From patchwork Tue Jun 6 09:57:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Su Yue X-Patchwork-Id: 9768425 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 238B060352 for ; Tue, 6 Jun 2017 09:55:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 069DA2679B for ; Tue, 6 Jun 2017 09:55:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EF3FC26E56; Tue, 6 Jun 2017 09:55:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8BB082679B for ; Tue, 6 Jun 2017 09:55:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751580AbdFFJzr (ORCPT ); Tue, 6 Jun 2017 05:55:47 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:31983 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751455AbdFFJzT (ORCPT ); Tue, 6 Jun 2017 05:55:19 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="19712901" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 06 Jun 2017 17:55:05 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (unknown [10.167.33.83]) by cn.fujitsu.com (Postfix) with ESMTP id 8663847CA8C0; Tue, 6 Jun 2017 17:55:04 +0800 (CST) Received: from localhost.localdomain (10.167.226.129) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 6 Jun 2017 17:55:03 +0800 From: Su Yue To: CC: Subject: [PATCH v3 1/9] btrfs: Introduce btrfs_is_name_len_valid to avoid reading beyond boundary Date: Tue, 6 Jun 2017 17:57:00 +0800 Message-ID: <20170606095708.494-2-suy.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170606095708.494-1-suy.fnst@cn.fujitsu.com> References: <20170606095708.494-1-suy.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.129] X-yoursite-MailScanner-ID: 8663847CA8C0.AA314 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: suy.fnst@cn.fujitsu.com Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Introduce function btrfs_is_name_len_valid. The function compares arg @name_len with item boundary then returns value represents name_len is valid or not. Signed-off-by: Su Yue --- fs/btrfs/ctree.h | 2 ++ fs/btrfs/dir-item.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 75 insertions(+) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 643c70d2b2e6..776b16ec7a47 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3037,6 +3037,8 @@ struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info, struct btrfs_path *path, const char *name, int name_len); +bool btrfs_is_name_len_valid(struct extent_buffer *leaf, int slot, + unsigned long start, u16 name_len); /* orphan.c */ int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c index c24d615e3d7f..b54c920c8412 100644 --- a/fs/btrfs/dir-item.c +++ b/fs/btrfs/dir-item.c @@ -484,3 +484,76 @@ int verify_dir_item(struct btrfs_fs_info *fs_info, return 0; } + +bool btrfs_is_name_len_valid(struct extent_buffer *leaf, int slot, + unsigned long start, u16 name_len) +{ + struct btrfs_fs_info *fs_info = leaf->fs_info; + struct btrfs_key key; + u32 read_start; + u32 read_end; + u32 item_start; + u32 item_end; + u32 size; + bool ret = true; + + ASSERT(start > btrfs_leaf_data(leaf)); + + read_start = start - btrfs_leaf_data(leaf); + read_end = read_start + name_len; + item_start = btrfs_item_offset_nr(leaf, slot); + item_end = btrfs_item_end_nr(leaf, slot); + + btrfs_item_key_to_cpu(leaf, &key, slot); + + switch (key.type) { + case BTRFS_DIR_ITEM_KEY: + case BTRFS_XATTR_ITEM_KEY: + case BTRFS_DIR_INDEX_KEY: + size = sizeof(struct btrfs_dir_item); + break; + case BTRFS_INODE_REF_KEY: + size = sizeof(struct btrfs_inode_ref); + break; + case BTRFS_INODE_EXTREF_KEY: + size = sizeof(struct btrfs_inode_extref); + break; + case BTRFS_ROOT_REF_KEY: + case BTRFS_ROOT_BACKREF_KEY: + size = sizeof(struct btrfs_root_ref); + break; + default: + ret = false; + goto out; + } + + if (read_start < item_start) { + ret = false; + goto out; + } + if (read_end > item_end) { + ret = false; + goto out; + } + + /* there shall be item(s) before name */ + if (read_start - item_start < size) { + ret = false; + goto out; + } + + /* + * This may be the last item in the slot + * Or same type item(s) is left between read_end and item_end + */ + if (item_end != read_end && + item_end - read_end < size) { + ret = false; + goto out; + } +out: + if (!ret) + btrfs_crit(fs_info, "invalid dir item name len: %u", + (unsigned int)name_len); + return ret; +}