From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 45C646B0033 for ; Wed, 10 Jan 2018 21:03:22 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id d72so1678683pga.7 for ; Wed, 10 Jan 2018 18:03:22 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id x7sor3977060pgc.111.2018.01.10.18.03.20 for (Google Transport Security); Wed, 10 Jan 2018 18:03:20 -0800 (PST) From: Kees Cook Subject: [PATCH 04/38] lkdtm/usercopy: Adjust test to include an offset to check reporting Date: Wed, 10 Jan 2018 18:02:36 -0800 Message-Id: <1515636190-24061-5-git-send-email-keescook@chromium.org> In-Reply-To: <1515636190-24061-1-git-send-email-keescook@chromium.org> References: <1515636190-24061-1-git-send-email-keescook@chromium.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Kees Cook , Linus Torvalds , David Windsor , Alexander Viro , Andrew Morton , Andy Lutomirski , Christoph Hellwig , Christoph Lameter , "David S. Miller" , Laura Abbott , Mark Rutland , "Martin K. Petersen" , Paolo Bonzini , Christian Borntraeger , Christoffer Dall , Dave Kleikamp , Jan Kara , Luis de Bethencourt , Marc Zyngier , Rik van Riel , Matthew Garrett , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Instead of doubling the size, push the start position up by 16 bytes to still trigger an overflow. This allows to verify that offset reporting is working correctly. Signed-off-by: Kees Cook --- drivers/misc/lkdtm_usercopy.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/misc/lkdtm_usercopy.c b/drivers/misc/lkdtm_usercopy.c index a64372cc148d..9ebbb031e5e3 100644 --- a/drivers/misc/lkdtm_usercopy.c +++ b/drivers/misc/lkdtm_usercopy.c @@ -119,6 +119,8 @@ static void do_usercopy_heap_size(bool to_user) { unsigned long user_addr; unsigned char *one, *two; + void __user *test_user_addr; + void *test_kern_addr; size_t size = unconst + 1024; one = kmalloc(size, GFP_KERNEL); @@ -139,27 +141,30 @@ static void do_usercopy_heap_size(bool to_user) memset(one, 'A', size); memset(two, 'B', size); + test_user_addr = (void __user *)(user_addr + 16); + test_kern_addr = one + 16; + if (to_user) { pr_info("attempting good copy_to_user of correct size\n"); - if (copy_to_user((void __user *)user_addr, one, size)) { + if (copy_to_user(test_user_addr, test_kern_addr, size / 2)) { pr_warn("copy_to_user failed unexpectedly?!\n"); goto free_user; } pr_info("attempting bad copy_to_user of too large size\n"); - if (copy_to_user((void __user *)user_addr, one, 2 * size)) { + if (copy_to_user(test_user_addr, test_kern_addr, size)) { pr_warn("copy_to_user failed, but lacked Oops\n"); goto free_user; } } else { pr_info("attempting good copy_from_user of correct size\n"); - if (copy_from_user(one, (void __user *)user_addr, size)) { + if (copy_from_user(test_kern_addr, test_user_addr, size / 2)) { pr_warn("copy_from_user failed unexpectedly?!\n"); goto free_user; } pr_info("attempting bad copy_from_user of too large size\n"); - if (copy_from_user(one, (void __user *)user_addr, 2 * size)) { + if (copy_from_user(test_kern_addr, test_user_addr, size)) { pr_warn("copy_from_user failed, but lacked Oops\n"); goto free_user; } -- 2.7.4 -- 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