From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C48C7B for ; Tue, 12 Apr 2022 10:03:19 +0000 (UTC) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 23C9ofqG028851; Tue, 12 Apr 2022 10:02:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding : mime-version; s=pp1; bh=Vt6n7rhSvbiZiXE+7BsBnFt8Ntc1LCCyPzh6g1rRUxU=; b=fzzD7dGzoC1QrrLl+YNfeetKpTDGR80M/D8C3o20+94OxB3nu514S8ogTVoLKl/dVJ1V m20TthRSB6GNp638dWVD2KDlIB8QwQcA3mhhooPaRj6m+mSF2Yt8l7CXG68EPgCTmjkt StP98VoKt2DN1CY2+7XRp+gkGBtbZLStomJ/ylpnstolywEwrzubKg8DH0lKyWlnGYn6 ga75RQ6CJ2DTuPl57ObnLbaSWCsvJDvBovDi/aL+s9PcoY1DItpPqnGxt11FeoLUgYFI QplKyaJQ10o/OAXP4QrnbHeKORBX/iNbKI6GsKijf+apDerDWAoacOG9tgQwRkw7hqvJ wQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 3fd75b87ju-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Apr 2022 10:02:58 +0000 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 23C9sHXe009475; Tue, 12 Apr 2022 10:02:57 GMT Received: from ppma04wdc.us.ibm.com (1a.90.2fa9.ip4.static.sl-reverse.com [169.47.144.26]) by mx0b-001b2d01.pphosted.com with ESMTP id 3fd75b87jd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Apr 2022 10:02:57 +0000 Received: from pps.filterd (ppma04wdc.us.ibm.com [127.0.0.1]) by ppma04wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 23C9vOcE005053; Tue, 12 Apr 2022 10:02:56 GMT Received: from b01cxnp23032.gho.pok.ibm.com (b01cxnp23032.gho.pok.ibm.com [9.57.198.27]) by ppma04wdc.us.ibm.com with ESMTP id 3fb1s9pxa3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Apr 2022 10:02:56 +0000 Received: from b01ledav006.gho.pok.ibm.com (b01ledav006.gho.pok.ibm.com [9.57.199.111]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 23CA2u7H26542516 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Apr 2022 10:02:56 GMT Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 36FB0AC062; Tue, 12 Apr 2022 10:02:56 +0000 (GMT) Received: from b01ledav006.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6C67DAC05F; Tue, 12 Apr 2022 10:02:51 +0000 (GMT) Received: from [9.160.177.197] (unknown [9.160.177.197]) by b01ledav006.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 12 Apr 2022 10:02:51 +0000 (GMT) Message-ID: <48e087af-cc93-72f0-3907-9d1978530b87@linux.ibm.com> Date: Tue, 12 Apr 2022 13:02:50 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v9 0/4] Allow guest access to EFI confidential computing secret area Content-Language: en-US To: linux-efi@vger.kernel.org, Ard Biesheuvel Cc: Borislav Petkov , Ashish Kalra , Brijesh Singh , Tom Lendacky , James Morris , "Serge E. Hallyn" , Andi Kleen , Greg KH , Andrew Scull , Dave Hansen , "Dr. David Alan Gilbert" , Gerd Hoffmann , Lenny Szubowicz , Peter Gonda , Matthew Garrett , James Bottomley , Tobin Feldman-Fitzthum , Jim Cadden , Daniele Buono , linux-coco@lists.linux.dev, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Dov Murik References: <20220331215607.3182232-1-dovmurik@linux.ibm.com> From: Dov Murik In-Reply-To: <20220331215607.3182232-1-dovmurik@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: T3qRxDNlN6r8eqtw7ub0MrpOnmxtEw7I X-Proofpoint-ORIG-GUID: pJteWlSp4i2XDpI8NyF3htK0jyuJvNud Content-Transfer-Encoding: 7bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-04-12_03,2022-04-11_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 adultscore=0 bulkscore=0 impostorscore=0 clxscore=1015 mlxscore=0 mlxlogscore=999 spamscore=0 priorityscore=1501 lowpriorityscore=0 malwarescore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2204120048 On 01/04/2022 0:56, Dov Murik wrote: > Confidential computing (coco) 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. > > OVMF already reserves designated area for secret injection (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 keeps the address of the EFI-provided memory for > injected secrets, and exposes the secrets to userspace via securityfs > using a new efi_secret kernel module. The module is autoloaded (by the > EFI driver) if the secret area is populated. > > The first patch in EFI keeps the address of the secret area as passed in > the EFI configuration table. The second patch introduces the new > efi_secret module that exposes the content of the secret entries as > securityfs files, and allows clearing out secrets with a file unlink > interface. The third patch auto-loads the efi_secret module during > startup if the injected secrets area is populated. The last patch > documents the data flow of confidential computing secret injection. > > As a usage example, consider a guest performing computations on > encrypted files. The Guest Owner provides the decryption key (= secret) > using the secret injection mechanism. The guest application reads the > secret from the efi_secret filesystem and proceeds to decrypt the files > into memory and then performs the needed computations on the content. > > In this example, the host can't read the files from the disk image > because they are encrypted. Host can't read the decryption key because > it is passed using the secret injection mechanism (= secure channel). > Host can't read the decrypted content from memory because it's a > confidential (memory-encrypted) guest. > > This has been tested with AMD SEV and SEV-ES guests, but the kernel side > of handling the secret area has no SEV-specific dependencies, and > therefore might be usable (perhaps with minor changes) for any > confidential computing hardware that can publish the secret area via the > standard EFI config table entry. > > To enable this functionality, set CONFIG_EFI_SECRET=m when building the > guest kernel. > > Here is a simple example for usage of the efi_secret module in a guest > to which an EFI secret area with 4 secrets was injected during launch: > > ... > [ 0.000000] efi: EFI v2.70 by EDK II > [ 0.000000] efi: CocoSecret=0x7f222680 SMBIOS=0x7f541000 ACPI=0x7f77e000 ACPI 2.0=0x7f77e014 MEMATTR=0x7ea16418 > ... > [ 1.127627] Run /init as init process > Loading, please wait... > Starting version 245.4-4ubuntu3.15 > ... > [ 0.763204] efi_secret efi_secret.0: Created 4 entries in securityfs secrets/coco > ... > > # ls -la /sys/kernel/security/secrets/coco > 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 > > # hd /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910 > 00000000 74 68 65 73 65 2d 61 72 65 2d 74 68 65 2d 6b 61 |these-are-the-ka| > 00000010 74 61 2d 73 65 63 72 65 74 73 00 01 02 03 04 05 |ta-secrets......| > 00000020 06 07 |..| > 00000022 > > # rm /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910 > > # ls -la /sys/kernel/security/secrets/coco > 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 > > > --- > > v9 changes: > - Change the module into a platform driver (thanks Ard) > - Remove special auto-loading code in efi; instead register a platform > device (udev will load the efi_secret module) (thanks Ard) > - Change logging in the efi_secret module to dev_err() etc. > - efi_secret: first check that the secret area header is valid; only then start > creating securityfs dirs. > > v8: https://lore.kernel.org/linux-coco/20220228114254.1099945-1-dovmurik@linux.ibm.com/ > v8 changes: > - Change path of filesystem to /secrets/coco and fix the > documentation accordingly (Thanks Gerd, Matthew) > - Remove patch 2/5 (of v7) because the latest OVMF release (edk2-stable202202) > already contains the fix to mark the launch secret page as EFI_RESERVED_TYPE. > > v7: https://lore.kernel.org/linux-coco/20220201124413.1093099-1-dovmurik@linux.ibm.com/ > v7 changes: > - Improve description of efi_secret module in Kconfig. > - Fix sparse warnings on pointer address space mismatch > (Reported-by: kernel test robot ) > > v6: https://lore.kernel.org/linux-coco/20211129114251.3741721-1-dovmurik@linux.ibm.com/ > v6 changes: > - Autoload the efi_secret module if the secret area is populated > (thanks Greg KH). > - efi_secret: Depend on X86_64 because we use ioremap_encrypted() which > is only defined for this arch. > - efi_secret.c: Remove unneeded tableheader_guid local variable. > - Documentation fixes. > > v5: https://lore.kernel.org/linux-coco/20211118113359.642571-1-dovmurik@linux.ibm.com/ > v5 changes: > - Simplify EFI code: instead of copying the secret area, the firmware > marks the secret area as EFI_RESERVED_TYPE, and then the uefi_init() > code just keeps the pointer as it appears in the EFI configuration > table. The use of reserved pages is similar to the AMD SEV-SNP > patches for handling SNP-Secrets and SNP-CPUID pages. > - In order to handle OVMF releases out there which mark the > confidential computing secrets page as EFI_BOOT_SERVICES_DATA, add > efi/libstub code that detects this and fixes the E820 map to reserve > this page. > - In the efi_secret module code, map the secrets page using > ioremap_encrypted (again, similar to the AMD SEV-SNP guest patches > for accessing SNP-Secrets and SNP-CPUID pages). > - Add documentation in Documentation/security/coco/efi_secret. > > v4: https://lore.kernel.org/linux-coco/20211020061408.3447533-1-dovmurik@linux.ibm.com/ > v4 changes: > - Guard all the new EFI and efi-stub code (patches 1+2) with #ifdef > CONFIG_EFI_COCO_SECRET (thanks Greg KH). Selecting > CONFIG_EFI_SECRET=m (patch 3) will enable the EFI parts as well. > - Guard call to clflush_cache_range() with #ifdef CONFIG_X86 > (Reported-by: kernel test robot ) > > v3: https://lore.kernel.org/linux-coco/20211014130848.592611-1-dovmurik@linux.ibm.com/ > v3 changes: > - Rename the module to efi_secret > - Remove the exporting of clean_cache_range > - Use clflush_cache_range in wipe_memory > - Document function wipe_memory > - Initialize efi.coco_secret to EFI_INVALID_TABLE_ADDR to correctly detect > when there's no secret area published in the EFI configuration tables > > v2: https://lore.kernel.org/linux-coco/20211007061838.1381129-1-dovmurik@linux.ibm.com > v2 changes: > - Export clean_cache_range() > - When deleteing a secret, call clean_cache_range() after explicit_memzero > - Add Documentation/ABI/testing/securityfs-coco-sev_secret > > v1: https://lore.kernel.org/linux-coco/20210809190157.279332-1-dovmurik@linux.ibm.com/ > > RFC: https://lore.kernel.org/linux-coco/20210628183431.953934-1-dovmurik@linux.ibm.com/ > > > > Dov Murik (4): > efi: Save location of EFI confidential computing area > virt: Add efi_secret module to expose confidential computing secrets > efi: Register efi_secret platform device if EFI secret area is > declared > docs: security: Add secrets/coco documentation > This series has Reviewed-by tags on all patches (though, as I mentioned, there's a missing #ifdef in patch 3). Ard, are you going to take this through the EFI tree? Should I resend the series with the fix for patch 3? Thanks, -Dov > Documentation/ABI/testing/securityfs-secrets-coco | 51 +++ > Documentation/security/index.rst | 1 + > Documentation/security/secrets/coco.rst | 103 ++++++ > Documentation/security/secrets/index.rst | 9 + > arch/x86/platform/efi/efi.c | 3 + > drivers/firmware/efi/Kconfig | 16 + > drivers/firmware/efi/efi.c | 9 + > drivers/virt/Kconfig | 3 + > drivers/virt/Makefile | 1 + > drivers/virt/coco/efi_secret/Kconfig | 16 + > drivers/virt/coco/efi_secret/Makefile | 2 + > drivers/virt/coco/efi_secret/efi_secret.c | 349 ++++++++++++++++++++ > include/linux/efi.h | 10 + > 13 files changed, 573 insertions(+) > create mode 100644 Documentation/ABI/testing/securityfs-secrets-coco > create mode 100644 Documentation/security/secrets/coco.rst > create mode 100644 Documentation/security/secrets/index.rst > create mode 100644 drivers/virt/coco/efi_secret/Kconfig > create mode 100644 drivers/virt/coco/efi_secret/Makefile > create mode 100644 drivers/virt/coco/efi_secret/efi_secret.c > > > base-commit: 7e57714cd0ad2d5bb90e50b5096a0e671dec1ef3