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 6505DC10F0E for ; Tue, 9 Apr 2019 08:37:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2BDA420833 for ; Tue, 9 Apr 2019 08:37:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="oDcJB2Iq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726744AbfDIIhe (ORCPT ); Tue, 9 Apr 2019 04:37:34 -0400 Received: from mail-vs1-f73.google.com ([209.85.217.73]:46996 "EHLO mail-vs1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726001AbfDIIhe (ORCPT ); Tue, 9 Apr 2019 04:37:34 -0400 Received: by mail-vs1-f73.google.com with SMTP id y138so2755632vsc.13 for ; Tue, 09 Apr 2019 01:37:33 -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=NWmuyWOAWbPWH9U7dkYKdVIZC9kxT49Hao9GlBVtRBc=; b=oDcJB2IqL/+fPwiFZ+xAodTkhbD2dmBmhj5Xep3GtfzDa4bqYzA1af1ORYF0/rWK+5 U7Phh1ATwKqFqNfzsLkawpPi1uv3UN245thXNlf9WP+E1Q9p9eY0CJ+4VaOAY8RUVd6i Kh4dEMTS4YLBdVIlpUTHM9NvE3eDVMcSS/rQnO1M9ARI29nGWxTcZ//Bvxwrxh4xSnyC zB6ImhcAP6ArcvWEI/XrjPvPO8LZBMNvgBGONnCiVTmuSBNi2z+iRlU7e9xSUpN7j1Sb r7vsmMsoYg5Ah5+eVQdqR3R9bLbIB5L1rZtV2fWABLKUImYQoygEjcmhyp66dFgXr1N/ GEZw== 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=NWmuyWOAWbPWH9U7dkYKdVIZC9kxT49Hao9GlBVtRBc=; b=udSOTy7PkDLV5RCFd8xjzoO/sVBmoqS+X8FN1VrD6X5Iq2RA6k7ZZAYXps3Y+bxWhG ruJunsUbgreBvFGey3TMR9dpjsmB6kpS+gp9cGsIxP7KcjKxV9ejqoBfMlGL4j+lvnHQ V5+8nfJJjqk/J5WFnuCLt8jDx1/9jX+Woe/Av6KTo0pB4gUtUGxS29Azr6W6cVVMCCRm bF9rtQr67PqCVwEo0PYBVJYSDM1YeDM9oMsEbDt7iRH8nVKrShK9d7bh39P3Ux5fmaoE iJCJAYwe3maIcahnq66IDtd/uFKumH7CcALZKdw7nGnYVnwf8XdyDhk6mVbSJ+I1nYh2 j2SQ== X-Gm-Message-State: APjAAAVe0YtFvchV4UdWTM8HnEwCOvwqy64Ke62Z2+wyxhs/DeuJIWlP /aeAksZ1ejQTtGP+DJdtlzWZFeeNH+71KYR39+Y= X-Google-Smtp-Source: APXvYqylRBsOslmn3JqBY1Ko0adAz3bfW0Odb1pMqn00feLWMmfVuBVXZE1916j16QWpfw1fLCX8S6xhhjrj8xhqDcY= X-Received: by 2002:ab0:6039:: with SMTP id n25mr866623ual.25.1554799052890; Tue, 09 Apr 2019 01:37:32 -0700 (PDT) Date: Tue, 9 Apr 2019 16:37:26 +0800 Message-Id: <20190409083726.181522-1-huangrandall@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH v2] 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 --- v2: * return EFAULT if OOB error is detected --- fs/f2fs/xattr.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 848a785abe25..f60e40d95bbf 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, + unsigned int max_size, int index, + size_t len, const char *name) { struct f2fs_xattr_entry *entry; + void *max_addr = base_addr + ENTRY_SIZE(XATTR_ENTRY(base_addr)) + + max_size - 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) @@ -301,6 +306,7 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage, 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); + unsigned int max_size = inline_size + size + XATTR_PADDING_SIZE; int err = 0; if (!size && !inline_size) @@ -323,6 +329,7 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage, *base_size = inline_size; goto check; } + max_size -= inline_size; } /* read from xattr node block */ @@ -330,6 +337,8 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage, err = read_xattr_block(inode, txattr_addr); if (err) goto out; + + max_size -= size; } if (last_addr) @@ -337,7 +346,12 @@ 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, max_size, index, len, name); + if (!*xe) { + err = -EFAULT; + goto out; + } + check: if (IS_XATTR_LAST_ENTRY(*xe)) { err = -ENODATA; @@ -585,6 +599,10 @@ static int __f2fs_setxattr(struct inode *inode, int index, int found, newsize; size_t len; __u32 new_hsize; + nid_t xnid = F2FS_I(inode)->i_xattr_nid; + unsigned int xattr_nid_size = xnid ? VALID_XATTR_BLOCK_SIZE : 0; + unsigned int inline_size = inline_xattr_size(inode); + unsigned int max_size = inline_size + size + XATTR_PADDING_SIZE; int error = 0; if (name == NULL) @@ -606,7 +624,11 @@ 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, max_size, index, len, name); + if (!here) { + error = -EFAULT; + goto exit; + } found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1; -- 2.21.0.392.gf8f6787159e-goog