From patchwork Thu Jan 4 20:55:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13511532 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 2365C28E0D; Thu, 4 Jan 2024 20:55:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ayZbPGPX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E415CC433C7; Thu, 4 Jan 2024 20:55:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704401728; bh=IhnX4hHtRzrAnyp6d66bwgBG87Kr2elb7Rz8vNJe5Ow=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=ayZbPGPXvWqfwtKSX6X6zZI6EM26dV4fn+554cr4go09tYn7hraciFC2IEqAeHdnt PhOVm3pZa/454HgW27ta0+Cm80OymPFAvCKIU67zPJO4OeAgwNfx7b1xgKaQj/48v2 VA49/FxsiLlkvEOWcBKiy1MIX3+OkAim38jhMHb6oPw94H86P1VEEpIwk0weE1UwWS FLYTWtZwAxfPO6T5Dhg3FZ9vChnYvA02tSmpk26GUflJs0VUfLitI21hhC+zATw/20 3DWiL+Ik52X+Cwywso/wzSK2Yrmg3Tkaqu5AUSmKnFye9PTOw2S+WAOFz2NdgNuBFf laREqoye1Ld7A== Subject: [PATCH v4 1/2] exportfs: fix the fallback implementation of the get_name export operation From: Chuck Lever To: jlayton@redhat.com, amir73il@gmail.com Cc: Trond Myklebust , 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 15:55:26 -0500 Message-ID: <170440172682.204613.14380981758225537964.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: Trond Myklebust The fallback implementation for the get_name export operation uses readdir() to try to match the inode number to a filename. That filename is then used together with lookup_one() to produce a dentry. A problem arises when we match the '.' or '..' entries, since that causes lookup_one() to fail. This has sometimes been seen to occur for filesystems that violate POSIX requirements around uniqueness of inode numbers, something that is common for snapshot directories. This patch just ensures that we skip '.' and '..' rather than allowing a match. Signed-off-by: Trond Myklebust Reviewed-by: Jeff Layton Acked-by: Amir Goldstein Link: https://lore.kernel.org/linux-nfs/CAOQ4uxiOZobN76OKB-VBNXWeFKVwLW_eK5QtthGyYzWU9mjb7Q@mail.gmail.com/ Signed-off-by: Chuck Lever --- fs/exportfs/expfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 3ae0154c5680..84af58eaf2ca 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -255,7 +255,9 @@ static bool filldir_one(struct dir_context *ctx, const char *name, int len, container_of(ctx, struct getdents_callback, ctx); buf->sequence++; - if (buf->ino == ino && len <= NAME_MAX) { + /* Ignore the '.' and '..' entries */ + if ((len > 2 || name[0] != '.' || (len == 2 && name[1] != '.')) && + buf->ino == ino && len <= NAME_MAX) { memcpy(buf->name, name, len); buf->name[len] = '\0'; buf->found = 1; 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 */