From patchwork Wed Feb 28 20:06:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Igor Stoppa X-Patchwork-Id: 10249581 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 3F91660211 for ; Wed, 28 Feb 2018 20:11:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C12328B0C for ; Wed, 28 Feb 2018 20:11:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 20BC228DF3; Wed, 28 Feb 2018 20:11:32 +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 8B7A828B0C for ; Wed, 28 Feb 2018 20:11:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934068AbeB1ULa (ORCPT ); Wed, 28 Feb 2018 15:11:30 -0500 Received: from lhrrgout.huawei.com ([194.213.3.17]:27899 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934011AbeB1UL3 (ORCPT ); Wed, 28 Feb 2018 15:11:29 -0500 Received: from LHREML712-CAH.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id C9484E9A5449F; Wed, 28 Feb 2018 20:11:26 +0000 (GMT) Received: from localhost.localdomain (10.122.225.51) by smtpsuk.huawei.com (10.201.108.35) with Microsoft SMTP Server (TLS) id 14.3.361.1; Wed, 28 Feb 2018 20:11:22 +0000 From: Igor Stoppa To: , , , CC: , , , , , Igor Stoppa Subject: [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var Date: Wed, 28 Feb 2018 22:06:19 +0200 Message-ID: <20180228200620.30026-7-igor.stoppa@huawei.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20180228200620.30026-1-igor.stoppa@huawei.com> References: <20180228200620.30026-1-igor.stoppa@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.122.225.51] X-CFilter-Loop: Reflected Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Verify that pmalloc read-only protection is in place: trying to overwrite a protected variable will crash the kernel. Signed-off-by: Igor Stoppa Reviewed-by: Jay Freyensee --- drivers/misc/lkdtm.h | 1 + drivers/misc/lkdtm_core.c | 3 +++ drivers/misc/lkdtm_perms.c | 28 ++++++++++++++++++++++++++++ 3 files changed, 32 insertions(+) diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h index 9e513dcfd809..dcda3ae76ceb 100644 --- a/drivers/misc/lkdtm.h +++ b/drivers/misc/lkdtm.h @@ -38,6 +38,7 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void); void __init lkdtm_perms_init(void); void lkdtm_WRITE_RO(void); void lkdtm_WRITE_RO_AFTER_INIT(void); +void lkdtm_WRITE_RO_PMALLOC(void); void lkdtm_WRITE_KERN(void); void lkdtm_EXEC_DATA(void); void lkdtm_EXEC_STACK(void); diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c index 2154d1bfd18b..c9fd42bda6ee 100644 --- a/drivers/misc/lkdtm_core.c +++ b/drivers/misc/lkdtm_core.c @@ -155,6 +155,9 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(ACCESS_USERSPACE), CRASHTYPE(WRITE_RO), CRASHTYPE(WRITE_RO_AFTER_INIT), +#ifdef CONFIG_PROTECTABLE_MEMORY + CRASHTYPE(WRITE_RO_PMALLOC), +#endif CRASHTYPE(WRITE_KERN), CRASHTYPE(REFCOUNT_INC_OVERFLOW), CRASHTYPE(REFCOUNT_ADD_OVERFLOW), diff --git a/drivers/misc/lkdtm_perms.c b/drivers/misc/lkdtm_perms.c index 53b85c9d16b8..0ac9023fd2b0 100644 --- a/drivers/misc/lkdtm_perms.c +++ b/drivers/misc/lkdtm_perms.c @@ -9,6 +9,7 @@ #include #include #include +#include #include /* Whether or not to fill the target memory area with do_nothing(). */ @@ -104,6 +105,33 @@ void lkdtm_WRITE_RO_AFTER_INIT(void) *ptr ^= 0xabcd1234; } +#ifdef CONFIG_PROTECTABLE_MEMORY +void lkdtm_WRITE_RO_PMALLOC(void) +{ + struct gen_pool *pool; + int *i; + + pool = pmalloc_create_pool("pool", 0); + if (unlikely(!pool)) { + pr_info("Failed preparing pool for pmalloc test."); + return; + } + + i = (int *)pmalloc(pool, sizeof(int), GFP_KERNEL); + if (unlikely(!i)) { + pr_info("Failed allocating memory for pmalloc test."); + pmalloc_destroy_pool(pool); + return; + } + + *i = INT_MAX; + pmalloc_protect_pool(pool); + + pr_info("attempting bad pmalloc write at %p\n", i); + *i = 0; +} +#endif + void lkdtm_WRITE_KERN(void) { size_t size;