From patchwork Tue Feb 1 22:47:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 12732399 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C74B5C433EF for ; Tue, 1 Feb 2022 22:47:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232447AbiBAWrP (ORCPT ); Tue, 1 Feb 2022 17:47:15 -0500 Received: from mga09.intel.com ([134.134.136.24]:18697 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239234AbiBAWrO (ORCPT ); Tue, 1 Feb 2022 17:47:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643755634; x=1675291634; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kkaZuACiZ0ejAq9qCfv3ISOiQAYfbcK3eJHzVdB5CKk=; b=F8nNAN+NBuHPp+cxFDGoXaItUxccqIQMu9kXLLlWuGh5FFz01OW5Iv19 +lTnsXAZwhkoHJE2/tzcywVJnm3/Z4D9roVXikdfCUUMBebZHfnRMlEH0 85MG/+bS3VEI4311CribFtYA4sUl1XkdHKb4987bJOVaS7kMtGHJlN5jy SPNCdF1QkkBcnk+w91x/YDvmjGevYRgFvtEZZk9J+yQNrP+AJnJJHNxVM mSHGElrNXeLOOJYn6hri9leStgJoNjCxdEssHb37bvJ1ZDjFrHiFabLMV lE8nzwMIbyxoMSzSX4fbEO5U7mloBRWn10LcBJ3LyIu1vEhoZlu3coKai g==; X-IronPort-AV: E=McAfee;i="6200,9189,10245"; a="247582280" X-IronPort-AV: E=Sophos;i="5.88,335,1635231600"; d="scan'208";a="247582280" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 14:47:14 -0800 X-IronPort-AV: E=Sophos;i="5.88,335,1635231600"; d="scan'208";a="698584742" Received: from rchatre-ws.ostc.intel.com ([10.54.69.144]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 14:47:14 -0800 From: Reinette Chatre To: jarkko@kernel.org, dave.hansen@linux.intel.com, linux-sgx@vger.kernel.org, shuah@kernel.org Cc: linux-kselftest@vger.kernel.org Subject: [PATCH V2 1/4] selftests/sgx: Fix NULL-pointer-dereference upon early test failure Date: Tue, 1 Feb 2022 14:47:03 -0800 Message-Id: <89824888783fd8e770bfc64530c7549650a41851.1643754040.git.reinette.chatre@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org == Background == The SGX selftests track parts of the enclave binaries in an array: encl->segment_tbl[]. That array is dynamically allocated early (but not first) in the test's lifetime. The array is referenced at the end of the test in encl_delete(). == Problem == encl->segment_tbl[] can be NULL if the test fails before its allocation. That leads to a NULL-pointer-dereference in encl_delete(). This is triggered during early failures of the selftest like if the enclave binary ("test_encl.elf") is deleted. == Solution == Ensure encl->segment_tbl[] is valid before attempting to access its members. The offset with which it is accessed, encl->nr_segments, is initialized before encl->segment_tbl[] and thus considered valid to use after the encl->segment_tbl[] check succeeds. Fixes: 3200505d4de6 ("selftests/sgx: Create a heap for the test enclave") Signed-off-by: Reinette Chatre Acked-by: Shuah Khan Reviewed-by: Jarkko Sakkinen --- Changes since V1: - Rewrite commit message (Dave). tools/testing/selftests/sgx/load.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/sgx/load.c b/tools/testing/selftests/sgx/load.c index 9d4322c946e2..006b464c8fc9 100644 --- a/tools/testing/selftests/sgx/load.c +++ b/tools/testing/selftests/sgx/load.c @@ -21,7 +21,7 @@ void encl_delete(struct encl *encl) { - struct encl_segment *heap_seg = &encl->segment_tbl[encl->nr_segments - 1]; + struct encl_segment *heap_seg; if (encl->encl_base) munmap((void *)encl->encl_base, encl->encl_size); @@ -32,10 +32,11 @@ void encl_delete(struct encl *encl) if (encl->fd) close(encl->fd); - munmap(heap_seg->src, heap_seg->size); - - if (encl->segment_tbl) + if (encl->segment_tbl) { + heap_seg = &encl->segment_tbl[encl->nr_segments - 1]; + munmap(heap_seg->src, heap_seg->size); free(encl->segment_tbl); + } memset(encl, 0, sizeof(*encl)); }