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=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 5D905C282CE for ; Mon, 8 Apr 2019 08:50:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E57120880 for ; Mon, 8 Apr 2019 08:50:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RqXWXhcR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726642AbfDHIu0 (ORCPT ); Mon, 8 Apr 2019 04:50:26 -0400 Received: from mail-oi1-f201.google.com ([209.85.167.201]:40427 "EHLO mail-oi1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725854AbfDHIu0 (ORCPT ); Mon, 8 Apr 2019 04:50:26 -0400 Received: by mail-oi1-f201.google.com with SMTP id q82so5376633oif.7 for ; Mon, 08 Apr 2019 01:50:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=y7S9KFvwD3SI2JYMueM0A4SKJSx0WkTCQJ8CcpYn5Kg=; b=RqXWXhcR2Y75mafYXNTn5qoRi6apbyTpTCqT8c5zrVG4+46ZoFHUYCScyunNOI+nP/ jDFWd6R7zCBQlHGB2TGsg5movD72iMuIMLvfx4zqiI8RXxl2UJ8ugPHBDzYuXZB5MerG 5yApR+49mf1hUytWlJ1uH9Nv0bbBu8hWuepSmOuZjEIYoeiD2WB4UlVoqfw6k6/C/8kq +iErTL6355qg+QAyL4iY90SR9b8yDVVU5c/t6bhjxwCWbo9KWovJvNlg9FaTGrjBYzD/ ZNEPWin0XgwdPVDWip7L4orXzUi9GvlMrJXkIdUW9nPt4oB0We5+j8Qjx1cECt//IAup k2Cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=y7S9KFvwD3SI2JYMueM0A4SKJSx0WkTCQJ8CcpYn5Kg=; b=n1WQz1qUvPQabTBwSWmuIMAPQdffhVUlGpOsmQ8BufBwv7DzPM/ujr9HPaXjJ9Zf/o waL8/mDAj2DQoDKRYh9jCpHC5oAeslE1qXkHrxe30ZZdgpuD8J8u1iV4Z5/sC+jjInJL vSASga0sLDGCAcIruE/9efX+xDyf1UP6aA9Jt3Of/YPH3li87VcDCNj7Xn38Aw1bmzdQ Q4i1bNA2v3ZexzX8T09fihg93n2RU668CytBcd7+LHNpOd8S12kK80LMkJT7YuFuo9C0 ts7jC1Tsl0+t6zFjPcccd2WVGmBcqvV8jkuGdp21SiUoJBlFtwDKCr0mnqHFE/Pj2xMx lw3A== X-Gm-Message-State: APjAAAU/n0FXooCjYxjKMs7ekoTZIZfRsIRB9SIZcBJEQoe8ipJTlOG3 x/qSbrrXnJYZd+DFgFwFLdM4s/UQJ+Qqc6kRm+A= X-Google-Smtp-Source: APXvYqykmZlVR4gPI6+41B5wJsAKNia6wzbN5CQv5lpdF6XNImJvkF7nMQgKAAMb2ZV106za6+jPX6TmR02wARHqZrY= X-Received: by 2002:aca:b887:: with SMTP id i129mr2265515oif.47.1554713421813; Mon, 08 Apr 2019 01:50:21 -0700 (PDT) Date: Mon, 8 Apr 2019 16:50:16 +0800 Message-Id: <20190408085016.13042-1-huangrandall@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH] f2fs: fix to avoid accessing xattr across the boundary From: Randall Huang To: jaegeuk@kernel.org, yuchao0@huawei.com, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Cc: huangrandall@google.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we traverse xattr entries via __find_xattr(), if the raw filesystem content is faked or any hardware failure occurs, out-of-bound error can be detected by KASAN. Fix the issue by introducing boundary check. [ 38.402878] c7 1827 BUG: KASAN: slab-out-of-bounds in f2fs_getxattr+0x518/0x68c [ 38.402891] c7 1827 Read of size 4 at addr ffffffc0b6fb35dc by task [ 38.402935] c7 1827 Call trace: [ 38.402952] c7 1827 [] dump_backtrace+0x0/0x6bc [ 38.402966] c7 1827 [] show_stack+0x20/0x2c [ 38.402981] c7 1827 [] dump_stack+0xfc/0x140 [ 38.402995] c7 1827 [] print_address_description+0x80/0x2d8 [ 38.403009] c7 1827 [] kasan_report_error+0x198/0x1fc [ 38.403022] c7 1827 [] kasan_report_error+0x0/0x1fc [ 38.403037] c7 1827 [] __asan_load4+0x1b0/0x1b8 [ 38.403051] c7 1827 [] f2fs_getxattr+0x518/0x68c [ 38.403066] c7 1827 [] f2fs_xattr_generic_get+0xb0/0xd0 [ 38.403080] c7 1827 [] __vfs_getxattr+0x1f4/0x1fc [ 38.403096] c7 1827 [] inode_doinit_with_dentry+0x360/0x938 [ 38.403109] c7 1827 [] selinux_d_instantiate+0x2c/0x38 [ 38.403123] c7 1827 [] security_d_instantiate+0x68/0x98 [ 38.403136] c7 1827 [] d_splice_alias+0x58/0x348 [ 38.403149] c7 1827 [] f2fs_lookup+0x608/0x774 [ 38.403163] c7 1827 [] lookup_slow+0x1e0/0x2cc [ 38.403177] c7 1827 [] walk_component+0x160/0x520 [ 38.403190] c7 1827 [] path_lookupat+0x110/0x2b4 [ 38.403203] c7 1827 [] filename_lookup+0x1d8/0x3a8 [ 38.403216] c7 1827 [] user_path_at_empty+0x54/0x68 [ 38.403229] c7 1827 [] SyS_getxattr+0xb4/0x18c [ 38.403241] c7 1827 [] el0_svc_naked+0x34/0x38 Bug: 126558260 Signed-off-by: Randall Huang --- fs/f2fs/xattr.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 848a785abe25..0531c1e38275 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -202,12 +202,17 @@ static inline const struct xattr_handler *f2fs_xattr_handler(int index) return handler; } -static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index, - size_t len, const char *name) +static struct f2fs_xattr_entry *__find_xattr(void *base_addr, + int base_addr_limit, int index, + size_t len, const char *name) { struct f2fs_xattr_entry *entry; + void *max_addr = base_addr + ENTRY_SIZE(XATTR_ENTRY(base_addr)) + + base_addr_limit - 1; list_for_each_xattr(entry, base_addr) { + if ((void *)entry + sizeof(__u32) > max_addr) + return NULL; if (entry->e_name_index != index) continue; if (entry->e_name_len != len) @@ -337,9 +342,9 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage, else cur_addr = txattr_addr; - *xe = __find_xattr(cur_addr, index, len, name); + *xe = __find_xattr(cur_addr, XATTR_PADDING_SIZE, index, len, name); check: - if (IS_XATTR_LAST_ENTRY(*xe)) { + if (!*xe || IS_XATTR_LAST_ENTRY(*xe)) { err = -ENODATA; goto out; } @@ -606,9 +611,14 @@ static int __f2fs_setxattr(struct inode *inode, int index, return error; /* find entry with wanted name. */ - here = __find_xattr(base_addr, index, len, name); + here = __find_xattr(base_addr, inline_xattr_size(inode) + + VALID_XATTR_BLOCK_SIZE + XATTR_PADDING_SIZE, + index, len, name); - found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1; + if (!here) + found = 0; + else + found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1; if (found) { if ((flags & XATTR_CREATE)) { -- 2.21.0.392.gf8f6787159e-goog