From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754119AbbHEPuF (ORCPT ); Wed, 5 Aug 2015 11:50:05 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:56767 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753863AbbHEPt3 (ORCPT ); Wed, 5 Aug 2015 11:49:29 -0400 From: James Hogan To: CC: , , James Hogan , Kees Cook , Andrew Morton Subject: [PATCH 6/7] test_user_copy: Check user string accessors Date: Wed, 5 Aug 2015 16:48:54 +0100 Message-ID: <1438789735-4643-7-git-send-email-james.hogan@imgtec.com> X-Mailer: git-send-email 2.3.6 In-Reply-To: <1438789735-4643-1-git-send-email-james.hogan@imgtec.com> References: <1438789735-4643-1-git-send-email-james.hogan@imgtec.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [192.168.154.110] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add basic success/failure checking of the user string functions which copy or find the length of userland strings. The following cases are checked: - strncpy_from_user() with legitimate user to kernel addresses, illegal all-kernel and reversed addresses, and legitimate all-kernel addresses. - strnlen_user()/strlen_user() with a legitimate user address, an illegal kernel address, and a legitimate kernel address. This caught a bug in the MIPS Enhanced Virtual Memory (EVA) implementation: test_user_copy: illegal strlen_user passed Due to strlen_user() accidentally always using normal kernel loads, and the EVA user/kernel address ranges overlapping. New tests: - legitimate strncpy_from_user - legitimate strnlen_user - legitimate strlen_user - illegal all-kernel strncpy_from_user - illegal reversed strncpy_from_user - illegal strnlen_user - illegal strlen_user - legitimate all-kernel strncpy_from_user - legitimate kernel strnlen_user - legitimate kernel strlen_user Signed-off-by: James Hogan Cc: Kees Cook Cc: Andrew Morton --- lib/test_user_copy.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c index 6cbdb0a15ca2..6d05ec5f6cfa 100644 --- a/lib/test_user_copy.c +++ b/lib/test_user_copy.c @@ -72,6 +72,12 @@ static int __init test_user_copy_init(void) "legitimate put_user failed"); ret |= test(clear_user(usermem, PAGE_SIZE) != 0, "legitimate clear_user passed"); + ret |= test(strncpy_from_user(kmem, usermem, PAGE_SIZE) < 0, + "legitimate strncpy_from_user failed"); + ret |= test(strnlen_user(usermem, PAGE_SIZE) == 0, + "legitimate strnlen_user failed"); + ret |= test(strlen_user(usermem) == 0, + "legitimate strlen_user failed"); ret |= test(!access_ok(VERIFY_READ, usermem, PAGE_SIZE * 2), "legitimate access_ok VERIFY_READ failed"); @@ -122,6 +128,16 @@ static int __init test_user_copy_init(void) "illegal put_user passed"); ret |= test(clear_user((char __user *)kmem, PAGE_SIZE) != PAGE_SIZE, "illegal kernel clear_user passed"); + ret |= test(strncpy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE), + PAGE_SIZE) >= 0, + "illegal all-kernel strncpy_from_user passed"); + ret |= test(strncpy_from_user(bad_usermem, (char __user *)kmem, + PAGE_SIZE) >= 0, + "illegal reversed strncpy_from_user passed"); + ret |= test(strnlen_user((char __user *)kmem, PAGE_SIZE) != 0, + "illegal strnlen_user passed"); + ret |= test(strlen_user((char __user *)kmem) != 0, + "illegal strlen_user passed"); /* * If unchecked user accesses (__*) on this architecture cannot access @@ -201,6 +217,13 @@ static int __init test_user_copy_init(void) "legitimate kernel put_user failed"); ret |= test(clear_user((char __user *)kmem, PAGE_SIZE) != 0, "legitimate kernel clear_user failed"); + ret |= test(strncpy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE), + PAGE_SIZE) < 0, + "legitimate all-kernel strncpy_from_user failed"); + ret |= test(strnlen_user((char __user *)kmem, PAGE_SIZE) == 0, + "legitimate kernel strnlen_user failed"); + ret |= test(strlen_user((char __user *)kmem) == 0, + "legitimate kernel strlen_user failed"); ret |= test(!access_ok(VERIFY_READ, (char __user *)kmem, PAGE_SIZE * 2), "legitimate kernel access_ok VERIFY_READ failed"); -- 2.3.6