tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 <asm/secure_boot.h>
14#include <asm/secvar.h>
15#include "keyring_handler.h"
16#include "../integrity.h"
17
18/*
19 * Get a certificate list blob from the named secure variable.
20 *
21 * Returns:
22 * - a pointer to a kmalloc'd buffer containing the cert list on success
23 * - NULL if the key does not exist
24 * - an ERR_PTR on error
25 */
26static __init void *get_cert_list(u8 *key, unsigned long keylen, u64 *size)
27{
28 int rc;
29 void *db;
30
31 rc = secvar_ops->get(key, keylen, NULL, size);
32 if (rc) {
33 if (rc == -ENOENT)
34 return NULL;
35 return ERR_PTR(rc);
36 }
37
38 db = kmalloc(*size, GFP_KERNEL);
39 if (!db)
40 return ERR_PTR(-ENOMEM);
41
42 rc = secvar_ops->get(key, keylen, db, size);
43 if (rc) {
44 kfree(db);
45 return ERR_PTR(rc);
46 }
47
48 return db;
49}
50
51/*
52 * Load the certs contained in the keys databases into the platform trusted
53 * keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist
54 * keyring.
55 */
56static int __init load_powerpc_certs(void)
57{
58 void *db = NULL, *dbx = NULL;
59 u64 dbsize = 0, dbxsize = 0;
60 int rc = 0;
61 ssize_t len;
62 char buf[32];
63
64 if (!secvar_ops)
65 return -ENODEV;
66
67 len = secvar_ops->format(buf, sizeof(buf));
68 if (len <= 0)
69 return -ENODEV;
70
71 // Check for known secure boot implementations from OPAL or PLPKS
72 if (strcmp("ibm,edk2-compat-v1", buf) && strcmp("ibm,plpks-sb-v1", buf)) {
73 pr_err("Unsupported secvar implementation \"%s\", not loading certs\n", buf);
74 return -ENODEV;
75 }
76
77 /*
78 * Get db, and dbx. They might not exist, so it isn't an error if we
79 * can't get them.
80 */
81 db = get_cert_list("db", 3, &dbsize);
82 if (!db) {
83 pr_info("Couldn't get db list from firmware\n");
84 } else if (IS_ERR(db)) {
85 rc = PTR_ERR(db);
86 pr_err("Error reading db from firmware: %d\n", rc);
87 return rc;
88 } else {
89 rc = parse_efi_signature_list("powerpc:db", db, dbsize,
90 get_handler_for_db);
91 if (rc)
92 pr_err("Couldn't parse db signatures: %d\n", rc);
93 kfree(db);
94 }
95
96 dbx = get_cert_list("dbx", 4, &dbxsize);
97 if (!dbx) {
98 pr_info("Couldn't get dbx list from firmware\n");
99 } else if (IS_ERR(dbx)) {
100 rc = PTR_ERR(dbx);
101 pr_err("Error reading dbx from firmware: %d\n", rc);
102 return rc;
103 } else {
104 rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize,
105 get_handler_for_dbx);
106 if (rc)
107 pr_err("Couldn't parse dbx signatures: %d\n", rc);
108 kfree(dbx);
109 }
110
111 return rc;
112}
113late_initcall(load_powerpc_certs);