cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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load_powerpc.c (2174B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (C) 2019 IBM Corporation
      4 * Author: Nayna Jain
      5 *
      6 *      - loads keys and hashes stored and controlled by the firmware.
      7 */
      8#include <linux/kernel.h>
      9#include <linux/sched.h>
     10#include <linux/cred.h>
     11#include <linux/err.h>
     12#include <linux/slab.h>
     13#include <linux/of.h>
     14#include <asm/secure_boot.h>
     15#include <asm/secvar.h>
     16#include "keyring_handler.h"
     17
     18/*
     19 * Get a certificate list blob from the named secure variable.
     20 */
     21static __init void *get_cert_list(u8 *key, unsigned long keylen, uint64_t *size)
     22{
     23	int rc;
     24	void *db;
     25
     26	rc = secvar_ops->get(key, keylen, NULL, size);
     27	if (rc) {
     28		pr_err("Couldn't get size: %d\n", rc);
     29		return NULL;
     30	}
     31
     32	db = kmalloc(*size, GFP_KERNEL);
     33	if (!db)
     34		return NULL;
     35
     36	rc = secvar_ops->get(key, keylen, db, size);
     37	if (rc) {
     38		kfree(db);
     39		pr_err("Error reading %s var: %d\n", key, rc);
     40		return NULL;
     41	}
     42
     43	return db;
     44}
     45
     46/*
     47 * Load the certs contained in the keys databases into the platform trusted
     48 * keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist
     49 * keyring.
     50 */
     51static int __init load_powerpc_certs(void)
     52{
     53	void *db = NULL, *dbx = NULL;
     54	uint64_t dbsize = 0, dbxsize = 0;
     55	int rc = 0;
     56	struct device_node *node;
     57
     58	if (!secvar_ops)
     59		return -ENODEV;
     60
     61	/* The following only applies for the edk2-compat backend. */
     62	node = of_find_compatible_node(NULL, NULL, "ibm,edk2-compat-v1");
     63	if (!node)
     64		return -ENODEV;
     65
     66	/*
     67	 * Get db, and dbx. They might not exist, so it isn't an error if we
     68	 * can't get them.
     69	 */
     70	db = get_cert_list("db", 3, &dbsize);
     71	if (!db) {
     72		pr_err("Couldn't get db list from firmware\n");
     73	} else {
     74		rc = parse_efi_signature_list("powerpc:db", db, dbsize,
     75					      get_handler_for_db);
     76		if (rc)
     77			pr_err("Couldn't parse db signatures: %d\n", rc);
     78		kfree(db);
     79	}
     80
     81	dbx = get_cert_list("dbx", 4,  &dbxsize);
     82	if (!dbx) {
     83		pr_info("Couldn't get dbx list from firmware\n");
     84	} else {
     85		rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize,
     86					      get_handler_for_dbx);
     87		if (rc)
     88			pr_err("Couldn't parse dbx signatures: %d\n", rc);
     89		kfree(dbx);
     90	}
     91
     92	of_node_put(node);
     93
     94	return rc;
     95}
     96late_initcall(load_powerpc_certs);