From patchwork Mon Jul 17 18:17:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haitao Huang X-Patchwork-Id: 13316248 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 2D1A5C001DE for ; Mon, 17 Jul 2023 18:18:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230288AbjGQSSU (ORCPT ); Mon, 17 Jul 2023 14:18:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231892AbjGQSSJ (ORCPT ); Mon, 17 Jul 2023 14:18:09 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7F8110F8; Mon, 17 Jul 2023 11:17:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689617867; x=1721153867; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=KMhbm2LT8v9HkqUZrNtgnMM3fiXJ5sNz/f0BPaAE4K4=; b=ZKxHQbalMSyRiDs79SnJcPpnC0vSIWCmDpqLZdOcKi4Ox/MpOYoVW17P Q7mgrV06YAk0i7k5/HA4RmMpDWPmqW3X3yeR92TdnAQkQIYQ6afQ1Vpv9 qEY0shXmitslfZ+Kr6Lv+7/zqk8HTC2tBWTGE9Urtni82Us4yVxqRbK+J 0LxN8IuXxsWPSmmKuF0FSPG+XKTQWuCbwb60GuHd8h2ZjPj0We5Twx64u 8Diwfh1IIn0Wmz31K2T7B8019uaEmdF0mMkPJhqqmBI3PDVHtJyx5XJZn rxJiheT9+ramqpesTbdhU0hjJhjB9I0tJHbQzV0DU0gdKwXN2ov6vtgzP g==; X-IronPort-AV: E=McAfee;i="6600,9927,10774"; a="396833365" X-IronPort-AV: E=Sophos;i="6.01,211,1684825200"; d="scan'208";a="396833365" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jul 2023 11:17:33 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10774"; a="726647808" X-IronPort-AV: E=Sophos;i="6.01,211,1684825200"; d="scan'208";a="726647808" Received: from b4969161e530.jf.intel.com ([10.165.56.46]) by fmsmga007.fm.intel.com with ESMTP; 17 Jul 2023 11:17:32 -0700 From: Haitao Huang To: jarkko@kernel.org, dave.hansen@linux.intel.com, linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" Cc: kai.huang@intel.com, reinette.chatre@intel.com, kristen@linux.intel.com, seanjc@google.com, stable@vger.kernel.org Subject: [PATCH] x86/sgx: fix a NULL pointer Date: Mon, 17 Jul 2023 11:17:32 -0700 Message-Id: <20230717181732.84039-1-haitao.huang@linux.intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Under heavy load, the SGX EPC reclaimers (current ksgxd or future EPC cgroup worker) may reclaim the SECS EPC page for an enclave and set encl->secs.epc_page to NULL. But the SECS EPC page is used for EAUG in the SGX #PF handler without checking for NULL and reloading. Fix this by checking if SECS is loaded before EAUG and load it if it was reclaimed. Fixes: 5a90d2c3f5ef8 ("x86/sgx: Support adding of pages to an initialized enclave") Cc: stable@vger.kernel.org Signed-off-by: Haitao Huang --- arch/x86/kernel/cpu/sgx/encl.c | 25 ++++++++++++++++++++----- arch/x86/kernel/cpu/sgx/main.c | 4 ++++ 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 2a0e90fe2abc..d39e502bb7b0 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -235,6 +235,16 @@ static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page, return epc_page; } +static struct sgx_epc_page *sgx_encl_load_secs(struct sgx_encl *encl) +{ + struct sgx_epc_page *epc_page = encl->secs.epc_page; + + if (!epc_page) { + epc_page = sgx_encl_eldu(&encl->secs, NULL); + } + return epc_page; +} + static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, struct sgx_encl_page *entry) { @@ -248,11 +258,9 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, return entry; } - if (!(encl->secs.epc_page)) { - epc_page = sgx_encl_eldu(&encl->secs, NULL); - if (IS_ERR(epc_page)) - return ERR_CAST(epc_page); - } + epc_page = sgx_encl_load_secs(encl); + if (IS_ERR(epc_page)) + return ERR_CAST(epc_page); epc_page = sgx_encl_eldu(entry, encl->secs.epc_page); if (IS_ERR(epc_page)) @@ -339,6 +347,13 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma, mutex_lock(&encl->lock); + epc_page = sgx_encl_load_secs(encl); + if (IS_ERR(epc_page)) { + if (PTR_ERR(epc_page) == -EBUSY) + vmret = VM_FAULT_NOPAGE; + goto err_out_unlock; + } + epc_page = sgx_alloc_epc_page(encl_page, false); if (IS_ERR(epc_page)) { if (PTR_ERR(epc_page) == -EBUSY) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 166692f2d501..4662a364ce62 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -257,6 +257,10 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, mutex_lock(&encl->lock); + /* Should not be possible */ + if (WARN_ON(!(encl->secs.epc_page))) + goto out; + sgx_encl_ewb(epc_page, backing); encl_page->epc_page = NULL; encl->secs_child_cnt--;