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Message-ID: <20190614063443.GB17056@kroah.com>
Date: Fri, 14 Jun 2019 08:34:43 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Nayna Jain <nayna@...ux.ibm.com>
Cc: 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 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 k-h
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