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=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 43AA3C4363D for ; Fri, 25 Sep 2020 17:14:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E850421741 for ; Fri, 25 Sep 2020 17:14:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601054081; bh=7c+/aUouCIhoN252DDnGiTWe7TCcYqeUOpv/kSATLnY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=zkgEqxUff9Clxi9nCK1LDxIG50IG2tmKj1Dn+FtDfETzguW+hRkGNmrNs2VfHcb/o T7CHQhFKulwWeGvnbrJjhvhMtVZQIVxPX2T2vmf8mEi9OP3fkKktejk62wyQUerJCi hhPj9S4FX8EivVHuaLyA1umcEAAFZ78i+ouGQYcw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729584AbgIYROj (ORCPT ); Fri, 25 Sep 2020 13:14:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:33864 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727402AbgIYROj (ORCPT ); Fri, 25 Sep 2020 13:14:39 -0400 Received: from gmail.com (unknown [104.132.1.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4EA1120936; Fri, 25 Sep 2020 17:14:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601054078; bh=7c+/aUouCIhoN252DDnGiTWe7TCcYqeUOpv/kSATLnY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pSPeDBr/ecinZYSW7vpLj0gvkqUSIwBNrJfA6D5cocctOSaQJjZyEB/SnvMKIBK4I KliHOxRuNSYe38uf9DFlJB1WISvWQsOuoed2WmFWztHS/IfWy0TNySvJ4KEeO75IuS rBTp4EZEJ1PoynYjx97qnevzUuIfetiQBwR7ew8s= Date: Fri, 25 Sep 2020 10:14:36 -0700 From: Eric Biggers To: Chao Yu Cc: jaegeuk@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: fix uninit-value in f2fs_lookup Message-ID: <20200925171436.GC3315208@gmail.com> References: <20200925151926.2658-1-chao@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200925151926.2658-1-chao@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 25, 2020 at 11:19:26PM +0800, Chao Yu wrote: > From: Chao Yu > > As syzbot reported: > > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x21c/0x280 lib/dump_stack.c:118 > kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122 > __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219 > f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503 > lookup_open fs/namei.c:3082 [inline] > open_last_lookups fs/namei.c:3177 [inline] > path_openat+0x2729/0x6a90 fs/namei.c:3365 > do_filp_open+0x2b8/0x710 fs/namei.c:3395 > do_sys_openat2+0xa88/0x1140 fs/open.c:1168 > do_sys_open fs/open.c:1184 [inline] > __do_compat_sys_openat fs/open.c:1242 [inline] > __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240 > __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240 > do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline] > __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139 > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162 > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205 > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c > > In f2fs_lookup(), @res_page could be used before being initialized, > because in __f2fs_find_entry(), once F2FS_I(dir)->i_current_depth was > been fuzzed to zero, then @res_page will never be initialized, causing > this kmsan warning, relocating @res_page initialization place to fix > this bug. > > Signed-off-by: Chao Yu > --- > fs/f2fs/dir.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c > index 703cf8e21fc0..83630341ffa3 100644 > --- a/fs/f2fs/dir.c > +++ b/fs/f2fs/dir.c > @@ -357,16 +357,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir, > unsigned int max_depth; > unsigned int level; > > + *res_page = NULL; > + > if (f2fs_has_inline_dentry(dir)) { > - *res_page = NULL; > de = f2fs_find_in_inline_dir(dir, fname, res_page); > goto out; > } > > - if (npages == 0) { > - *res_page = NULL; > + if (npages == 0) > goto out; > - } > > max_depth = F2FS_I(dir)->i_current_depth; > if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) { Can't the assignment to *res_page below be removed too? for (level = 0; level < max_depth; level++) { *res_page = NULL; de = find_in_level(dir, level, fname, res_page); if (de || IS_ERR(*res_page)) break; }