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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Intel Corporation
*
* Author:
* Dmitry Kasatkin <dmitry.kasatkin@intel.com>
*/
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/kernel_read_file.h>
#include <linux/key-type.h>
#include <linux/digsig.h>
#include <linux/vmalloc.h>
#include <crypto/public_key.h>
#include <keys/system_keyring.h>
#include "integrity.h"
static struct key *keyring[INTEGRITY_KEYRING_MAX];
static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
#ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
"_evm",
"_ima",
#else
".evm",
".ima",
#endif
".platform",
".machine",
};
#ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
#define restrict_link_to_ima restrict_link_by_digsig_builtin_and_secondary
#else
#define restrict_link_to_ima restrict_link_by_digsig_builtin
#endif
static struct key *integrity_keyring_from_id(const unsigned int id)
{
if (id >= INTEGRITY_KEYRING_MAX)
return ERR_PTR(-EINVAL);
if (!keyring[id]) {
keyring[id] =
request_key(&key_type_keyring, keyring_name[id], NULL);
if (IS_ERR(keyring[id])) {
int err = PTR_ERR(keyring[id]);
pr_err("no %s keyring: %d\n", keyring_name[id], err);
keyring[id] = NULL;
return ERR_PTR(err);
}
}
return keyring[id];
}
int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
const char *digest, int digestlen)
{
struct key *keyring;
if (siglen < 2)
return -EINVAL;
keyring = integrity_keyring_from_id(id);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
switch (sig[1]) {
case 1:
/* v1 API expect signature without xattr type */
return digsig_verify(keyring, sig + 1, siglen - 1, digest,
digestlen);
case 2: /* regular file data hash based signature */
case 3: /* struct ima_file_id data based signature */
return asymmetric_verify(keyring, sig, siglen, digest,
digestlen);
}
return -EOPNOTSUPP;
}
int integrity_modsig_verify(const unsigned int id, const struct modsig *modsig)
{
struct key *keyring;
keyring = integrity_keyring_from_id(id);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
return ima_modsig_verify(keyring, modsig);
}
static int __init __integrity_init_keyring(const unsigned int id,
key_perm_t perm,
struct key_restriction *restriction)
{
const struct cred *cred = current_cred();
int err = 0;
keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
KGIDT_INIT(0), cred, perm,
KEY_ALLOC_NOT_IN_QUOTA, restriction, NULL);
if (IS_ERR(keyring[id])) {
err = PTR_ERR(keyring[id]);
pr_info("Can't allocate %s keyring (%d)\n",
keyring_name[id], err);
keyring[id] = NULL;
} else {
if (id == INTEGRITY_KEYRING_PLATFORM)
set_platform_trusted_keys(keyring[id]);
if (id == INTEGRITY_KEYRING_MACHINE && imputed_trust_enabled())
set_machine_trusted_keys(keyring[id]);
if (id == INTEGRITY_KEYRING_IMA)
load_module_cert(keyring[id]);
}
return err;
}
int __init integrity_init_keyring(const unsigned int id)
{
struct key_restriction *restriction;
key_perm_t perm;
int ret;
perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
| KEY_USR_READ | KEY_USR_SEARCH;
if (id == INTEGRITY_KEYRING_PLATFORM ||
(id == INTEGRITY_KEYRING_MACHINE &&
!IS_ENABLED(CONFIG_INTEGRITY_CA_MACHINE_KEYRING))) {
restriction = NULL;
goto out;
}
if (!IS_ENABLED(CONFIG_INTEGRITY_TRUSTED_KEYRING))
return 0;
restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
if (!restriction)
return -ENOMEM;
if (id == INTEGRITY_KEYRING_MACHINE)
restriction->check = restrict_link_by_ca;
else
restriction->check = restrict_link_to_ima;
/*
* MOK keys can only be added through a read-only runtime services
* UEFI variable during boot. No additional keys shall be allowed to
* load into the machine keyring following init from userspace.
*/
if (id != INTEGRITY_KEYRING_MACHINE)
perm |= KEY_USR_WRITE;
out:
ret = __integrity_init_keyring(id, perm, restriction);
if (ret)
kfree(restriction);
return ret;
}
static int __init integrity_add_key(const unsigned int id, const void *data,
off_t size, key_perm_t perm)
{
key_ref_t key;
int rc = 0;
if (!keyring[id])
return -EINVAL;
key = key_create_or_update(make_key_ref(keyring[id], 1), "asymmetric",
NULL, data, size, perm,
KEY_ALLOC_NOT_IN_QUOTA);
if (IS_ERR(key)) {
rc = PTR_ERR(key);
pr_err("Problem loading X.509 certificate %d\n", rc);
} else {
pr_notice("Loaded X.509 cert '%s'\n",
key_ref_to_ptr(key)->description);
key_ref_put(key);
}
return rc;
}
int __init integrity_load_x509(const unsigned int id, const char *path)
{
void *data = NULL;
size_t size;
int rc;
key_perm_t perm;
rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
READING_X509_CERTIFICATE);
if (rc < 0) {
pr_err("Unable to open file: %s (%d)", path, rc);
return rc;
}
size = rc;
perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ;
pr_info("Loading X.509 certificate: %s\n", path);
rc = integrity_add_key(id, (const void *)data, size, perm);
vfree(data);
return rc;
}
int __init integrity_load_cert(const unsigned int id, const char *source,
const void *data, size_t len, key_perm_t perm)
{
if (!data)
return -EINVAL;
pr_info("Loading X.509 certificate: %s\n", source);
return integrity_add_key(id, data, len, perm);
}
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