diff options
Diffstat (limited to 'security/keys/trusted-keys/trusted_caam.c')
| -rw-r--r-- | security/keys/trusted-keys/trusted_caam.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/security/keys/trusted-keys/trusted_caam.c b/security/keys/trusted-keys/trusted_caam.c new file mode 100644 index 000000000000..601943ce0d60 --- /dev/null +++ b/security/keys/trusted-keys/trusted_caam.c @@ -0,0 +1,188 @@ +// 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, +}; |