From patchwork Mon Jul 17 20:29:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haitao Huang X-Patchwork-Id: 13316574 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 B4958EB64DC for ; Mon, 17 Jul 2023 20:29:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229582AbjGQU3l (ORCPT ); Mon, 17 Jul 2023 16:29:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229496AbjGQU3k (ORCPT ); Mon, 17 Jul 2023 16:29:40 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEE2C188; Mon, 17 Jul 2023 13:29:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689625779; x=1721161779; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=X8jjGorvvakFNZSiXbU5g+XQSAuUt8rUfwsivIw+/D4=; b=ItJ1Dy1niyG7hjHIbgFk/+ao9cg+xuuEfllINT6qFABopX/zytE+9GWC 2rgxulZUYU2JW8IH7G8lZSoRJh4/27sQFZg2JZ3IclvAMWe5vhi8eJItg nX4jtR7ewYjPGQi8Eq1a/kxNK2kzpKUj+bxY3hz/G+dfnuZuOrSm789xS +GzcMhLX/DHES3ZrkMetuq59AaFJKNkR+Rw31QIv6KOmGmhIRSBpXARAU maHjF+Y3HK0njKD4Tq0HIpukeCc5GW/ijfD2Mpqx7YsvMk1SpJw9W7qP+ bsAU83pWsMUOvdQ2dM9EtZsXYsMoackEJ/1U/pa4aUVw9o8kn7JMgQCgb g==; X-IronPort-AV: E=McAfee;i="6600,9927,10774"; a="345625644" X-IronPort-AV: E=Sophos;i="6.01,211,1684825200"; d="scan'208";a="345625644" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Jul 2023 13:29:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="866838387" Received: from b4969161e530.jf.intel.com ([10.165.56.46]) by fmsmga001.fm.intel.com with ESMTP; 17 Jul 2023 13:29:39 -0700 From: Haitao Huang To: "Jarkko Sakkinen" , "Haitao Huang" , 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 13:29:38 -0700 Message-Id: <20230717202938.94989-1-haitao.huang@linux.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 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 Reviewed-by: Jarkko Sakkinen --- 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..2ab544da1664 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--;