From patchwork Thu May 19 01:40:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 1633035 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.a=rsa-sha256 header.s=mail header.b=GSqGnV8X; dkim-atps=neutral Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4L3XdF5rNdz9tlf for ; Thu, 19 May 2022 11:41:21 +1000 (AEST) Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4L3XdF59zWz4xbC for ; Thu, 19 May 2022 11:41:21 +1000 (AEST) Received: by gandalf.ozlabs.org (Postfix) id 4L3XdF53B3z4xc1; Thu, 19 May 2022 11:41:21 +1000 (AEST) Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: gandalf.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: gandalf.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.a=rsa-sha256 header.s=mail header.b=GSqGnV8X; dkim-atps=neutral Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4L3XdF4z9Bz4xbC for ; Thu, 19 May 2022 11:41:21 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232528AbiESBlT (ORCPT ); Wed, 18 May 2022 21:41:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232555AbiESBlQ (ORCPT ); Wed, 18 May 2022 21:41:16 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72BA24664E for ; Wed, 18 May 2022 18:41:12 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id C63D41F45432 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1652924471; bh=wyagYd5Dfkrnqof9rQ2CUhebuwYOsCzc1nWjWy4XPaA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GSqGnV8XXZ30l9sip2sf30tHHQx0++7avmwOAUkmbn4sDFtfhiUEuSEhUlSfRY0RT dDgkocCAHfcB4PSBxdz74YvHambOArPfKbJghGblA+XgLuPHrV9NuzyV3TULTQDjym WfxrPWKCco9nSLPlEGV0SoemPqeQq7tlcp5oItslpBbpPc9PEcuN8HJAeYpDIrRQXB Wt/XtPiikii2ULDD5CydJ4UPiiVj8D7ke3B/fTd80gxkzOPcnE7ZN70KAbuDnoake6 TVXEpvsNTYEtkccp5uOpEefJ5MbhfqUjCRUA6+LSDouYmK6c8pQHgnTLdpFxDBWQEF 3VdU3B/obCAPQ== 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 v6 3/8] libfs: Introduce case-insensitive string comparison helper Date: Wed, 18 May 2022 21:40:39 -0400 Message-Id: <20220519014044.508099-4-krisman@collabora.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220519014044.508099-1-krisman@collabora.com> References: <20220519014044.508099-1-krisman@collabora.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE,UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net 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 Reviewed-by: Eric Biggers --- Changes since v5: (eric) - Rename variable err -> res - Retype de_name_len from size_t to u32 - Bring WARN_ON_ONCE(!fscrypt_has_encryption_key) from f2fs implementation --- fs/libfs.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 4 +++ 2 files changed, 72 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index 974125270a42..c8f40ee35743 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1465,6 +1465,74 @@ 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, 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, match = false; + + 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; + } + + if (folded_name->name) + res = utf8_strncasecmp_folded(um, folded_name, &dirent); + else + res = utf8_strncasecmp(um, name, &dirent); + + if (!res) + match = true; + else if (res < 0 && !sb_has_strict_encoding(sb)) { + /* + * In non-strict mode, fallback to a byte comparison if + * the names have invalid characters. + */ + res = 0; + match = ((name->len == dirent.len) && + !memcmp(name->name, dirent.name, dirent.len)); + } + +out: + kfree(decrypted_name.name); + return (res >= 0) ? match : res; +} +EXPORT_SYMBOL(generic_ci_match); #endif #ifdef CONFIG_FS_ENCRYPTION diff --git a/include/linux/fs.h b/include/linux/fs.h index e2d892b201b0..4c2b781f667a 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, u32 de_name_len); #ifdef CONFIG_MIGRATION extern int buffer_migrate_page(struct address_space *,