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// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
/* Copyright 2013-2019 IBM Corp. */
#ifndef pr_fmt
#define pr_fmt(fmt) "STB: " fmt
#endif
#include <skiboot.h>
#include <device.h>
#include <nvram.h>
#include <opal-api.h>
#include <inttypes.h>
#include "secureboot.h"
static const void* hw_key_hash = NULL;
static size_t hw_key_hash_size;
static bool secure_mode = false;
static bool secure_init = false;
static unsigned int level = PR_ERR;
static struct {
enum secureboot_version version;
const char *compat;
} secureboot_map[] = {
{ IBM_SECUREBOOT_V1, "ibm,secureboot-v1" },
{ IBM_SECUREBOOT_SOFTROM, "ibm,secureboot-v1-softrom" },
{ IBM_SECUREBOOT_V2, "ibm,secureboot-v2" },
};
void secureboot_enforce(void)
{
/* Sanity check */
if (!secure_mode)
return;
/*
* TODO: Ideally, the BMC should decide what security policy to apply
* (power off, reboot, switch PNOR sides, etc). We may need to provide
* extra info to BMC other than just abort. Terminate Immediate
* Attention ? (TI)
*/
prlog(PR_EMERG, "secure mode enforced, aborting.\n");
abort();
}
bool secureboot_is_compatible(struct dt_node *node, int *version, const char **compat)
{
int i;
if (!node)
return false;
for (i = 0; i < ARRAY_SIZE(secureboot_map); i++) {
if (dt_node_is_compatible(node, secureboot_map[i].compat)) {
if (version)
*version = secureboot_map[i].version;
if (compat)
*compat = secureboot_map[i].compat;
return true;
}
}
return false;
}
bool is_fw_secureboot(void)
{
return secure_mode;
}
void secureboot_init(void)
{
struct dt_node *node;
const char *hash_algo;
const char *compat = NULL;
int version;
size_t size;
node = dt_find_by_path(dt_root, "/ibm,secureboot");
if (!node) {
prlog(PR_NOTICE, "secure boot not supported\n");
return;
}
if (!secureboot_is_compatible(node, &version, &compat)) {
/**
* @fwts-label SecureBootNotCompatible
* @fwts-advice Compatible secureboot driver not found. Probably,
* hostboot/mambo/skiboot has updated the
* /ibm,secureboot/compatible without adding a driver that
* supports it.
*/
prlog(PR_ERR, "%s FAILED, /ibm,secureboot not compatible.\n",
__func__);
return;
}
prlog(PR_DEBUG, "Found %s\n", compat);
if (nvram_query_eq_dangerous("force-secure-mode", "always")) {
secure_mode = true;
prlog(PR_NOTICE, "secure mode on (FORCED by nvram)\n");
} else {
secure_mode = dt_has_node_property(node, "secure-enabled", NULL);
prlog(PR_INFO, "secure mode %s\n",
secure_mode ? "on" : "off");
}
/* Use emergency log level only when secure mode is ON */
if (secure_mode)
level = PR_EMERG;
else
level = PR_ERR;
if (version == IBM_SECUREBOOT_V1 ||
version == IBM_SECUREBOOT_SOFTROM) {
hash_algo = dt_prop_get(node, "hash-algo");
if (strcmp(hash_algo, "sha512")) {
/**
* @fwts-label HashAlgoInvalid
* @fwts-advice Hash algorithm invalid, secureboot
* containers version 1 requires sha512. If you're
* running the latest POWER firmware, so probably there
* is a bug in the device tree received from hostboot.
*/
prlog(level, "secureboot init FAILED, hash-algo=%s "
"not supported\n", hash_algo);
secureboot_enforce();
}
hw_key_hash_size = SHA512_DIGEST_LENGTH;
} else if (version == IBM_SECUREBOOT_V2) {
hw_key_hash_size = dt_prop_get_u32(node, "hw-key-hash-size");
if (hw_key_hash_size == 0) {
prlog(level, "hw-key-hash-size=%zd too short\n",
hw_key_hash_size);
secureboot_enforce();
}
if (hw_key_hash_size > SHA512_DIGEST_LENGTH) {
prlog(level, "hw-key-hash-size=%zd too big\n",
hw_key_hash_size);
secureboot_enforce();
}
} else {
prlog(level, "%s FAILED. /ibm,secureboot not supported",
__func__);
secureboot_enforce();
}
hw_key_hash = dt_prop_get_def_size(node, "hw-key-hash", NULL, &size);
if (!hw_key_hash) {
prlog(level, "hw-key-hash not found\n");
secureboot_enforce();
}
if (size != hw_key_hash_size) {
prlog(level, "hw_key-hash wrong size %zd (expected=%zd)\n",
size, hw_key_hash_size);
secureboot_enforce();
}
if (cvc_init())
secureboot_enforce();
secure_init = true;
}
int secureboot_verify(enum resource_id id, void *buf, size_t len)
{
const char *name;
__be64 log;
int rc = -1;
name = flash_map_resource_name(id);
if (!name) {
prlog(level, "container NOT VERIFIED, resource_id=%d "
"unknown\n", id);
secureboot_enforce();
return -1;
}
if (!secure_init) {
prlog(level, "container NOT VERIFIED, resource_id=%d "
"secureboot not yet initialized\n", id);
secureboot_enforce();
return -1;
}
rc = call_cvc_verify(buf, len, hw_key_hash, hw_key_hash_size, &log);
if (rc == OPAL_SUCCESS) {
prlog(PR_NOTICE, "%s verified\n", name);
} else if (rc == OPAL_PARTIAL) {
/*
* The value returned in log indicates what checking has
* failed. Return codes defined in
* /hostboot/src/include/securerom/status_codes.H
*/
prlog(level, "%s verification FAILED. log=0x%" PRIx64 "\n",
name, be64_to_cpu(log));
secureboot_enforce();
} else if (rc == OPAL_PARAMETER) {
prlog(level, "%s NOT VERIFIED, invalid param. buf=%p, "
"len=%zd key-hash=%p hash-size=%zd\n", name, buf, len,
hw_key_hash, hw_key_hash_size);
secureboot_enforce();
} else if (rc == OPAL_UNSUPPORTED) {
prlog(level, "%s NOT VERIFIED, CVC-verify service not "
"supported\n", name);
secureboot_enforce();
} else {
prlog(level, "%s NOT VERIFIED, unknown CVC-verify error. "
"rc=%d\n", name, rc);
secureboot_enforce();
}
return 0;
}
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