From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_RED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C83CC4360C for ; Mon, 26 Apr 2021 07:39:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC91E61041 for ; Mon, 26 Apr 2021 07:39:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232710AbhDZHk0 (ORCPT ); Mon, 26 Apr 2021 03:40:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:50384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233127AbhDZHiw (ORCPT ); Mon, 26 Apr 2021 03:38:52 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0D1806023B; Mon, 26 Apr 2021 07:36:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1619422595; bh=Ddkc72Rss0ib0xj9rO9Ht1h1HUVwryqxPjuwiD2P51s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EpHBsOxCg1BI+e630OsXeeI0S+g8fBTIrkfxIcvx5dGpgGKi/OFTRiRFP1Wygqx3j nQRXyt7ZpATzBSExJ46V558SZrYbTMQpgtczDPxwnNGmpo5+0oDIP+nCQ1NVv90NNw 25HUFvY4GskTrvRdXZNXNfklF8L3d11d6GIYconc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro , Linus Torvalds Subject: [PATCH 4.19 27/57] readdir: make sure to verify directory entry for legacy interfaces too Date: Mon, 26 Apr 2021 09:29:24 +0200 Message-Id: <20210426072821.497562557@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210426072820.568997499@linuxfoundation.org> References: <20210426072820.568997499@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Linus Torvalds commit 0c93ac69407d63a85be0129aa55ffaec27ffebd3 upstream. This does the directory entry name verification for the legacy "fillonedir" (and compat) interface that goes all the way back to the dark ages before we had a proper dirent, and the readdir() system call returned just a single entry at a time. Nobody should use this interface unless you still have binaries from 1991, but let's do it right. This came up during discussions about unsafe_copy_to_user() and proper checking of all the inputs to it, as the networking layer is looking to use it in a few new places. So let's make sure the _old_ users do it all right and proper, before we add new ones. See also commit 8a23eb804ca4 ("Make filldir[64]() verify the directory entry filename is valid") which did the proper modern interfaces that people actually use. It had a note: Note that I didn't bother adding the checks to any legacy interfaces that nobody uses. which this now corrects. Note that we really don't care about POSIX and the presense of '/' in a directory entry, but verify_dirent_name() also ends up doing the proper name length verification which is what the input checking discussion was about. [ Another option would be to remove the support for this particular very old interface: any binaries that use it are likely a.out binaries, and they will no longer run anyway since we removed a.out binftm support in commit eac616557050 ("x86: Deprecate a.out support"). But I'm not sure which came first: getdents() or ELF support, so let's pretend somebody might still have a working binary that uses the legacy readdir() case.. ] Link: https://lore.kernel.org/lkml/CAHk-=wjbvzCAhAtvG0d81W5o0-KT5PPTHhfJ5ieDFq+bGtgOYg@mail.gmail.com/ Acked-by: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/readdir.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/readdir.c +++ b/fs/readdir.c @@ -132,6 +132,9 @@ static int fillonedir(struct dir_context if (buf->result) return -EINVAL; + buf->result = verify_dirent_name(name, namlen); + if (buf->result < 0) + return buf->result; d_ino = ino; if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { buf->result = -EOVERFLOW; @@ -398,6 +401,9 @@ static int compat_fillonedir(struct dir_ if (buf->result) return -EINVAL; + buf->result = verify_dirent_name(name, namlen); + if (buf->result < 0) + return buf->result; d_ino = ino; if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { buf->result = -EOVERFLOW;