From patchwork Tue Sep 13 23:41:45 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: 1677569 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org (client-ip=2404:9400:2221:ea00::3; helo=gandalf.ozlabs.org; envelope-from=srs0=vkve=zq=vger.kernel.org=linux-ext4-owner@ozlabs.org; receiver=) Authentication-Results: legolas.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=EpkBrvHT; 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 ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4MS0PN24nfz1ypW for ; Wed, 14 Sep 2022 09:42:16 +1000 (AEST) Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4MS0PN1yGBz4xD1 for ; Wed, 14 Sep 2022 09:42:16 +1000 (AEST) Received: by gandalf.ozlabs.org (Postfix) id 4MS0PN1w0zz4xFt; Wed, 14 Sep 2022 09:42:16 +1000 (AEST) Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: gandalf.ozlabs.org; dmarc=pass (p=none dis=none) header.from=collabora.com 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=EpkBrvHT; 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 4MS0PN1qycz4xD1 for ; Wed, 14 Sep 2022 09:42:16 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229604AbiIMXmP (ORCPT ); Tue, 13 Sep 2022 19:42:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229607AbiIMXmN (ORCPT ); Tue, 13 Sep 2022 19:42:13 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7821A3ECE3 for ; Tue, 13 Sep 2022 16:42:12 -0700 (PDT) Received: from localhost (modemcable141.102-20-96.mc.videotron.ca [96.20.102.141]) (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: krisman) by madras.collabora.co.uk (Postfix) with ESMTPSA id 1A8FF6602016; Wed, 14 Sep 2022 00:42:11 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1663112531; bh=x39ZcEhRwiM4U+9tKyLLHn9zRo5lbo5kmdkjrz5b9hQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EpkBrvHTlIO3439qRYGUGsn+blrzZ79XMBphODuCEqV/8c5n6j2SPQnbjHLs7GKKf QiyZpdV042PDDnT9/Ml62ZMeb2toG0655PiE929xJmHnEr681YQRpPT+mY/lAmF7FL MHa3ZPSN7s1yoSB+aWzc38hZSRDnbNuF4dgV3578eEsl8vcCJDvPMUwA9M8JZt5XwH xAIbJ1A6JBMZDBc5mpjsCfMHVYu+42/LU1FE2X1Hc+h7lSfaeQtNsoDnCoLXGeRf+N Dm5cZH2fOnEgq7fHxdnpX8EStAA7NV0i+tgYlshxmapXXzS266YDuyCPvqlb2rcC5n duX/P/5oxvF9Q== 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, Eric Biggers Subject: [PATCH v9 3/8] libfs: Introduce case-insensitive string comparison helper Date: Tue, 13 Sep 2022 19:41:45 -0400 Message-Id: <20220913234150.513075-4-krisman@collabora.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220913234150.513075-1-krisman@collabora.com> References: <20220913234150.513075-1-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_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE 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. Reviewed-by: Eric Biggers Signed-off-by: Gabriel Krisman Bertazi --- 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 31b0ddf01c31..f8f95e2f13c1 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1454,6 +1454,74 @@ 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) 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 9eced4cc286e..d43178edb3d5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3352,6 +3352,10 @@ 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); int may_setattr(struct user_namespace *mnt_userns, struct inode *inode, unsigned int ia_valid);