From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 3CE06C10F00 for ; Sat, 7 Mar 2020 02:36:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C01B206CC for ; Sat, 7 Mar 2020 02:36:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="maDP+sv7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726968AbgCGCgj (ORCPT ); Fri, 6 Mar 2020 21:36:39 -0500 Received: from mail-pf1-f202.google.com ([209.85.210.202]:46419 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726897AbgCGCgj (ORCPT ); Fri, 6 Mar 2020 21:36:39 -0500 Received: by mail-pf1-f202.google.com with SMTP id q135so2798946pfc.13 for ; Fri, 06 Mar 2020 18:36:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eY0o7zJ9ID5RkUnCQ8ZBfY0aWmEieO+fgK45vUzTAmI=; b=maDP+sv7S5sg7dJ+wIj5K1mw8zKYw8OcIiPukgjB9zxHUGo+On7L3GC+ARA2qoCFrt vIBGoqJloHTM/uAbxgHebuEJeJ19PSqBv2MSP1dpjQIjklO815/0Gc247hDyju9YBpEr ICpkbEMJkPCMECSkW1EC4lwQYrxUSD65UPtAsURE+TGRjcHtmTS9w4izqCAdZkWq+KXs 2b9n/hik8XxhEwZBd35FbCld2A53Ae5EfQrqHQA0hgDr4cgkYeOoh3qWyeQQIpdgM2qz vRJgeDpbg2t71sHRRvbdbYRKLd9mFgXgnKPCPz82+oicZ9gBSIzzICZQvRvDb88n2sRS dGRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eY0o7zJ9ID5RkUnCQ8ZBfY0aWmEieO+fgK45vUzTAmI=; b=lg/L+PKj+a/adnZ9WMQ9ypko0Egj9RuaGqDlpgXDDgn6fZmgHawr3UxtmgJHAueJjG ear8dEZf68ogrhTOZP5Elt8dIv22lslT3Eegtow0ENU/cr097AqToSgGTOjlY1MDy3d+ 6I986Z6Pd88PPtzTc10xQ07DmMU2nhI79p3XV5zcVL/ZSnpKg/JpAntU0BvPVY1im8tp ezrmqsGhICl8AXO8toJTPg+HRA6bhlHfjNZzZUuc9RWKiqocDlzECkVIyH6jWIHGo/i+ YxoM7LW0sWqDT3EFIgfRiRf9TeBxwnBrXskw7ip2/i5lNYyAYHXm+ONkcaxkFyq+/5bm aokQ== X-Gm-Message-State: ANhLgQ1LGQ7o+TOngZB9VU+YOj526rfSwPYsrFTvrfRzXgH6loiQWfnv 3BXZqEAQOYZcW2wq+WKTAE0Oi7P1CBc= X-Google-Smtp-Source: ADFU+vvzA+1kQfLrYOGb8BKXwXlqs4orE2r9h0PUkhfDALGzmbnT0SpAK8/epSd/0whSxfO37yVzAKXtsmE= X-Received: by 2002:a17:90a:2466:: with SMTP id h93mr6538944pje.177.1583548598158; Fri, 06 Mar 2020 18:36:38 -0800 (PST) Date: Fri, 6 Mar 2020 18:36:05 -0800 In-Reply-To: <20200307023611.204708-1-drosen@google.com> Message-Id: <20200307023611.204708-3-drosen@google.com> Mime-Version: 1.0 References: <20200307023611.204708-1-drosen@google.com> X-Mailer: git-send-email 2.25.1.481.gfbce0eb801-goog Subject: [PATCH v8 2/8] fs: Add standard casefolding support From: Daniel Rosenberg To: "Theodore Ts'o" , linux-ext4@vger.kernel.org, Jaegeuk Kim , Chao Yu , linux-f2fs-devel@lists.sourceforge.net, Eric Biggers , linux-fscrypt@vger.kernel.org, Alexander Viro , Richard Weinberger Cc: linux-mtd@lists.infradead.org, Andreas Dilger , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Gabriel Krisman Bertazi , kernel-team@android.com, Daniel Rosenberg Content-Type: text/plain; charset="UTF-8" Sender: linux-fscrypt-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org This adds general supporting functions for filesystems that use utf8 casefolding. It provides standard dentry_operations and adds the necessary structures in struct super_block to allow this standardization. Signed-off-by: Daniel Rosenberg --- fs/libfs.c | 114 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 22 +++++++++ 2 files changed, 136 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index c686bd9caac67..0eaa63a9ae037 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -20,6 +20,8 @@ #include #include #include +#include +#include #include @@ -1361,3 +1363,115 @@ bool is_empty_dir_inode(struct inode *inode) return (inode->i_fop == &empty_dir_operations) && (inode->i_op == &empty_dir_inode_operations); } + +#ifdef CONFIG_UNICODE +/** + * needs_casefold - determine if casefolding applies for a given directory + * @dir: Folder to check + * + * This function returns true if dentries within this folder should be + * casefolded. If a folder is encrypted, but we don't have the key, it is not + * meaningful to casefold the no-key token name. + */ +bool needs_casefold(const struct inode *dir) +{ + return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding && + (!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir)); +} +EXPORT_SYMBOL(needs_casefold); + +/* + * Under RCU, small names may change, but utf8 expects a stable name + * This operates similarly to take_dentry_name_snapshot, except that there + * is no guarantee that it grabs a coherent string. + */ +static int make_name_stable(const struct unicode_map *um, + const struct dentry *dentry, struct qstr *entry, + char *buff) +{ + if (dentry->d_iname != (const unsigned char *)entry->name) + return 0; + + memcpy(buff, entry->name, entry->len + 1); + entry->name = buff; + return utf8_validate(um, entry); +} + +/** + * generic_ci_d_compare - generic implementation of d_compare for casefolding + * @dentry: Entry we are comparing against + * @len: length of str + * @str: name of the dentry, safely paired with len + * @name: qstr to test against + * + * This performs a case insensitive comparison between the given name and str. + * It can be used as d_compare for dentry_operations. + */ +int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, + const char *str, const struct qstr *name) +{ + const struct dentry *parent = READ_ONCE(dentry->d_parent); + const struct inode *inode = READ_ONCE(parent->d_inode); + const struct super_block *sb = dentry->d_sb; + const struct unicode_map *um = sb->s_encoding; + char small_name[DNAME_INLINE_LEN]; + struct qstr entry = QSTR_INIT(str, len); + int ret; + + if (!inode || !needs_casefold(inode)) + goto fallback; + + /* Under RCU, small names may change, but utf8 expects a stable name */ + if (make_name_stable(um, dentry, &entry, small_name)) + goto err; + ret = utf8_strncasecmp(um, name, &entry); + if (ret >= 0) + return ret; +err: + if (sb_has_enc_strict_mode(sb)) + return -EINVAL; +fallback: + if (len != name->len) + return 1; + return !!memcmp(str, name->name, len); +} +EXPORT_SYMBOL(generic_ci_d_compare); + +/** + * generic_ci_d_hash - generic implementation of d_hash for casefolding + * @dentry: Entry whose name we are hashing + * @len: length of str + * @qstr: name of the dentry, safely paired with len + * @str: qstr to set hash of + * + * This performs a case insensitive hash of the given str. + * If casefolding is not required, it leaves the hash unchanged. + */ +int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) +{ + const struct inode *inode = READ_ONCE(dentry->d_inode); + struct super_block *sb = dentry->d_sb; + const struct unicode_map *um = sb->s_encoding; + char small_name[DNAME_INLINE_LEN]; + struct qstr entry = QSTR_INIT(str->name, str->len); + int ret = 0; + + if (!inode || !needs_casefold(inode)) + return 0; + + if (make_name_stable(um, dentry, &entry, small_name)) + goto err; + ret = utf8_casefold_hash(um, dentry, &entry); + if (ret < 0) + goto err; + + return 0; +err: + if (sb_has_enc_strict_mode(sb)) + ret = -EINVAL; + else + ret = 0; + return ret; +} +EXPORT_SYMBOL(generic_ci_d_hash); +#endif diff --git a/include/linux/fs.h b/include/linux/fs.h index 3cd4fe6b845e7..8d20a3daa49a0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1382,6 +1382,12 @@ extern int send_sigurg(struct fown_struct *fown); #define SB_ACTIVE (1<<30) #define SB_NOUSER (1<<31) +/* These flags relate to encoding and casefolding, and are stored on disk */ +#define SB_ENC_STRICT_MODE_FL (1 << 0) + +#define sb_has_enc_strict_mode(sb) \ + (sb->s_encoding_flags & SB_ENC_STRICT_MODE_FL) + /* * Umount options */ @@ -1449,6 +1455,10 @@ struct super_block { #endif #ifdef CONFIG_FS_VERITY const struct fsverity_operations *s_vop; +#endif +#ifdef CONFIG_UNICODE + struct unicode_map *s_encoding; + u16 s_encoding_flags; #endif struct hlist_bl_head s_roots; /* alternate root dentries for NFS */ struct list_head s_mounts; /* list of mounts; _not_ for fs use */ @@ -3368,6 +3378,18 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int); extern int generic_check_addressable(unsigned, u64); +#ifdef CONFIG_UNICODE +extern int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str); +extern int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, + const char *str, const struct qstr *name); +extern bool needs_casefold(const struct inode *dir); +#else +static inline bool needs_casefold(const struct inode *dir) +{ + return false; +} +#endif + #ifdef CONFIG_MIGRATION extern int buffer_migrate_page(struct address_space *, struct page *, struct page *, -- 2.25.1.481.gfbce0eb801-goog