398 lines
9.2 KiB
C
398 lines
9.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2010 IBM Corporation
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* Copyright (c) 2019-2021, Linaro Limited
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*
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* See Documentation/security/keys/trusted-encrypted.rst
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*/
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#include <keys/user-type.h>
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#include <keys/trusted-type.h>
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#include <keys/trusted_tee.h>
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#include <keys/trusted_caam.h>
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#include <keys/trusted_tpm.h>
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#include <linux/capability.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/key-type.h>
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#include <linux/module.h>
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#include <linux/parser.h>
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#include <linux/random.h>
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#include <linux/rcupdate.h>
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#include <linux/slab.h>
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#include <linux/static_call.h>
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#include <linux/string.h>
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#include <linux/uaccess.h>
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static char *trusted_rng = "default";
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module_param_named(rng, trusted_rng, charp, 0);
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MODULE_PARM_DESC(rng, "Select trusted key RNG");
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static char *trusted_key_source;
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module_param_named(source, trusted_key_source, charp, 0);
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MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee or caam)");
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static const struct trusted_key_source trusted_key_sources[] = {
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#if defined(CONFIG_TRUSTED_KEYS_TPM)
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{ "tpm", &trusted_key_tpm_ops },
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#endif
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#if defined(CONFIG_TRUSTED_KEYS_TEE)
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{ "tee", &trusted_key_tee_ops },
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#endif
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#if defined(CONFIG_TRUSTED_KEYS_CAAM)
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{ "caam", &trusted_key_caam_ops },
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#endif
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};
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DEFINE_STATIC_CALL_NULL(trusted_key_init, *trusted_key_sources[0].ops->init);
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DEFINE_STATIC_CALL_NULL(trusted_key_seal, *trusted_key_sources[0].ops->seal);
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DEFINE_STATIC_CALL_NULL(trusted_key_unseal,
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*trusted_key_sources[0].ops->unseal);
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DEFINE_STATIC_CALL_NULL(trusted_key_get_random,
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*trusted_key_sources[0].ops->get_random);
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DEFINE_STATIC_CALL_NULL(trusted_key_exit, *trusted_key_sources[0].ops->exit);
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static unsigned char migratable;
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enum {
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Opt_err,
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Opt_new, Opt_load, Opt_update,
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};
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static const match_table_t key_tokens = {
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{Opt_new, "new"},
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{Opt_load, "load"},
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{Opt_update, "update"},
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{Opt_err, NULL}
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};
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/*
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* datablob_parse - parse the keyctl data and fill in the
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* payload structure
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*
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* On success returns 0, otherwise -EINVAL.
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*/
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static int datablob_parse(char **datablob, struct trusted_key_payload *p)
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{
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substring_t args[MAX_OPT_ARGS];
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long keylen;
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int ret = -EINVAL;
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int key_cmd;
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char *c;
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/* main command */
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c = strsep(datablob, " \t");
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if (!c)
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return -EINVAL;
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key_cmd = match_token(c, key_tokens, args);
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switch (key_cmd) {
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case Opt_new:
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/* first argument is key size */
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c = strsep(datablob, " \t");
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if (!c)
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return -EINVAL;
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ret = kstrtol(c, 10, &keylen);
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if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
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return -EINVAL;
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p->key_len = keylen;
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ret = Opt_new;
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break;
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case Opt_load:
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/* first argument is sealed blob */
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c = strsep(datablob, " \t");
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if (!c)
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return -EINVAL;
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p->blob_len = strlen(c) / 2;
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if (p->blob_len > MAX_BLOB_SIZE)
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return -EINVAL;
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ret = hex2bin(p->blob, c, p->blob_len);
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if (ret < 0)
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return -EINVAL;
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ret = Opt_load;
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break;
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case Opt_update:
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ret = Opt_update;
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break;
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case Opt_err:
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return -EINVAL;
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}
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return ret;
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}
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static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
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{
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struct trusted_key_payload *p = NULL;
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int ret;
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ret = key_payload_reserve(key, sizeof(*p));
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if (ret < 0)
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goto err;
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p = kzalloc(sizeof(*p), GFP_KERNEL);
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if (!p)
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goto err;
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p->migratable = migratable;
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err:
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return p;
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}
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/*
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* trusted_instantiate - create a new trusted key
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*
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* Unseal an existing trusted blob or, for a new key, get a
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* random key, then seal and create a trusted key-type key,
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* adding it to the specified keyring.
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*
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* On success, return 0. Otherwise return errno.
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*/
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static int trusted_instantiate(struct key *key,
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struct key_preparsed_payload *prep)
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{
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struct trusted_key_payload *payload = NULL;
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size_t datalen = prep->datalen;
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char *datablob, *orig_datablob;
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int ret = 0;
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int key_cmd;
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size_t key_len;
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if (datalen <= 0 || datalen > 32767 || !prep->data)
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return -EINVAL;
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orig_datablob = datablob = kmalloc(datalen + 1, GFP_KERNEL);
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if (!datablob)
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return -ENOMEM;
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memcpy(datablob, prep->data, datalen);
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datablob[datalen] = '\0';
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payload = trusted_payload_alloc(key);
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if (!payload) {
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ret = -ENOMEM;
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goto out;
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}
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key_cmd = datablob_parse(&datablob, payload);
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if (key_cmd < 0) {
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ret = key_cmd;
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goto out;
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}
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dump_payload(payload);
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switch (key_cmd) {
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case Opt_load:
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ret = static_call(trusted_key_unseal)(payload, datablob);
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dump_payload(payload);
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if (ret < 0)
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pr_info("key_unseal failed (%d)\n", ret);
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break;
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case Opt_new:
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key_len = payload->key_len;
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ret = static_call(trusted_key_get_random)(payload->key,
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key_len);
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if (ret < 0)
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goto out;
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if (ret != key_len) {
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pr_info("key_create failed (%d)\n", ret);
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ret = -EIO;
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goto out;
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}
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ret = static_call(trusted_key_seal)(payload, datablob);
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if (ret < 0)
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pr_info("key_seal failed (%d)\n", ret);
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break;
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default:
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ret = -EINVAL;
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}
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out:
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kfree_sensitive(orig_datablob);
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if (!ret)
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rcu_assign_keypointer(key, payload);
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else
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kfree_sensitive(payload);
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return ret;
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}
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static void trusted_rcu_free(struct rcu_head *rcu)
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{
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struct trusted_key_payload *p;
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p = container_of(rcu, struct trusted_key_payload, rcu);
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kfree_sensitive(p);
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}
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/*
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* trusted_update - reseal an existing key with new PCR values
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*/
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static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
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{
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struct trusted_key_payload *p;
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struct trusted_key_payload *new_p;
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size_t datalen = prep->datalen;
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char *datablob, *orig_datablob;
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int ret = 0;
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if (key_is_negative(key))
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return -ENOKEY;
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p = key->payload.data[0];
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if (!p->migratable)
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return -EPERM;
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if (datalen <= 0 || datalen > 32767 || !prep->data)
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return -EINVAL;
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orig_datablob = datablob = kmalloc(datalen + 1, GFP_KERNEL);
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if (!datablob)
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return -ENOMEM;
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new_p = trusted_payload_alloc(key);
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if (!new_p) {
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ret = -ENOMEM;
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goto out;
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}
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memcpy(datablob, prep->data, datalen);
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datablob[datalen] = '\0';
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ret = datablob_parse(&datablob, new_p);
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if (ret != Opt_update) {
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ret = -EINVAL;
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kfree_sensitive(new_p);
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goto out;
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}
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/* copy old key values, and reseal with new pcrs */
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new_p->migratable = p->migratable;
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new_p->key_len = p->key_len;
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memcpy(new_p->key, p->key, p->key_len);
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dump_payload(p);
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dump_payload(new_p);
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ret = static_call(trusted_key_seal)(new_p, datablob);
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if (ret < 0) {
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pr_info("key_seal failed (%d)\n", ret);
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kfree_sensitive(new_p);
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goto out;
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}
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rcu_assign_keypointer(key, new_p);
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call_rcu(&p->rcu, trusted_rcu_free);
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out:
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kfree_sensitive(orig_datablob);
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return ret;
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}
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/*
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* trusted_read - copy the sealed blob data to userspace in hex.
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* On success, return to userspace the trusted key datablob size.
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*/
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static long trusted_read(const struct key *key, char *buffer,
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size_t buflen)
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{
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const struct trusted_key_payload *p;
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char *bufp;
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int i;
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p = dereference_key_locked(key);
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if (!p)
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return -EINVAL;
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if (buffer && buflen >= 2 * p->blob_len) {
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bufp = buffer;
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for (i = 0; i < p->blob_len; i++)
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bufp = hex_byte_pack(bufp, p->blob[i]);
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}
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return 2 * p->blob_len;
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}
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/*
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* trusted_destroy - clear and free the key's payload
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*/
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static void trusted_destroy(struct key *key)
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{
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kfree_sensitive(key->payload.data[0]);
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}
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struct key_type key_type_trusted = {
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.name = "trusted",
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.instantiate = trusted_instantiate,
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.update = trusted_update,
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.destroy = trusted_destroy,
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.describe = user_describe,
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.read = trusted_read,
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};
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EXPORT_SYMBOL_GPL(key_type_trusted);
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static int kernel_get_random(unsigned char *key, size_t key_len)
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{
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return get_random_bytes_wait(key, key_len) ?: key_len;
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}
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static int __init init_trusted(void)
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{
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int (*get_random)(unsigned char *key, size_t key_len);
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int i, ret = 0;
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for (i = 0; i < ARRAY_SIZE(trusted_key_sources); i++) {
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if (trusted_key_source &&
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strncmp(trusted_key_source, trusted_key_sources[i].name,
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strlen(trusted_key_sources[i].name)))
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continue;
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/*
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* We always support trusted.rng="kernel" and "default" as
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* well as trusted.rng=$trusted.source if the trust source
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* defines its own get_random callback.
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*/
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get_random = trusted_key_sources[i].ops->get_random;
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if (trusted_rng && strcmp(trusted_rng, "default")) {
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if (!strcmp(trusted_rng, "kernel")) {
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get_random = kernel_get_random;
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} else if (strcmp(trusted_rng, trusted_key_sources[i].name) ||
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!get_random) {
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pr_warn("Unsupported RNG. Supported: kernel");
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if (get_random)
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pr_cont(", %s", trusted_key_sources[i].name);
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pr_cont(", default\n");
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return -EINVAL;
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}
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}
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if (!get_random)
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get_random = kernel_get_random;
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static_call_update(trusted_key_init,
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trusted_key_sources[i].ops->init);
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static_call_update(trusted_key_seal,
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trusted_key_sources[i].ops->seal);
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static_call_update(trusted_key_unseal,
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trusted_key_sources[i].ops->unseal);
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static_call_update(trusted_key_get_random,
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get_random);
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static_call_update(trusted_key_exit,
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trusted_key_sources[i].ops->exit);
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migratable = trusted_key_sources[i].ops->migratable;
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ret = static_call(trusted_key_init)();
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if (!ret)
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break;
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}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* encrypted_keys.ko depends on successful load of this module even if
|
||
|
|
* trusted key implementation is not found.
|
||
|
|
*/
|
||
|
|
if (ret == -ENODEV)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit cleanup_trusted(void)
|
||
|
|
{
|
||
|
|
static_call_cond(trusted_key_exit)();
|
||
|
|
}
|
||
|
|
|
||
|
|
late_initcall(init_trusted);
|
||
|
|
module_exit(cleanup_trusted);
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL");
|