From patchwork Wed Jan 3 15:19:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13510198 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 E42C31B279; Wed, 3 Jan 2024 15:19:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="plE6VWuw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD6CAC433C8; Wed, 3 Jan 2024 15:19:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704295179; bh=IhnX4hHtRzrAnyp6d66bwgBG87Kr2elb7Rz8vNJe5Ow=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=plE6VWuwt6yn2R19NJuwEhxEQ475wHEH7bMh1cK8HNRiLKQbsQKb2UYafOeBlVA8k +RPwQ0S69JONgea/v32RnpGSkgy1Gcm6URJgWqP6VPGeO8ahrhWqRcWZD5qbT9TuYm 1fESNLkXF39Hj5b5xbk5z5FrxsiMFoXNFeHNeip/ruF7U84ooIarcU9ShyfRgW5Gz1 +cqKK9HtkHjDyeeQNCdBYNsoE5bXEK50inR8yy82XNjNgYopamSoYNnI0X+SNj5/C7 edeN0J0cxrP4XwTsRaQisn7WPZA9YWRm2Rkz3+aBqFToJzlMUP1nuK7VeUSLhHxWod lVrRD+JRJCUZA== Subject: [PATCH v2 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: Wed, 03 Jan 2024 10:19:37 -0500 Message-ID: <170429517779.50646.9656897459585544068.stgit@bazille.1015granger.net> In-Reply-To: <170429478711.50646.12675561629884992953.stgit@bazille.1015granger.net> References: <170429478711.50646.12675561629884992953.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;