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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5418C433EF for ; Wed, 18 May 2022 17:23:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240975AbiERRXo (ORCPT ); Wed, 18 May 2022 13:23:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240967AbiERRXl (ORCPT ); Wed, 18 May 2022 13:23:41 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1CE519CEC4 for ; Wed, 18 May 2022 10:23:40 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 99F591F454A9 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1652894619; bh=9dMAdB9y4g6zgj/AoLBzcTKL80b5leplN1sb+guWwX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YLbzd4A2Zhjzif5lpNaqhUgLqEhaqFaNtQXNdQow8lskFH0cIb/2eKgMQnKjy5WYn vQ/AR2+nMKFcMJrFJEGehwAktMy1/t9HdJ4ilXm49hyWtb2FcLsywODiiL6kDmiZVV +dYsPdwT5jhm9Cyb0EeOB4MS2yvCJ7sGxYziZsAdQgBgIhhFq8PlHX/K3sfwk7DUgh GiHSB0XhyDZjzB0zaAfUjE7g0UsLi/GD9WJ+V4ezrD1jXayz5iTYQXPzSCbciFDpN3 JogXp8s4zdv2emdsYusV/BmX9e4UBG7/TIyM1gMR7VYTXzZohude+nIPKuArWVwwQw HFIKX72yWOB0g== From: Gabriel Krisman Bertazi To: tytso@mit.edu, adilger.kernel@dilger.ca, jaegeuk@kernel.org, ebiggers@kernel.org Cc: linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Gabriel Krisman Bertazi , kernel@collabora.com Subject: [PATCH v5 3/8] libfs: Introduce case-insensitive string comparison helper Date: Wed, 18 May 2022 13:23:15 -0400 Message-Id: <20220518172320.333617-4-krisman@collabora.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220518172320.333617-1-krisman@collabora.com> References: <20220518172320.333617-1-krisman@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org generic_ci_match can be used by case-insensitive filesystems to compare strings under lookup with dirents in a case-insensitive way. This function is currently reimplemented by each filesystem supporting casefolding, so this reduces code duplication in filesystem-specific code. Signed-off-by: Gabriel Krisman Bertazi --- fs/libfs.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 4 +++ 2 files changed, 69 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index 974125270a42..6861d43563be 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1465,6 +1465,71 @@ static const struct dentry_operations generic_ci_dentry_ops = { .d_hash = generic_ci_d_hash, .d_compare = generic_ci_d_compare, }; + +/** + * generic_ci_match() - Match a name (case-insensitively) name with a dirent. + * @parent: Inode of the parent of the dirent under comparison + * @name: name under lookup. + * @folded_name: Optional pre-folded name under lookup + * @de_name: Dirent name. + * @de_name_len: dirent name length. + * + * + * Test whether a case-insensitive directory entry matches the filename + * being searched. If @folded_name is provided, it is used instead of + * recalculating the casefold of @name. + * + * Return: > 0 if the directory entry matches, 0 if it doesn't match, or + * < 0 on error. + */ +int generic_ci_match(const struct inode *parent, + const struct qstr *name, + const struct qstr *folded_name, + const u8 *de_name, size_t de_name_len) +{ + const struct super_block *sb = parent->i_sb; + const struct unicode_map *um = sb->s_encoding; + struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len); + struct qstr dirent = QSTR_INIT(de_name, de_name_len); + int err, match = false; + + if (IS_ENCRYPTED(parent)) { + const struct fscrypt_str encrypted_name = + FSTR_INIT((u8 *) de_name, de_name_len); + + decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); + if (!decrypted_name.name) + return -ENOMEM; + err = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, + &decrypted_name); + if (err < 0) + goto out; + dirent.name = decrypted_name.name; + dirent.len = decrypted_name.len; + } + + if (folded_name->name) + err = utf8_strncasecmp_folded(um, folded_name, &dirent); + else + err = utf8_strncasecmp(um, name, &dirent); + + if (!err) + match = true; + else if (err < 0 && !sb_has_strict_encoding(sb)) { + /* + * In non-strict mode, fallback to a byte comparison if + * the names have invalid characters. + */ + err = 0; + match = ((name->len == dirent.len) && + !memcmp(name->name, dirent.name, dirent.len)); + } + +out: + kfree(decrypted_name.name); + return (err >= 0) ? match : err; +} +EXPORT_SYMBOL(generic_ci_match); #endif #ifdef CONFIG_FS_ENCRYPTION diff --git a/include/linux/fs.h b/include/linux/fs.h index e2d892b201b0..7a0214bfac34 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3359,6 +3359,10 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int); extern int generic_check_addressable(unsigned, u64); extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry); +extern int generic_ci_match(const struct inode *parent, + const struct qstr *name, + const struct qstr *folded_name, + const u8 *de_name, size_t de_name_len); #ifdef CONFIG_MIGRATION extern int buffer_migrate_page(struct address_space *, -- 2.36.1