From patchwork Thu Feb 15 04:26:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eugen Hristev X-Patchwork-Id: 13557356 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 lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 83816C4829E for ; Thu, 15 Feb 2024 04:27:42 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1raTLZ-0000XZ-8m; Thu, 15 Feb 2024 04:27:41 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1raTLX-0000XK-V4 for linux-f2fs-devel@lists.sourceforge.net; Thu, 15 Feb 2024 04:27:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=Cy7z8H89MBnBLftUZQrp7nu413Jc4ar7/bv2lhOC8fs=; b=ba/4557Kxa7lHfsPjRSmdY1lSd UKTfs9hZ0pkeanw/msPm9cBOJzDSrrDDBD1p3r+sZbbBUszmontO2lHrhMWNPUDUSNwqlnCR6/6c8 gY4gIkmO8djlk6EOdn6xLZAx1ZGAU17IVRlEzl4vT/Ce8N9G1vhU1t2gZJNos/RvYmFE=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=Cy7z8H89MBnBLftUZQrp7nu413Jc4ar7/bv2lhOC8fs=; b=nOXXSmBcQaDtAutUkjfEw3kN04 RSG664HWNmz466CjQoj+b6xh3LJmjJHdFbyzenkARe1cZ9ionHmDOH/JhfOxE5dkBuM1Lz8Hv5qSD iKEVKvIg7x5RVYCSXWHRV+PHY0fzLOXTxBjbjQSGdcTWMfBODKlqJ1TITxwureC9zwIQ=; Received: from madrid.collaboradmins.com ([46.235.227.194]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1raTLW-0004ou-Ss for linux-f2fs-devel@lists.sourceforge.net; Thu, 15 Feb 2024 04:27:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1707971248; bh=r5QM4nGPXD+IG/Bct8X4+GkfjZyg/HCZtSD4LIsBnEc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tMJWb7BMFdao+VV4nV9uZIBpFJ5phgAwsjo6d7Y6Ujgyw9ncKgrK5+Elp7PfNCZJT +vyg6DbjswL3ftJKtxcmiFaEG/S3TgvAyqX0tl2oY4SgjYa6WY+kdqgJkDyubv+Ns2 J7qjICakRpCVQ8zo5D2AHp7X5gftjEUNaVwtvLne3mBza5bi4eXJSJxE1cOdHUc/l5 SVVQ2edV72fT4N0yzkuGcva7B/UGf+Ud+HNqut1dqpb3V2mETmaSg5HSovzphhBDIk vZFr5w01A3haM29wPsPL1XruqbwZ5hOJOLIEZaxN4m9bkhDPXMPPRVYCqVvamw65CU x8pY1wVJrweVQ== Received: from eugen-station.. (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: ehristev) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 891BE378208E; Thu, 15 Feb 2024 04:27:23 +0000 (UTC) To: tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, jaegeuk@kernel.org, chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org Date: Thu, 15 Feb 2024 06:26:49 +0200 Message-Id: <20240215042654.359210-4-eugen.hristev@collabora.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240215042654.359210-1-eugen.hristev@collabora.com> References: <20240215042654.359210-1-eugen.hristev@collabora.com> MIME-Version: 1.0 X-Headers-End: 1raTLW-0004ou-Ss Subject: [f2fs-dev] [PATCH v10 3/8] libfs: Introduce case-insensitive string comparison helper X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Eugen Hristev via Linux-f2fs-devel From: Eugen Hristev Reply-To: Eugen Hristev Cc: krisman@suse.de, brauner@kernel.org, jack@suse.cz, linux-kernel@vger.kernel.org, eugen.hristev@collabora.com, viro@zeniv.linux.org.uk, kernel@collabora.com, Gabriel Krisman Bertazi Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net From: Gabriel Krisman Bertazi 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 [eugen.hristev@collabora.com: rework to first test the exact match] Signed-off-by: Eugen Hristev --- fs/libfs.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 4 +++ 2 files changed, 84 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index bb18884ff20e..82871fa1b066 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1773,6 +1773,86 @@ 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) with a dirent. + * This is a filesystem helper for comparison with directory entries. + * generic_ci_d_compare should be used in VFS' ->d_compare instead. + * + * @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, u32 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 res; + + if (IS_ENCRYPTED(parent)) { + const struct fscrypt_str encrypted_name = + FSTR_INIT((u8 *) de_name, de_name_len); + + if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent))) + return -EINVAL; + + decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); + if (!decrypted_name.name) + return -ENOMEM; + res = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, + &decrypted_name); + if (res < 0) + goto out; + dirent.name = decrypted_name.name; + dirent.len = decrypted_name.len; + } + + /* + * Attempt a case-sensitive match first. It is cheaper and + * should cover most lookups, including all the sane + * applications that expect a case-sensitive filesystem. + * + * This comparison is safe under RCU because the caller + * guarantees the consistency between str and len. See + * __d_lookup_rcu_op_compare() for details. + */ + if (folded_name->name) { + if (dirent.len == folded_name->len && + !memcmp(folded_name->name, dirent.name, dirent.len)) { + res = 1; + goto out; + } + res = !utf8_strncasecmp_folded(um, folded_name, &dirent); + } else { + if (dirent.len == name->len && + !memcmp(name->name, dirent.name, dirent.len) && + (!sb_has_strict_encoding(sb) || !utf8_validate(um, name))) { + res = 1; + goto out; + } + res = !utf8_strncasecmp(um, name, &dirent); + } + +out: + kfree(decrypted_name.name); + return res; +} +EXPORT_SYMBOL(generic_ci_match); #endif #ifdef CONFIG_FS_ENCRYPTION diff --git a/include/linux/fs.h b/include/linux/fs.h index 820b93b2917f..7af691ff8d44 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3296,6 +3296,10 @@ 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, u32 de_name_len); static inline bool sb_has_encoding(const struct super_block *sb) {