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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 81714C4360F for ; Mon, 1 Apr 2019 06:54:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C3AE2084B for ; Mon, 1 Apr 2019 06:54:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731817AbfDAGyE (ORCPT ); Mon, 1 Apr 2019 02:54:04 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:48612 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726900AbfDAGyE (ORCPT ); Mon, 1 Apr 2019 02:54:04 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id AB6802778B14DD5E2360; Mon, 1 Apr 2019 14:54:00 +0800 (CST) Received: from architecture4.huawei.com (10.140.130.215) by smtp.huawei.com (10.3.19.206) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 1 Apr 2019 14:53:52 +0800 From: Gao Xiang To: , Greg Kroah-Hartman CC: LKML , , "Chao Yu" , Chao Yu , Miao Xie , Fang Wei , Gao Xiang Subject: [PATCH for-4.19 2/2] staging: erofs: keep corrupted fs from crashing kernel in erofs_readdir() Date: Mon, 1 Apr 2019 14:53:09 +0800 Message-ID: <20190401065309.68109-2-gaoxiang25@huawei.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190401065309.68109-1-gaoxiang25@huawei.com> References: <20190401065309.68109-1-gaoxiang25@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.140.130.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 33bac912840fe64dbc15556302537dc6a17cac63 upstream. After commit 419d6efc50e9, kernel cannot be crashed in the namei path. However, corrupted nameoff can do harm in the process of readdir for scenerios without dm-verity as well. Fix it now. Fixes: 3aa8ec716e52 ("staging: erofs: add directory operations") Cc: # 4.19+ Reviewed-by: Chao Yu Signed-off-by: Gao Xiang --- drivers/staging/erofs/dir.c | 45 ++++++++++++++++++++----------------- 1 file changed, 25 insertions(+), 20 deletions(-) diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c index 04b84ff31d03..0a089cf5c78f 100644 --- a/drivers/staging/erofs/dir.c +++ b/drivers/staging/erofs/dir.c @@ -23,6 +23,21 @@ static const unsigned char erofs_filetype_table[EROFS_FT_MAX] = { [EROFS_FT_SYMLINK] = DT_LNK, }; +static void debug_one_dentry(unsigned char d_type, const char *de_name, + unsigned int de_namelen) +{ +#ifdef CONFIG_EROFS_FS_DEBUG + /* since the on-disk name could not have the trailing '\0' */ + unsigned char dbg_namebuf[EROFS_NAME_LEN + 1]; + + memcpy(dbg_namebuf, de_name, de_namelen); + dbg_namebuf[de_namelen] = '\0'; + + debugln("found dirent %s de_len %u d_type %d", dbg_namebuf, + de_namelen, d_type); +#endif +} + static int erofs_fill_dentries(struct dir_context *ctx, void *dentry_blk, unsigned *ofs, unsigned nameoff, unsigned maxsize) @@ -33,14 +48,10 @@ static int erofs_fill_dentries(struct dir_context *ctx, de = dentry_blk + *ofs; while (de < end) { const char *de_name; - int de_namelen; + unsigned int de_namelen; unsigned char d_type; -#ifdef CONFIG_EROFS_FS_DEBUG - unsigned dbg_namelen; - unsigned char dbg_namebuf[EROFS_NAME_LEN]; -#endif - if (unlikely(de->file_type < EROFS_FT_MAX)) + if (de->file_type < EROFS_FT_MAX) d_type = erofs_filetype_table[de->file_type]; else d_type = DT_UNKNOWN; @@ -48,26 +59,20 @@ static int erofs_fill_dentries(struct dir_context *ctx, nameoff = le16_to_cpu(de->nameoff); de_name = (char *)dentry_blk + nameoff; - de_namelen = unlikely(de + 1 >= end) ? - /* last directory entry */ - strnlen(de_name, maxsize - nameoff) : - le16_to_cpu(de[1].nameoff) - nameoff; + /* the last dirent in the block? */ + if (de + 1 >= end) + de_namelen = strnlen(de_name, maxsize - nameoff); + else + de_namelen = le16_to_cpu(de[1].nameoff) - nameoff; /* a corrupted entry is found */ - if (unlikely(de_namelen < 0)) { + if (unlikely(nameoff + de_namelen > maxsize || + de_namelen > EROFS_NAME_LEN)) { DBG_BUGON(1); return -EIO; } -#ifdef CONFIG_EROFS_FS_DEBUG - dbg_namelen = min(EROFS_NAME_LEN - 1, de_namelen); - memcpy(dbg_namebuf, de_name, dbg_namelen); - dbg_namebuf[dbg_namelen] = '\0'; - - debugln("%s, found de_name %s de_len %d d_type %d", __func__, - dbg_namebuf, de_namelen, d_type); -#endif - + debug_one_dentry(d_type, de_name, de_namelen); if (!dir_emit(ctx, de_name, de_namelen, le64_to_cpu(de->nid), d_type)) /* stoped by some reason */ -- 2.17.1