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 D7B81C10F11 for ; Wed, 10 Apr 2019 09:27:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CF062133D for ; Wed, 10 Apr 2019 09:27:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="KewiMEBQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729879AbfDJJ1i (ORCPT ); Wed, 10 Apr 2019 05:27:38 -0400 Received: from mail-yb1-f201.google.com ([209.85.219.201]:39711 "EHLO mail-yb1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727964AbfDJJ1h (ORCPT ); Wed, 10 Apr 2019 05:27:37 -0400 Received: by mail-yb1-f201.google.com with SMTP id u125so1296076ybf.6 for ; Wed, 10 Apr 2019 02:27:36 -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=IqFv1AQJLSe0cAEqxckv6f9Un/Y2FytgRM8jbJdiFxM=; b=KewiMEBQSX61LVb7I4tp711G8sYPbtpUD50rarh2a74g3F76fa6Dbkusvsz4bLyhVA q1ZPe9hqA+PFqc3j5pkxNu+Q7bdGG5HKOOKGWSabO6xtU1U+JKZDlUSZ2w3//l8KY8KJ OLsV9yCnBwrQMk4hDFL9bfzis4ezJPA9ZuTei93t9j/Als0Ln1c5bMrUPNW5on8TDgpc 7EE9Iov2+XrU9Vuyc5CjhlPBDGlU4UcdcLt+e7C6QndDdToHLA3XfHQ4/K4b+f63aVjT mMLPjOhfOTJw/XLSAbAmZBriX84zBBmm/d23DREjnfIKOsw2IjguTzOfmOou+2N5CMIQ Gwhw== 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=IqFv1AQJLSe0cAEqxckv6f9Un/Y2FytgRM8jbJdiFxM=; b=gYIcoVHKE0i9iOxWvEnu6GPoA8H+8iXAlj1tvsDCWw9rM6REuNtbVc9xarETZNmaq8 /1xgd5JyecHMCaUaSAXszOTqoN5o41QHTA7u/1Q4A9F6QEaUZiB8tcKfRdRt4aEeeVo5 BtKZRCZ+DYsv4qCPH3VR3cKDmiHkaAO1np7WpHtoBYx7a5SaqLwFQ5KtHVO4oKsQgZRX 9WSNbdttF+0wpi2IZSnZzGh9q4jMQrvJFJk0czfujA1eyQk5KFZuY9j2A7VYPqwCyL9Q +SuyncgNdA3wbZsnCc5CssyUi0TpuLHJ3Q3iyLJw+GkAh1xagCaPxa8Y9SR1KeI4GWMj oeqw== X-Gm-Message-State: APjAAAXRFALF/Eg0aIHVin0ovqVgsseJFr5mXv22C38pYmzhM4oPKXeb sbtcXL3Mwgt4hspLPV5ovsbl3CBv7zccjbZmQig= X-Google-Smtp-Source: APXvYqzVvGiIYrMtb9PgdSAjZ8CisL0CYTNnE1PxVSm/4e5HC7brN3Wh893+8t6EKJc64QQ71G6aQ2ZxjOYrstUI/No= X-Received: by 2002:a25:40c4:: with SMTP id n187mr6216423yba.16.1554888456456; Wed, 10 Apr 2019 02:27:36 -0700 (PDT) Date: Wed, 10 Apr 2019 17:27:30 +0800 Message-Id: <20190410092730.72358-1-huangrandall@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH v4] 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 v3: * fix typo in setxattr() v4: * change boundry definition --- fs/f2fs/xattr.c | 34 +++++++++++++++++++++++++++++----- 1 file changed, 29 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c index 848a785abe25..a1cf53c727b2 100644 --- a/fs/f2fs/xattr.c +++ b/fs/f2fs/xattr.c @@ -202,12 +202,18 @@ 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, + 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) + + sizeof(__u32) > last_base_addr) + return NULL; + if (entry->e_name_index != index) continue; if (entry->e_name_len != len) @@ -298,6 +304,7 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage, void **base_addr, int *base_size) { void *cur_addr, *txattr_addr, *last_addr = NULL; + void *last_txattr_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); @@ -311,6 +318,9 @@ static int lookup_all_xattrs(struct inode *inode, struct page *ipage, if (!txattr_addr) return -ENOMEM; + last_txattr_addr = (void *)txattr_addr + inline_size + size + + XATTR_PADDING_SIZE - 1; + /* read from inline xattr */ if (inline_size) { err = read_inline_xattr(inode, ipage, txattr_addr); @@ -337,7 +347,11 @@ 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, last_txattr_addr, index, len, name); + if (!*xe) { + err = -EFAULT; + goto out; + } check: if (IS_XATTR_LAST_ENTRY(*xe)) { err = -ENODATA; @@ -581,10 +595,15 @@ static int __f2fs_setxattr(struct inode *inode, int index, struct page *ipage, int flags) { struct f2fs_xattr_entry *here, *last; - void *base_addr; + void *base_addr, *last_base_addr = NULL; 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 + xattr_nid_size + + XATTR_PADDING_SIZE; int error = 0; if (name == NULL) @@ -604,9 +623,14 @@ static int __f2fs_setxattr(struct inode *inode, int index, error = read_all_xattrs(inode, ipage, &base_addr); if (error) return error; + last_base_addr = (void *)base_addr + max_size - 1; /* 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; -- 2.21.0.392.gf8f6787159e-goog