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,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 7F917C433B4 for ; Mon, 19 Apr 2021 20:48:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 613936135F for ; Mon, 19 Apr 2021 20:48:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243218AbhDSUtU (ORCPT ); Mon, 19 Apr 2021 16:49:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:54550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240991AbhDSUq2 (ORCPT ); Mon, 19 Apr 2021 16:46:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9296D613E6; Mon, 19 Apr 2021 20:45:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618865116; bh=56K4myA+5ARz3MjMb1LaGidGUwu2AMF8u76s8So379w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lu51eshk1kvOrgbzg6AOjh4YLCkZ0rP5AxwVla+9Uyzm4zlGKtM1iBak+sg0QfNRu mvhXbLa2EdxFht0vGoFF709OGunjkscn4greBYNA/JwPehBUISmxpc9WcPCCpk78jR D0ckaBw1/AjiPAHo0mVr9NcjYvTkdKJd+XYsjkDrNkm6v6hheMiCXpgLWtOX/WNMf9 gdUTvOAg95zrUprKFAJNT3/dHUC0xPIimMrnx/d9kh4GkJ5WSak/RLK/Ksg97j25UZ TaE/Q3+wQc2Ja02rF5IWlxzOexJDaS29P9usmy02nV2JaUo484VJGFFzcT5NdgsX+R Ad1khHcKTpZqQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Linus Torvalds , Al Viro , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 14/14] readdir: make sure to verify directory entry for legacy interfaces too Date: Mon, 19 Apr 2021 16:44:54 -0400 Message-Id: <20210419204454.6601-14-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210419204454.6601-1-sashal@kernel.org> References: <20210419204454.6601-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds [ Upstream commit 0c93ac69407d63a85be0129aa55ffaec27ffebd3 ] 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: Sasha Levin --- fs/readdir.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/readdir.c b/fs/readdir.c index de2eceffdee8..07a3b5baa404 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -150,6 +150,9 @@ static int fillonedir(struct dir_context *ctx, const char *name, int namlen, 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; @@ -417,6 +420,9 @@ static int compat_fillonedir(struct dir_context *ctx, const char *name, 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; -- 2.30.2