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Message-ID: <2f4a3ab4-8e9c-a8fc-ba1a-71cf6a9fbb59@linux.vnet.ibm.com>
Date: Fri, 14 Jun 2019 09:13:24 -0400
From: Nayna <nayna@...ux.vnet.ibm.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Nayna Jain <nayna@...ux.ibm.com>, linuxppc-dev@...abs.org,
linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-integrity@...r.kernel.org,
Michael Ellerman <mpe@...erman.id.au>,
Paul Mackerras <paulus@...ba.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Jeremy Kerr <jk@...abs.org>,
Matthew Garret <matthew.garret@...ula.com>,
Mimi Zohar <zohar@...ux.ibm.com>,
Claudio Carvalho <cclaudio@...ux.ibm.com>,
George Wilson <gcwilson@...ux.ibm.com>,
Elaine Palmer <erpalmer@...ibm.com>,
Eric Ricther <erichte@...ux.ibm.com>
Subject: Re: [PATCH 2/2] powerpc: expose secure variables via sysfs
On 06/14/2019 02:34 AM, Greg Kroah-Hartman wrote:
> On Thu, Jun 13, 2019 at 04:50:27PM -0400, Nayna Jain wrote:
>> As part of PowerNV secure boot support, OS verification keys are stored
>> and controlled by OPAL as secure variables. These need to be exposed to
>> the userspace so that sysadmins can perform key management tasks.
>>
>> This patch adds the support to expose secure variables via a sysfs
>> interface It reuses the the existing efi defined hooks and backend in
>> order to maintain the compatibility with the userspace tools.
>>
>> Though it reuses a great deal of efi, POWER platforms do not use EFI.
>> A new config, POWER_SECVAR_SYSFS, is defined to enable this new sysfs
>> interface.
>>
>> Signed-off-by: Nayna Jain <nayna@...ux.ibm.com>
>> ---
>> arch/powerpc/Kconfig | 2 +
>> drivers/firmware/Makefile | 1 +
>> drivers/firmware/efi/efivars.c | 2 +-
>> drivers/firmware/powerpc/Kconfig | 12 +
>> drivers/firmware/powerpc/Makefile | 3 +
>> drivers/firmware/powerpc/efi_error.c | 46 ++++
>> drivers/firmware/powerpc/secvar.c | 326 +++++++++++++++++++++++++++
>> 7 files changed, 391 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/firmware/powerpc/Kconfig
>> create mode 100644 drivers/firmware/powerpc/Makefile
>> create mode 100644 drivers/firmware/powerpc/efi_error.c
>> create mode 100644 drivers/firmware/powerpc/secvar.c
> If you add/remove/modify sysfs files, you also need to update the
> relevant Documentation/ABI/ entry as well. Please add something there
> to describe your new files when you resend the next version of this
> patch series.
>
>> diff --git a/drivers/firmware/powerpc/Kconfig b/drivers/firmware/powerpc/Kconfig
>> new file mode 100644
>> index 000000000000..e0303fc517d5
>> --- /dev/null
>> +++ b/drivers/firmware/powerpc/Kconfig
>> @@ -0,0 +1,12 @@
>> +config POWER_SECVAR_SYSFS
>> + tristate "Enable sysfs interface for POWER secure variables"
>> + default n
> default is always n, no need to list it.
>
>> --- /dev/null
>> +++ b/drivers/firmware/powerpc/efi_error.c
>> @@ -0,0 +1,46 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2019 IBM Corporation
>> + * Author: Nayna Jain <nayna@...ux.ibm.com>
>> + *
>> + * efi_error.c
>> + * - Error codes as understood by efi based tools
>> + * Taken from drivers/firmware/efi/efi.c
> Why not just export the symbol from the original file instead of
> duplicating it here?
>
>> +static int convert_buffer_to_efi_guid(u8 *buffer, efi_guid_t *guid)
>> +{
>> + u32 *a1;
>> + u16 *a2;
>> + u16 *a3;
>> +
>> + a1 = kzalloc(4, GFP_KERNEL);
> No error checking in this function for memory issues at all?
>
>> + memcpy(a1, buffer, 4);
>> + *a1 = be32_to_cpu(*a1);
>> +
>> + a2 = kzalloc(2, GFP_KERNEL);
>> + memcpy(a2, buffer+4, 2);
>> + *a2 = be16_to_cpu(*a2);
>> +
>> + a3 = kzalloc(2, GFP_KERNEL);
>> + memcpy(a3, buffer+6, 2);
>> + *a3 = be16_to_cpu(*a3);
>> +
>> + *guid = EFI_GUID(*a1, *a2, *a3, *(buffer + 8),
>> + *(buffer + 9),
>> + *(buffer + 10),
>> + *(buffer + 11),
>> + *(buffer + 12),
>> + *(buffer + 13),
>> + *(buffer + 14),
>> + *(buffer + 15));
>> +
>> + kfree(a1);
>> + kfree(a2);
>> + kfree(a3);
>> + return 0;
>> +}
>> +static efi_status_t powerpc_get_next_variable(unsigned long *name_size,
>> + efi_char16_t *name,
>> + efi_guid_t *vendor)
>> +{
>> + int rc;
>> + u8 *key;
>> + int namesize;
>> + unsigned long keylen;
>> + unsigned long keysize = 1024;
>> + unsigned long *mdsize;
>> + u8 *mdata = NULL;
>> + efi_guid_t guid;
>> +
>> + if (ucs2_strnlen(name, 1024) > 0) {
>> + createkey(name, &key, &keylen);
>> + } else {
>> + keylen = 0;
>> + key = kzalloc(1024, GFP_KERNEL);
>> + }
>> +
>> + pr_info("%s: powerpc get next variable, key is %s\n", __func__, key);
> Don't put debugging info like this in the kernel log of everyone :(
>
>> +
>> + rc = opal_get_next_variable(key, &keylen, keysize);
>> + if (rc) {
>> + kfree(key);
>> + return opal_to_efi_status(rc);
>> + }
>> +
>> + mdsize = kzalloc(sizeof(unsigned long), GFP_KERNEL);
> No error checking?
>
>> + rc = opal_get_variable_size(key, keylen, mdsize, NULL);
>> + if (rc)
>> + goto out;
>> +
>> + if (*mdsize <= 0)
>> + goto out;
>> +
>> + mdata = kzalloc(*mdsize, GFP_KERNEL);
>> +
>> + rc = opal_get_variable(key, keylen, mdata, mdsize, NULL, NULL);
>> + if (rc)
>> + goto out;
>> +
>> + if (*mdsize > 0) {
>> + namesize = *mdsize - sizeof(efi_guid_t) - sizeof(u32);
>> + if (namesize > 0) {
>> + memset(&guid, 0, sizeof(efi_guid_t));
>> + convert_buffer_to_efi_guid(mdata + namesize, &guid);
>> + memcpy(vendor, &guid, sizeof(efi_guid_t));
>> + memset(name, 0, namesize + 2);
>> + memcpy(name, mdata, namesize);
>> + *name_size = namesize + 2;
>> + name[namesize++] = 0;
>> + name[namesize] = 0;
>> + }
>> + }
>> +
>> +out:
>> + kfree(mdsize);
>> + kfree(mdata);
>> +
>> + return opal_to_efi_status(rc);
>> +}
>> +
>> +static efi_status_t powerpc_set_variable(efi_char16_t *name, efi_guid_t *vendor,
>> + u32 attr, unsigned long data_size,
>> + void *data)
>> +{
>> + int rc;
>> + u8 *key;
>> + unsigned long keylen;
>> + u8 *metadata;
>> + unsigned long mdsize;
>> +
>> + if (!name)
>> + return EFI_INVALID_PARAMETER;
>> +
>> + if (!vendor)
>> + return EFI_INVALID_PARAMETER;
>> +
>> + createkey(name, &key, &keylen);
>> + pr_info("%s: nayna key is %s\n", __func__, key);
> Again, please remove all of your debugging code when resending.
>
>> +
>> + createmetadata(name, vendor, &attr, &metadata, &mdsize);
>> +
>> + rc = opal_set_variable(key, keylen, metadata, mdsize, data, data_size);
>> +
>> + return opal_to_efi_status(rc);
>> +}
>> +
>> +
>> +static const struct efivar_operations efivar_ops = {
>> + .get_variable = powerpc_get_variable,
>> + .set_variable = powerpc_set_variable,
>> + .get_next_variable = powerpc_get_next_variable,
>> +};
>> +
>> +
>> +static __init int power_secvar_init(void)
>> +{
>> + int rc = 0;
>> + unsigned long ver = 0;
>> +
>> + rc = opal_variable_version(&ver);
>> + if (ver != BACKEND_TC_COMPAT_V1) {
>> + pr_info("Compatible backend unsupported\n");
>> + return -1;
> Do not make up error numbers, use the defined values please.
Thanks Greg for the review !!
I will address everything in the next version.
Thanks & Regards,
- Nayna
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