From patchwork Mon Jun 28 18:34:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dov Murik X-Patchwork-Id: 12348477 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 787A6C11F66 for ; Mon, 28 Jun 2021 18:34:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 52A4561C8B for ; Mon, 28 Jun 2021 18:34:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234447AbhF1ShV (ORCPT ); Mon, 28 Jun 2021 14:37:21 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54236 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234402AbhF1ShU (ORCPT ); Mon, 28 Jun 2021 14:37:20 -0400 Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 15SIXl5B040299; Mon, 28 Jun 2021 14:34:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=H6dy111e1voGFBW+BvI3b1gIFcd+YE9u4Lv0ktfnnBM=; b=FnSAvXhcovhMwwanHhhu17PIXZIKEBwFE9AEp7+7OiQnd6+daRR9eNUX8d0381fnPlLe 4zu1nd0+Wp4Vbulp02uutqAJGQNIrMp8PeyQnAU0mUwHLM4lTLVSJTxSqPYlvSRAz0e3 /DNdLd5wxzm6pfQhm+5qj27z1tyrVuyg88eDe6OgSk85qA9jZtbrsxwBzR4O/bICRNiT 1YL9TLEfRev0+DKvPMeDeeSrxFxJ/zqwPpGRlLb8CAnf7+Lzv731HnPh24k67fc70cmJ +zCbisRqcldEmRlrILDYYNOXUXVmUGj440rX4iJ5qtl262V7teXIo1oZkNkGtqhvjRiB 4w== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 39fhu2kq5t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Jun 2021 14:34:39 -0400 Received: from m0127361.ppops.net (m0127361.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 15SIYdLA044938; Mon, 28 Jun 2021 14:34:39 -0400 Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0a-001b2d01.pphosted.com with ESMTP id 39fhu2kq5p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Jun 2021 14:34:39 -0400 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 15SISAvC027398; Mon, 28 Jun 2021 18:34:38 GMT Received: from b01cxnp22033.gho.pok.ibm.com (b01cxnp22033.gho.pok.ibm.com [9.57.198.23]) by ppma02dal.us.ibm.com with ESMTP id 39duvb8msa-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Jun 2021 18:34:38 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 15SIYb4530474516 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 28 Jun 2021 18:34:37 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 44638AC060; Mon, 28 Jun 2021 18:34:37 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 06FBAAC062; Mon, 28 Jun 2021 18:34:36 +0000 (GMT) Received: from localhost.localdomain (unknown [9.2.130.16]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 28 Jun 2021 18:34:36 +0000 (GMT) From: Dov Murik To: linux-efi@vger.kernel.org Cc: Dov Murik , Laszlo Ersek , Ashish Kalra , Brijesh Singh , Tom Lendacky , Ard Biesheuvel , James Morris , "Serge E. Hallyn" , Andi Kleen , "Dr. David Alan Gilbert" , James Bottomley , Tobin Feldman-Fitzthum , Jim Cadden , linux-coco@lists.linux.dev, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 0/3] Allow access to confidential computing secret area Date: Mon, 28 Jun 2021 18:34:28 +0000 Message-Id: <20210628183431.953934-1-dovmurik@linux.ibm.com> X-Mailer: git-send-email 2.25.1 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: PFCNBpUcIe_-Ouc9gJIW3AkqEQE85WnA X-Proofpoint-GUID: OWE6BPlPz7Vdes6vOC-8u9azeZ5imWyl X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-06-28_14:2021-06-25,2021-06-28 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 malwarescore=0 mlxscore=0 adultscore=0 suspectscore=0 mlxlogscore=999 spamscore=0 phishscore=0 priorityscore=1501 clxscore=1011 impostorscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2106280121 Precedence: bulk List-ID: Confidential computing hardware such as AMD SEV (Secure Encrypted Virtualization) allows guest owners to inject secrets into the VMs memory without the host/hypervisor being able to read them. In SEV, secret injection is performed early in the VM launch process, before the guest starts running. Support for secret injection is already available in OVMF (in its AmdSev package; see edk2 commit 01726b6d23d4 "OvmfPkg/AmdSev: Expose the Sev Secret area using a configuration table" [1]), but the secrets were not available in the guest kernel. The patch series copies the secrets from the EFI-provided memory to kernel reserved memory, and optionally exposes them to userspace via securityfs using a new sev_secret kernel module. The first patch in efi/libstub copies the secret area from the EFI memory to specially allocated memory; the second patch reserves that memory block; and the third patch introduces the new sev_secret module that exposes the content of the secret entries as securityfs files, and allows clearing out secrets with a file unlink interface. This has been tested with AMD SEV guests, but the kernel side of handling the secret area has no SEV-specific dependencies, and therefore should be usable for any confidential computing hardware that can publish the secret area via the standard EFI config table entry. Here is a simple example for usage of the sev_secret module in a guest to which secrets were injected during launch: # modprobe sev_secret # ls -la /sys/kernel/security/sev_secret/ total 0 drwxr-xr-x 2 root root 0 Jun 28 11:54 . drwxr-xr-x 3 root root 0 Jun 28 11:54 .. -r--r----- 1 root root 0 Jun 28 11:54 736870e5-84f0-4973-92ec-06879ce3da0b -r--r----- 1 root root 0 Jun 28 11:54 83c83f7f-1356-4975-8b7e-d3a0b54312c6 -r--r----- 1 root root 0 Jun 28 11:54 9553f55d-3da2-43ee-ab5d-ff17f78864d2 -r--r----- 1 root root 0 Jun 28 11:54 e6f5a162-d67f-4750-a67c-5d065f2a9910 # xxd /sys/kernel/security/sev_secret/e6f5a162-d67f-4750-a67c-5d065f2a9910 00000000: 7468 6573 652d 6172 652d 7468 652d 6b61 these-are-the-ka 00000010: 7461 2d73 6563 7265 7473 0001 0203 0405 ta-secrets...... 00000020: 0607 .. # rm /sys/kernel/security/sev_secret/e6f5a162-d67f-4750-a67c-5d065f2a9910 # ls -la /sys/kernel/security/sev_secret/ total 0 drwxr-xr-x 2 root root 0 Jun 28 11:55 . drwxr-xr-x 3 root root 0 Jun 28 11:54 .. -r--r----- 1 root root 0 Jun 28 11:54 736870e5-84f0-4973-92ec-06879ce3da0b -r--r----- 1 root root 0 Jun 28 11:54 83c83f7f-1356-4975-8b7e-d3a0b54312c6 -r--r----- 1 root root 0 Jun 28 11:54 9553f55d-3da2-43ee-ab5d-ff17f78864d2 [1] https://github.com/tianocore/edk2/commit/01726b6d23d4 v2 changes: - Add unlink support in sev_secret securityfs. Dov Murik (3): efi/libstub: Copy confidential computing secret area efi: Reserve confidential computing secret area virt: Add sev_secret module to expose confidential computing secrets drivers/firmware/efi/Makefile | 2 +- drivers/firmware/efi/confidential-computing.c | 41 +++ drivers/firmware/efi/efi.c | 5 + drivers/firmware/efi/libstub/Makefile | 3 +- .../efi/libstub/confidential-computing.c | 68 ++++ drivers/firmware/efi/libstub/efi-stub.c | 2 + drivers/firmware/efi/libstub/efistub.h | 2 + drivers/firmware/efi/libstub/x86-stub.c | 2 + drivers/virt/Kconfig | 2 + drivers/virt/Makefile | 1 + drivers/virt/sev_secret/Kconfig | 11 + drivers/virt/sev_secret/Makefile | 2 + drivers/virt/sev_secret/sev_secret.c | 298 ++++++++++++++++++ include/linux/efi.h | 11 + 14 files changed, 448 insertions(+), 2 deletions(-) create mode 100644 drivers/firmware/efi/confidential-computing.c create mode 100644 drivers/firmware/efi/libstub/confidential-computing.c create mode 100644 drivers/virt/sev_secret/Kconfig create mode 100644 drivers/virt/sev_secret/Makefile create mode 100644 drivers/virt/sev_secret/sev_secret.c base-commit: 62fb9874f5da54fdb243003b386128037319b219