From patchwork Wed May 29 08:26:30 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eugen Hristev X-Patchwork-Id: 13678348 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 76D4C16C6A0; Wed, 29 May 2024 08:26:51 +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=1716971213; cv=none; b=G1GYqvNCXq+kGpbJFqCyxWij9Ip39DFDsb54JuVeY5sFYqiY6EXS/A3Ax34M2QdXsssST9UlVKcyy20ScB6hqq5DekPEXA/nYTKL5jwq3sq6wPkwJfrDvmIt9rH7KFjnECDa2skbLhiAz+ihzJK/6BwmM/ZlniAYLoqUByXlAz8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716971213; c=relaxed/simple; bh=ff8DpzwAZfEYeJk9vvRifefq2qMJjx4JWhXWjCFPTAA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=sspZqZGSpxAnsMvB54xu4dUNAWCi0kly9JNj8lwvrtxrE2urf3NE5dGbVf4bpHSYsnCo+jZga8k+9KuAh+yiw1EixpD2xhrRfiFIhGjh+K7JscnkFpIk+OUw4iXlGxxIqAGlQr4eQHE5T9k4tvHs4czws7bSmv4HzNu4BBwjLrg= 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=TgscUdLP; 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="TgscUdLP" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1716971209; bh=ff8DpzwAZfEYeJk9vvRifefq2qMJjx4JWhXWjCFPTAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TgscUdLPTsXKCd/PWwa9rhjQr2RlhAHZp/RKeQKh8bm7yk6+gS5aMrGWdE/OSQGgB f6YhJVLnCMscTqSMIs56F9K2lqjSbmVQ1RBnVgJTAru7MMTB2ncO0TPODrxEpmLuuT OgHu+LZ5hpVGGeAn4JjmAfQ4hdPff9EFMRQSoWGJWOYx9u6tmmMYbF/Iz+yuMh0g8E tAZCePmbKXC+9nHmDSWc9NuCq7gZszcOiK9ioE8PJ3vGS0YZhhJcrxokI/ZAa+N34m hmYKMvXMKvludVUSCQM3R2hpzdu2ReB2EVNzRvCUzlwyWK982qkGAoPD7bN9yo1BNT jmTeX8jVca0Fg== 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 B5C7D378216D; Wed, 29 May 2024 08:26:48 +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 v17 3/7] libfs: Introduce case-insensitive string comparison helper Date: Wed, 29 May 2024 11:26:30 +0300 Message-Id: <20240529082634.141286-4-eugen.hristev@collabora.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240529082634.141286-1-eugen.hristev@collabora.com> References: <20240529082634.141286-1-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..6a6cfa2d7d93 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 == (folded_name->name ? folded_name->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) {