From patchwork Thu Jan 4 20:55:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13511533 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 06A90225CC; Thu, 4 Jan 2024 20:55:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OqA/BUsK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFAFDC433C8; Thu, 4 Jan 2024 20:55:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704401735; bh=1r06tXm8NgOA5sTI/NY3+FnaN5Z36M20RW2wBfWvLiA=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=OqA/BUsKZsuAMT1X25W0czBvNy3Pv0P8qJS4Dn74fP1ZtTOlrUwfD0rGQQ08JIJeV 1mPwHAX1GxLCfX5Wlu0bn0NIE9ElcYoiQslOw72fRkqxomi0aKmNLBWo+MyT4NWeRD j+aB9JbmETGmZ7zK2OUX0SF29BBd9roxyeVBwuLvRzlHRE3c2TuSYcBerrJ4Ba1Th0 yyS23rnGoLclz4BkQryMPFe97V/L2gdAjjSwocg7/u9bFkiyp4JzGZ+oILGTnz4HlY NB9c4Xsc0gPmZPWmaBIYCaABLDbuzt57CIR9oogT6IG8O8Uai6o4GjnfzckMp16qUL HsniQUXbxeWfQ== Subject: [PATCH v4 2/2] fs: Create a generic is_dot_dotdot() utility From: Chuck Lever To: jlayton@redhat.com, amir73il@gmail.com Cc: Jeff Layton , Chuck Lever , linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, trondmy@hammerspace.com, viro@zeniv.linux.org.uk, brauner@kernel.org Date: Thu, 04 Jan 2024 15:55:33 -0500 Message-ID: <170440173389.204613.14502976575665083984.stgit@bazille.1015granger.net> In-Reply-To: <170440153940.204613.6839922871340228115.stgit@bazille.1015granger.net> References: <170440153940.204613.6839922871340228115.stgit@bazille.1015granger.net> User-Agent: StGit/1.5 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Chuck Lever De-duplicate the same functionality in several places by hoisting the is_dot_dotdot() utility function into linux/fs.h. Suggested-by: Amir Goldstein Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Reviewed-by: Amir Goldstein --- fs/crypto/fname.c | 8 +------- fs/ecryptfs/crypto.c | 10 ---------- fs/exportfs/expfs.c | 4 +--- fs/f2fs/f2fs.h | 11 ----------- fs/namei.c | 6 ++---- include/linux/fs.h | 13 +++++++++++++ 6 files changed, 17 insertions(+), 35 deletions(-) diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 7b3fc189593a..0ad52fbe51c9 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -74,13 +74,7 @@ struct fscrypt_nokey_name { static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) { - if (str->len == 1 && str->name[0] == '.') - return true; - - if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.') - return true; - - return false; + return is_dot_dotdot(str->name, str->len); } /** diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index 03bd55069d86..2fe0f3af1a08 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1949,16 +1949,6 @@ int ecryptfs_encrypt_and_encode_filename( return rc; } -static bool is_dot_dotdot(const char *name, size_t name_size) -{ - if (name_size == 1 && name[0] == '.') - return true; - else if (name_size == 2 && name[0] == '.' && name[1] == '.') - return true; - - return false; -} - /** * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext * @plaintext_name: The plaintext name diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 84af58eaf2ca..07ea3d62b298 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -255,9 +255,7 @@ static bool filldir_one(struct dir_context *ctx, const char *name, int len, container_of(ctx, struct getdents_callback, ctx); buf->sequence++; - /* Ignore the '.' and '..' entries */ - if ((len > 2 || name[0] != '.' || (len == 2 && name[1] != '.')) && - buf->ino == ino && len <= NAME_MAX) { + if (buf->ino == ino && len <= NAME_MAX && !is_dot_dotdot(name, len)) { memcpy(buf->name, name, len); buf->name[len] = '\0'; buf->found = 1; diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 9043cedfa12b..322a3b8a3533 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -3368,17 +3368,6 @@ static inline bool f2fs_cp_error(struct f2fs_sb_info *sbi) return is_set_ckpt_flags(sbi, CP_ERROR_FLAG); } -static inline bool is_dot_dotdot(const u8 *name, size_t len) -{ - if (len == 1 && name[0] == '.') - return true; - - if (len == 2 && name[0] == '.' && name[1] == '.') - return true; - - return false; -} - static inline void *f2fs_kmalloc(struct f2fs_sb_info *sbi, size_t size, gfp_t flags) { diff --git a/fs/namei.c b/fs/namei.c index 71c13b2990b4..2386a70667fa 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2667,10 +2667,8 @@ static int lookup_one_common(struct mnt_idmap *idmap, if (!len) return -EACCES; - if (unlikely(name[0] == '.')) { - if (len < 2 || (len == 2 && name[1] == '.')) - return -EACCES; - } + if (is_dot_dotdot(name, len)) + return -EACCES; while (len--) { unsigned int c = *(const unsigned char *)name++; diff --git a/include/linux/fs.h b/include/linux/fs.h index 98b7a7a8c42e..53dd58a907e0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2846,6 +2846,19 @@ extern bool path_is_under(const struct path *, const struct path *); extern char *file_path(struct file *, char *, int); +/** + * is_dot_dotdot - returns true only if @name is "." or ".." + * @name: file name to check + * @len: length of file name, in bytes + * + * Coded for efficiency. + */ +static inline bool is_dot_dotdot(const char *name, size_t len) +{ + return len && unlikely(name[0] == '.') && + (len < 2 || (len == 2 && name[1] == '.')); +} + #include /* needed for stackable file system support */