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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2019 IBM Corporation
* Author: Nayna Jain
*
* - loads keys and hashes stored and controlled by the firmware.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <asm/secure_boot.h>
#include <asm/secvar.h>
#include "keyring_handler.h"
#include "../integrity.h"
#define extract_esl(db, data, size, offset) \
do { db = data + offset; size = size - offset; } while (0)
/*
* Get a certificate list blob from the named secure variable.
*
* Returns:
* - a pointer to a kmalloc'd buffer containing the cert list on success
* - NULL if the key does not exist
* - an ERR_PTR on error
*/
static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
{
int rc;
void *db;
rc = secvar_ops->get(key, keylen, NULL, size);
if (rc) {
if (rc == -ENOENT)
return NULL;
return ERR_PTR(rc);
}
db = kmalloc(*size, GFP_KERNEL);
if (!db)
return ERR_PTR(-ENOMEM);
rc = secvar_ops->get(key, keylen, db, size);
if (rc) {
kfree(db);
return ERR_PTR(rc);
}
return db;
}
/*
* Load the certs contained in the keys databases into the platform trusted
* keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist
* keyring.
*/
static int __init load_powerpc_certs(void)
{
void *db = NULL, *dbx = NULL, *data = NULL;
u64 dsize = 0;
u64 offset = 0;
int rc = 0;
ssize_t len;
char buf[32];
if (!secvar_ops)
return -ENODEV;
len = secvar_ops->format(buf, sizeof(buf));
if (len <= 0)
return -ENODEV;
// Check for known secure boot implementations from OPAL or PLPKS
if (strcmp("ibm,edk2-compat-v1", buf) && strcmp("ibm,plpks-sb-v1", buf)) {
pr_err("Unsupported secvar implementation \"%s\", not loading certs\n", buf);
return -ENODEV;
}
if (strcmp("ibm,plpks-sb-v1", buf) == 0)
/* PLPKS authenticated variables ESL data is prefixed with 8 bytes of timestamp */
offset = 8;
/*
* Get db, and dbx. They might not exist, so it isn't an error if we
* can't get them.
*/
data = get_cert_list("db", 3, &dsize);
if (!data) {
pr_info("Couldn't get db list from firmware\n");
} else if (IS_ERR(data)) {
rc = PTR_ERR(data);
pr_err("Error reading db from firmware: %d\n", rc);
return rc;
} else {
extract_esl(db, data, dsize, offset);
rc = parse_efi_signature_list("powerpc:db", db, dsize,
get_handler_for_db);
if (rc)
pr_err("Couldn't parse db signatures: %d\n", rc);
kfree(data);
}
data = get_cert_list("dbx", 4, &dsize);
if (!data) {
pr_info("Couldn't get dbx list from firmware\n");
} else if (IS_ERR(data)) {
rc = PTR_ERR(data);
pr_err("Error reading dbx from firmware: %d\n", rc);
return rc;
} else {
extract_esl(dbx, data, dsize, offset);
rc = parse_efi_signature_list("powerpc:dbx", dbx, dsize,
get_handler_for_dbx);
if (rc)
pr_err("Couldn't parse dbx signatures: %d\n", rc);
kfree(data);
}
return rc;
}
late_initcall(load_powerpc_certs);
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