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 */
get_cert_list(u8 * key,unsigned long keylen,uint64_t * size)21 static __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 */
load_powerpc_certs(void)51 static 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 }
96 late_initcall(load_powerpc_certs);
97