From patchwork Thu Jun 6 07:33:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eugen Hristev X-Patchwork-Id: 13687932 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0D3D313C80F; Thu, 6 Jun 2024 07:34:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.235.227.194 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717659281; cv=none; b=Hd15gia8T2hDZ++69Jei8C1F9j7ZgN2C2jWiOjYOgHjBuYE4OVQigBCE9ifoY/1RtGMTc79d6o81nFk/koStUGaXmdOSSglEZb2Bfi0kyIkt7k+89aQmqfrnwAAnF0N2EjqCrr1aRyia4Q+6DOz17iRlEXH9V36ChgJsxQ4lg+A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717659281; c=relaxed/simple; bh=k2lM/43/rKq0SBXPEuuWsOvKQDRgGSdsJNLUcoGSQAk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=fR5zSvYLjzR9s6WwxhU7Heus7mMa1NFEMylIlYYwCAO3B0B7uOsy6QdZoHGw5F8hBpqj7uoqaWSpb7aAmolkqWt6G1iUx+wWlpSaN8OpEAC9FXda8mP/xvfCaGfoUuisVHuIdt5uwbG3Gnc87elFBy8wm43JfWAoDr4P1uzDxzQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=Bwk759Hg; arc=none smtp.client-ip=46.235.227.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="Bwk759Hg" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1717659278; bh=k2lM/43/rKq0SBXPEuuWsOvKQDRgGSdsJNLUcoGSQAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bwk759Hgvf6pJ0JDfaJ160yU1e/Ss5JUWAja70s0ShWdkVC9PUbBxMCINfP4Myiiq rm399mv27ekOXn+qCPtmZku1SCJLW8NrrxCGi5eJ4DobkE9ekAIhEvmPEiiv2GcwCU KhjHmWF8DLNhoQjf3wb54xqNLVKfLavwrl9klOeCyBTak9md39qNrdfD+tM3nHJfEV fUm3CJzsjCzeocrXduuqS/6Y519NkO2c6/JGOiVMYTHMlTlw5GT0L6j/VKz07Z9uV3 9Cwq6HxfDJNrBET59yinZnAUlf+16mQpvjKVYWTpnG8zfzMbBt6nC0HWaxJPsiAuYF F6HjLy7IEyw6g== 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 3CE2E37821D7; Thu, 6 Jun 2024 07:34:37 +0000 (UTC) From: Eugen Hristev To: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, jaegeuk@kernel.org, adilger.kernel@dilger.ca, tytso@mit.edu Cc: chao@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, ebiggers@google.com, krisman@suse.de, kernel@collabora.com, Gabriel Krisman Bertazi , Eugen Hristev Subject: [PATCH v18 3/7] libfs: Introduce case-insensitive string comparison helper Date: Thu, 6 Jun 2024 10:33:49 +0300 Message-Id: <20240606073353.47130-4-eugen.hristev@collabora.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240606073353.47130-1-eugen.hristev@collabora.com> References: <20240606073353.47130-1-eugen.hristev@collabora.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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, cleanup and add error message] Signed-off-by: Eugen Hristev --- fs/libfs.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 4 +++ 2 files changed, 78 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index b635ee5adbcc..8aa34870449f 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1854,6 +1854,80 @@ static const struct dentry_operations generic_ci_dentry_ops = { .d_revalidate = fscrypt_d_revalidate, #endif }; + +/** + * 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 = 0; + + 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) { + kfree(decrypted_name.name); + return res; + } + 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. + */ + + if (dirent.len == name->len && + !memcmp(name->name, dirent.name, dirent.len)) + goto out; + + if (folded_name->name) + res = utf8_strncasecmp_folded(um, folded_name, &dirent); + else + res = utf8_strncasecmp(um, name, &dirent); + +out: + kfree(decrypted_name.name); + if (res < 0 && sb_has_strict_encoding(sb)) { + pr_err_ratelimited("Directory contains filename that is invalid UTF-8"); + return 0; + } + 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 639885621608..f8ca264a0edc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3367,6 +3367,10 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int); extern int generic_check_addressable(unsigned, u64); extern void generic_set_sb_d_ops(struct super_block *sb); +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) {