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);