From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id C5DC56B000A for ; Fri, 23 Feb 2018 09:52:21 -0500 (EST) Received: by mail-wm0-f69.google.com with SMTP id 199so1460085wmi.6 for ; Fri, 23 Feb 2018 06:52:21 -0800 (PST) Received: from huawei.com (lhrrgout.huawei.com. [194.213.3.17]) by mx.google.com with ESMTPS id n130si692546wmb.33.2018.02.23.06.52.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Feb 2018 06:52:20 -0800 (PST) From: Igor Stoppa Subject: [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var Date: Fri, 23 Feb 2018 16:48:06 +0200 Message-ID: <20180223144807.1180-7-igor.stoppa@huawei.com> In-Reply-To: <20180223144807.1180-1-igor.stoppa@huawei.com> References: <20180223144807.1180-1-igor.stoppa@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: david@fromorbit.com, willy@infradead.org, keescook@chromium.org, mhocko@kernel.org Cc: labbott@redhat.com, linux-security-module@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Igor Stoppa Verify that pmalloc read-only protection is in place: trying to overwrite a protected variable will crash the kernel. Signed-off-by: Igor Stoppa --- 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; -- 2.14.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org