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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 6E90CC433DF for ; Mon, 18 May 2020 18:23:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DE1B20657 for ; Mon, 18 May 2020 18:23:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589826237; bh=depi0YMU8DCCn2TuI4u3Y9iUeIBgJt6Xy/R+eTHRwjA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=evOT2G4fVoaBKqoMdqxjlhKhqVzGG3vjy0Rw5G7CHxggqf8+Dgwy98nUjnJl4T8Wb NVYvICOp8DkWZe9UKrQBjq9xyvtYntxpGolr2lvQ3B6V9WmCpovR4X9NbhkjuCJCrm Vx943PJJ/Xe3nY/A03bz27FuaLP6zh1LQRrmVpX0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387879AbgERSX4 (ORCPT ); Mon, 18 May 2020 14:23:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:49722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730407AbgERRsk (ORCPT ); Mon, 18 May 2020 13:48:40 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 96D9920674; Mon, 18 May 2020 17:48:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824120; bh=depi0YMU8DCCn2TuI4u3Y9iUeIBgJt6Xy/R+eTHRwjA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hHKTgqqN2XO1+zZrT3FF36CzqZT87ZA1Q9n8TgBrgO2iAV4ypTP3pugthpVFSL+YB CJ4QNt2J/DzZWPlurUVraPvVpNemwW0jnGV51bwP8fJ1+LZ1FWgA3tDX5ROGPIFUFT PJF447TkyQkdLV4RRzPCWrMsRIjmETY/5PRKh1z8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Randall Huang , Chao Yu , Jaegeuk Kim , Ben Hutchings Subject: [PATCH 4.14 046/114] f2fs: fix to avoid accessing xattr across the boundary Date: Mon, 18 May 2020 19:36:18 +0200 Message-Id: <20200518173511.662782638@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173503.033975649@linuxfoundation.org> References: <20200518173503.033975649@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Randall Huang commit 2777e654371dd4207a3a7f4fb5fa39550053a080 upstream. 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 Signed-off-by: Randall Huang [Jaegeuk Kim: Fix wrong ending boundary] Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim [bwh: Backported to 4.14: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/xattr.c | 36 +++++++++++++++++++++++++++--------- fs/f2fs/xattr.h | 2 ++ 2 files changed, 29 insertions(+), 9 deletions(-) --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -201,12 +201,17 @@ static inline const struct xattr_handler 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, + void *last_base_addr, int index, + size_t len, const char *name) { struct f2fs_xattr_entry *entry; list_for_each_xattr(entry, base_addr) { + if ((void *)(entry) + sizeof(__u32) > last_base_addr || + (void *)XATTR_NEXT_ENTRY(entry) > last_base_addr) + return NULL; + if (entry->e_name_index != index) continue; if (entry->e_name_len != len) @@ -289,20 +294,22 @@ static int lookup_all_xattrs(struct inod const char *name, struct f2fs_xattr_entry **xe, void **base_addr, int *base_size) { - void *cur_addr, *txattr_addr, *last_addr = NULL; + void *cur_addr, *txattr_addr, *last_txattr_addr; + void *last_addr = NULL; nid_t xnid = F2FS_I(inode)->i_xattr_nid; - unsigned int size = xnid ? VALID_XATTR_BLOCK_SIZE : 0; unsigned int inline_size = inline_xattr_size(inode); int err = 0; - if (!size && !inline_size) + if (!xnid && !inline_size) return -ENODATA; - *base_size = inline_size + size + XATTR_PADDING_SIZE; + *base_size = XATTR_SIZE(xnid, inode) + XATTR_PADDING_SIZE; txattr_addr = kzalloc(*base_size, GFP_F2FS_ZERO); if (!txattr_addr) return -ENOMEM; + last_txattr_addr = (void *)txattr_addr + XATTR_SIZE(xnid, inode); + /* read from inline xattr */ if (inline_size) { err = read_inline_xattr(inode, ipage, txattr_addr); @@ -329,7 +336,11 @@ static int lookup_all_xattrs(struct inod else cur_addr = txattr_addr; - *xe = __find_xattr(cur_addr, index, len, name); + *xe = __find_xattr(cur_addr, last_txattr_addr, index, len, name); + if (!*xe) { + err = -EFAULT; + goto out; + } check: if (IS_XATTR_LAST_ENTRY(*xe)) { err = -ENODATA; @@ -562,7 +573,8 @@ static int __f2fs_setxattr(struct inode struct page *ipage, int flags) { struct f2fs_xattr_entry *here, *last; - void *base_addr; + void *base_addr, *last_base_addr; + nid_t xnid = F2FS_I(inode)->i_xattr_nid; int found, newsize; size_t len; __u32 new_hsize; @@ -586,8 +598,14 @@ static int __f2fs_setxattr(struct inode if (error) return error; + last_base_addr = (void *)base_addr + XATTR_SIZE(xnid, inode); + /* find entry with wanted name. */ - here = __find_xattr(base_addr, index, len, name); + here = __find_xattr(base_addr, last_base_addr, index, len, name); + if (!here) { + error = -EFAULT; + goto exit; + } found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1; --- a/fs/f2fs/xattr.h +++ b/fs/f2fs/xattr.h @@ -74,6 +74,8 @@ struct f2fs_xattr_entry { entry = XATTR_NEXT_ENTRY(entry)) #define VALID_XATTR_BLOCK_SIZE (PAGE_SIZE - sizeof(struct node_footer)) #define XATTR_PADDING_SIZE (sizeof(__u32)) +#define XATTR_SIZE(x,i) (((x) ? VALID_XATTR_BLOCK_SIZE : 0) + \ + (inline_xattr_size(i))) #define MIN_OFFSET(i) XATTR_ALIGN(inline_xattr_size(i) + \ VALID_XATTR_BLOCK_SIZE)