35f1bbfa9 upstream. The stat() family of syscalls report the wrong size for encrypted symlinks, which has caused breakage in several userspace programs. Fix this by calling fscrypt_symlink_getattr() after f2fs_getattr() for encrypted symlinks. This function computes the correct size by reading and decrypting the symlink target (if it's not already cached). For more details, see the commit which added fscrypt_symlink_getattr(). Fixes: cbaf042a3cc6 ("f2fs crypto: add symlink encryption") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210702065350.209646-4-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/namei.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -1307,9 +1307,18 @@ static const char *f2fs_encrypted_get_li return target; } +static int f2fs_encrypted_symlink_getattr(const struct path *path, + struct kstat *stat, u32 request_mask, + unsigned int query_flags) +{ + f2fs_getattr(path, stat, request_mask, query_flags); + + return fscrypt_symlink_getattr(path, stat); +} + const struct inode_operations f2fs_encrypted_symlink_inode_operations = { .get_link = f2fs_encrypted_get_link, - .getattr = f2fs_getattr, + .getattr = f2fs_encrypted_symlink_getattr, .setattr = f2fs_setattr, .listxattr = f2fs_listxattr, }; From patchwork Mon Sep 6 12:55:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 12476933 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB31FC433EF for ; Mon, 6 Sep 2021 12:57:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B717061076 for ; Mon, 6 Sep 2021 12:57:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242319AbhIFM6F (ORCPT ); Mon, 6 Sep 2021 08:58:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:34270 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242577AbhIFM5t (ORCPT ); Mon, 6 Sep 2021 08:57:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3D0536105A; Mon, 6 Sep 2021 12:56:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630933004; bh=jYdXm12L3MlnvpuqT1puIxRIpBLBiC5/PW3D8MdvVDw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j/FvZiEmSsbfJkOWyekfWHgC11w7iQaz3VJ1mLoESt7lZylDo4GUZdol5xuW7NFOy 2dCbuAFGYP6MfYELIs0xH+vkkeQmh9EReP0MvozZ2GOE/LwUT/X1SGjFeluI1VuL2/ VuKPYUkY/1Az1cfy3CrO+hj4CFF26eShAlo6D9OE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , linux-fscrypt@vger.kernel.org, Eric Biggers Subject: [PATCH 5.10 05/29] ubifs: report correct st_size for encrypted symlinks Date: Mon, 6 Sep 2021 14:55:20 +0200 Message-Id: <20210906125449.957039185@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210906125449.756437409@linuxfoundation.org> References: <20210906125449.756437409@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Eric Biggers commit 064c734986011390b4d111f1a99372b7f26c3850 upstream. The stat() family of syscalls report the wrong size for encrypted symlinks, which has caused breakage in several userspace programs. Fix this by calling fscrypt_symlink_getattr() after ubifs_getattr() for encrypted symlinks. This function computes the correct size by reading and decrypting the symlink target (if it's not already cached). For more details, see the commit which added fscrypt_symlink_getattr(). Fixes: ca7f85be8d6c ("ubifs: Add support for encrypted symlinks") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210702065350.209646-5-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- fs/ubifs/file.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1629,6 +1629,16 @@ static const char *ubifs_get_link(struct return fscrypt_get_symlink(inode, ui->data, ui->data_len, done); } +static int ubifs_symlink_getattr(const struct path *path, struct kstat *stat, + u32 request_mask, unsigned int query_flags) +{ + ubifs_getattr(path, stat, request_mask, query_flags); + + if (IS_ENCRYPTED(d_inode(path->dentry))) + return fscrypt_symlink_getattr(path, stat); + return 0; +} + const struct address_space_operations ubifs_file_address_operations = { .readpage = ubifs_readpage, .writepage = ubifs_writepage, @@ -1654,7 +1664,7 @@ const struct inode_operations ubifs_file const struct inode_operations ubifs_symlink_inode_operations = { .get_link = ubifs_get_link, .setattr = ubifs_setattr, - .getattr = ubifs_getattr, + .getattr = ubifs_symlink_getattr, #ifdef CONFIG_UBIFS_FS_XATTR .listxattr = ubifs_listxattr, #endif