From: Dov Murik <dovmurik@linux.ibm.com>
To: Borislav Petkov <bp@suse.de>
Cc: linux-efi@vger.kernel.org, Laszlo Ersek <lersek@redhat.com>,
Ashish Kalra <ashish.kalra@amd.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Ard Biesheuvel <ardb@kernel.org>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
Andi Kleen <ak@linux.intel.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
James Bottomley <jejb@linux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@linux.ibm.com>,
Jim Cadden <jcadden@ibm.com>,
linux-coco@lists.linux.dev,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, Dov Murik <dovmurik@linux.ibm.com>
Subject: Re: [RFC PATCH v2 3/3] virt: Add sev_secret module to expose confidential computing secrets
Date: Tue, 29 Jun 2021 10:23:49 +0300 [thread overview]
Message-ID: <6e35f6db-9c5b-3c75-a66b-de1392295f6a@linux.ibm.com> (raw)
In-Reply-To: <YNojYBIwk0xCHQ0v@zn.tnic>
On 28/06/2021 22:30, Borislav Petkov wrote:
> On Mon, Jun 28, 2021 at 06:34:31PM +0000, Dov Murik wrote:
>> The new sev_secret module exposes the confidential computing secret area
>> via securityfs interface.
>>
>> When the module is loaded (and securityfs is mounted, typically under
>> /sys/kernel/security), an "sev_secret" directory is created in
>> securityfs. In it, a file is created for each secret entry. The name
>> of each such file is the GUID of the secret entry, and its content is
>> the secret data.
>>
>> This allows applications running in a confidential computing setting to
>> read secrets provided by the guest owner via a secure secret injection
>> mechanism (such as AMD SEV's LAUNCH_SECRET command).
>>
>> Removing (unlinking) files in the "sev_secret" directory will zero out
>> the secret in memory, and remove the filesystem entry. If the module
>> is removed and loaded again, that secret will not appear in the
>> filesystem.
>>
>> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
>> ---
>> 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 +++++++++++++++++++++++++++
>> 5 files changed, 314 insertions(+)
>> 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
>
> Same question here: maybe have
>
> drivers/virt/coco/
>
> and put all coco guest stuff in there.
>
I agree, according to what comes up of the conversation we have in
replies to the cover letter.
>> diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig
>> index 8061e8ef449f..c222cc625891 100644
>> --- a/drivers/virt/Kconfig
>> +++ b/drivers/virt/Kconfig
>> @@ -36,4 +36,6 @@ source "drivers/virt/vboxguest/Kconfig"
>> source "drivers/virt/nitro_enclaves/Kconfig"
>>
>> source "drivers/virt/acrn/Kconfig"
>> +
>> +source "drivers/virt/sev_secret/Kconfig"
>> endif
>> diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile
>> index 3e272ea60cd9..0765e5418d1d 100644
>> --- a/drivers/virt/Makefile
>> +++ b/drivers/virt/Makefile
>> @@ -8,3 +8,4 @@ obj-y += vboxguest/
>>
>> obj-$(CONFIG_NITRO_ENCLAVES) += nitro_enclaves/
>> obj-$(CONFIG_ACRN_HSM) += acrn/
>> +obj-y += sev_secret/
>> diff --git a/drivers/virt/sev_secret/Kconfig b/drivers/virt/sev_secret/Kconfig
>> new file mode 100644
>> index 000000000000..4505526b8ef1
>> --- /dev/null
>> +++ b/drivers/virt/sev_secret/Kconfig
>> @@ -0,0 +1,11 @@
>> +# SPDX-License-Identifier: GPL-2.0-only
>> +config AMD_SEV_SECRET_SECURITYFS
>> + tristate "AMD SEV secret area securityfs support"
>> + depends on EFI
>
> That probably needs to depend on CONFIG_AMD_MEM_ENCRYPT - otherwise
> what's the point for it.
>
But not if it's a generic driver that is useful for other confidential
computing implementations. Consider some non-encrypting guest memory
isolation mechanism where the host can't read most guest pages; this
module might be useful there too.
Also, isn't it a bit weird to depend on CONFIG_AMD_MEM_ENCRYPT but not
use any of its APIs?
-Dov
next prev parent reply other threads:[~2021-06-29 7:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-28 18:34 [RFC PATCH v2 0/3] Allow access to confidential computing secret area Dov Murik
2021-06-28 18:34 ` [RFC PATCH v2 1/3] efi/libstub: Copy " Dov Murik
2021-06-28 18:34 ` [RFC PATCH v2 2/3] efi: Reserve " Dov Murik
2021-06-28 20:40 ` Tom Lendacky
2021-06-29 6:04 ` Dov Murik
2021-06-28 18:34 ` [RFC PATCH v2 3/3] virt: Add sev_secret module to expose confidential computing secrets Dov Murik
2021-06-28 19:30 ` Borislav Petkov
2021-06-29 7:23 ` Dov Murik [this message]
2021-06-29 22:48 ` Borislav Petkov
2021-06-28 19:28 ` [RFC PATCH v2 0/3] Allow access to confidential computing secret area Borislav Petkov
2021-06-29 7:16 ` Dov Murik
2021-06-29 17:33 ` Borislav Petkov
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