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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2021 Pengutronix, Ahmad Fatoum <kernel@pengutronix.de>
* Copyright 2025 NXP
*/
#include <keys/trusted_caam.h>
#include <keys/trusted-type.h>
#include <linux/build_bug.h>
#include <linux/key-type.h>
#include <linux/parser.h>
#include <soc/fsl/caam-blob.h>
static struct caam_blob_priv *blobifier;
#define KEYMOD "SECURE_KEY"
static_assert(MAX_KEY_SIZE + CAAM_BLOB_OVERHEAD <= CAAM_BLOB_MAX_LEN);
static_assert(MAX_BLOB_SIZE <= CAAM_BLOB_MAX_LEN);
enum {
opt_err,
opt_key_enc_algo,
};
static const match_table_t key_tokens = {
{opt_key_enc_algo, "key_enc_algo=%s"},
{opt_err, NULL}
};
#ifdef CAAM_DEBUG
static inline void dump_options(const struct caam_pkey_info *pkey_info)
{
pr_info("key encryption algo %d\n", pkey_info->key_enc_algo);
}
#else
static inline void dump_options(const struct caam_pkey_info *pkey_info)
{
}
#endif
static int get_pkey_options(char *c,
struct caam_pkey_info *pkey_info)
{
substring_t args[MAX_OPT_ARGS];
unsigned long token_mask = 0;
u16 key_enc_algo;
char *p = c;
int token;
int res;
if (!c)
return 0;
while ((p = strsep(&c, " \t"))) {
if (*p == '\0' || *p == ' ' || *p == '\t')
continue;
token = match_token(p, key_tokens, args);
if (test_and_set_bit(token, &token_mask))
return -EINVAL;
switch (token) {
case opt_key_enc_algo:
res = kstrtou16(args[0].from, 16, &key_enc_algo);
if (res < 0)
return -EINVAL;
pkey_info->key_enc_algo = key_enc_algo;
break;
default:
return -EINVAL;
}
}
return 0;
}
static bool is_key_pkey(char **datablob)
{
char *c = NULL;
do {
/* Second argument onwards,
* determine if tied to HW
*/
c = strsep(datablob, " \t");
if (c && (strcmp(c, "pk") == 0))
return true;
} while (c);
return false;
}
static int trusted_caam_seal(struct trusted_key_payload *p, char *datablob)
{
int ret;
struct caam_blob_info info = {
.input = p->key, .input_len = p->key_len,
.output = p->blob, .output_len = MAX_BLOB_SIZE,
.key_mod = KEYMOD, .key_mod_len = sizeof(KEYMOD) - 1,
};
/*
* If it is to be treated as protected key,
* read next arguments too.
*/
if (is_key_pkey(&datablob)) {
info.pkey_info.plain_key_sz = p->key_len;
info.pkey_info.is_pkey = 1;
ret = get_pkey_options(datablob, &info.pkey_info);
if (ret < 0)
return 0;
dump_options(&info.pkey_info);
}
ret = caam_encap_blob(blobifier, &info);
if (ret)
return ret;
p->blob_len = info.output_len;
if (info.pkey_info.is_pkey) {
p->key_len = p->blob_len + sizeof(struct caam_pkey_info);
memcpy(p->key, &info.pkey_info, sizeof(struct caam_pkey_info));
memcpy(p->key + sizeof(struct caam_pkey_info), p->blob, p->blob_len);
}
return 0;
}
static int trusted_caam_unseal(struct trusted_key_payload *p, char *datablob)
{
int ret;
struct caam_blob_info info = {
.input = p->blob, .input_len = p->blob_len,
.output = p->key, .output_len = MAX_KEY_SIZE,
.key_mod = KEYMOD, .key_mod_len = sizeof(KEYMOD) - 1,
};
if (is_key_pkey(&datablob)) {
info.pkey_info.plain_key_sz = p->blob_len - CAAM_BLOB_OVERHEAD;
info.pkey_info.is_pkey = 1;
ret = get_pkey_options(datablob, &info.pkey_info);
if (ret < 0)
return 0;
dump_options(&info.pkey_info);
p->key_len = p->blob_len + sizeof(struct caam_pkey_info);
memcpy(p->key, &info.pkey_info, sizeof(struct caam_pkey_info));
memcpy(p->key + sizeof(struct caam_pkey_info), p->blob, p->blob_len);
return 0;
}
ret = caam_decap_blob(blobifier, &info);
if (ret)
return ret;
p->key_len = info.output_len;
return 0;
}
static int trusted_caam_init(void)
{
int ret;
blobifier = caam_blob_gen_init();
if (IS_ERR(blobifier))
return PTR_ERR(blobifier);
ret = register_key_type(&key_type_trusted);
if (ret)
caam_blob_gen_exit(blobifier);
return ret;
}
static void trusted_caam_exit(void)
{
unregister_key_type(&key_type_trusted);
caam_blob_gen_exit(blobifier);
}
struct trusted_key_ops trusted_key_caam_ops = {
.migratable = 0, /* non-migratable */
.init = trusted_caam_init,
.seal = trusted_caam_seal,
.unseal = trusted_caam_unseal,
.exit = trusted_caam_exit,
};
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