diff options
Diffstat (limited to 'drivers/auth/mbedtls')
| -rw-r--r-- | drivers/auth/mbedtls/mbedtls_common.mk | 26 | ||||
| -rw-r--r-- | drivers/auth/mbedtls/mbedtls_crypto.c | 118 |
2 files changed, 135 insertions, 9 deletions
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk index 4b8301541..53ebe30b6 100644 --- a/drivers/auth/mbedtls/mbedtls_common.mk +++ b/drivers/auth/mbedtls/mbedtls_common.mk @@ -1,5 +1,5 @@ # -# Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved. +# Copyright (c) 2015-2020, Arm Limited. All rights reserved. # # SPDX-License-Identifier: BSD-3-Clause # @@ -23,15 +23,18 @@ MBEDTLS_SOURCES += drivers/auth/mbedtls/mbedtls_common.c LIBMBEDTLS_SRCS := $(addprefix ${MBEDTLS_DIR}/library/, \ + aes.c \ asn1parse.c \ asn1write.c \ + cipher.c \ + cipher_wrap.c \ memory_buffer_alloc.c \ oid.c \ platform.c \ platform_util.c \ bignum.c \ + gcm.c \ md.c \ - md_wrap.c \ pk.c \ pk_wrap.c \ pkparse.c \ @@ -72,7 +75,7 @@ endif ifeq (${HASH_ALG}, sha384) TF_MBEDTLS_HASH_ALG_ID := TF_MBEDTLS_SHA384 else ifeq (${HASH_ALG}, sha512) - TF_MBEDTLS_HASH_ALG_ID := TF_MBEDTLS_SHA512 + TF_MBEDTLS_HASH_ALG_ID := TF_MBEDTLS_SHA512 else TF_MBEDTLS_HASH_ALG_ID := TF_MBEDTLS_SHA256 endif @@ -87,11 +90,20 @@ else $(error "TF_MBEDTLS_KEY_ALG=${TF_MBEDTLS_KEY_ALG} not supported on mbed TLS") endif -# Needs to be set to drive mbed TLS configuration correctly -$(eval $(call add_define,TF_MBEDTLS_KEY_ALG_ID)) -$(eval $(call add_define,TF_MBEDTLS_KEY_SIZE)) -$(eval $(call add_define,TF_MBEDTLS_HASH_ALG_ID)) +ifeq (${DECRYPTION_SUPPORT}, aes_gcm) + TF_MBEDTLS_USE_AES_GCM := 1 +else + TF_MBEDTLS_USE_AES_GCM := 0 +endif +# Needs to be set to drive mbed TLS configuration correctly +$(eval $(call add_defines,\ + $(sort \ + TF_MBEDTLS_KEY_ALG_ID \ + TF_MBEDTLS_KEY_SIZE \ + TF_MBEDTLS_HASH_ALG_ID \ + TF_MBEDTLS_USE_AES_GCM \ +))) $(eval $(call MAKE_LIB,mbedtls)) diff --git a/drivers/auth/mbedtls/mbedtls_crypto.c b/drivers/auth/mbedtls/mbedtls_crypto.c index 04fbc648b..6d6efb503 100644 --- a/drivers/auth/mbedtls/mbedtls_crypto.c +++ b/drivers/auth/mbedtls/mbedtls_crypto.c @@ -4,19 +4,23 @@ * SPDX-License-Identifier: BSD-3-Clause */ +#include <assert.h> #include <stddef.h> #include <string.h> /* mbed TLS headers */ +#include <mbedtls/gcm.h> #include <mbedtls/md.h> #include <mbedtls/memory_buffer_alloc.h> #include <mbedtls/oid.h> #include <mbedtls/platform.h> +#include <mbedtls/x509.h> #include <common/debug.h> #include <drivers/auth/crypto_mod.h> #include <drivers/auth/mbedtls/mbedtls_common.h> #include <drivers/auth/mbedtls/mbedtls_config.h> +#include <plat/common/platform.h> #define LIB_NAME "mbed TLS" @@ -226,11 +230,121 @@ int calc_hash(unsigned int alg, void *data_ptr, } #endif /* MEASURED_BOOT */ +#if TF_MBEDTLS_USE_AES_GCM +/* + * Stack based buffer allocation for decryption operation. It could + * be configured to balance stack usage vs execution speed. + */ +#define DEC_OP_BUF_SIZE 128 + +static int aes_gcm_decrypt(void *data_ptr, size_t len, const void *key, + unsigned int key_len, const void *iv, + unsigned int iv_len, const void *tag, + unsigned int tag_len) +{ + mbedtls_gcm_context ctx; + mbedtls_cipher_id_t cipher = MBEDTLS_CIPHER_ID_AES; + unsigned char buf[DEC_OP_BUF_SIZE]; + unsigned char tag_buf[CRYPTO_MAX_TAG_SIZE]; + unsigned char *pt = data_ptr; + size_t dec_len; + int diff, i, rc; + + mbedtls_gcm_init(&ctx); + + rc = mbedtls_gcm_setkey(&ctx, cipher, key, key_len * 8); + if (rc != 0) { + rc = CRYPTO_ERR_DECRYPTION; + goto exit_gcm; + } + + rc = mbedtls_gcm_starts(&ctx, MBEDTLS_GCM_DECRYPT, iv, iv_len, NULL, 0); + if (rc != 0) { + rc = CRYPTO_ERR_DECRYPTION; + goto exit_gcm; + } + + while (len > 0) { + dec_len = MIN(sizeof(buf), len); + + rc = mbedtls_gcm_update(&ctx, dec_len, pt, buf); + if (rc != 0) { + rc = CRYPTO_ERR_DECRYPTION; + goto exit_gcm; + } + + memcpy(pt, buf, dec_len); + pt += dec_len; + len -= dec_len; + } + + rc = mbedtls_gcm_finish(&ctx, tag_buf, sizeof(tag_buf)); + if (rc != 0) { + rc = CRYPTO_ERR_DECRYPTION; + goto exit_gcm; + } + + /* Check tag in "constant-time" */ + for (diff = 0, i = 0; i < tag_len; i++) + diff |= ((const unsigned char *)tag)[i] ^ tag_buf[i]; + + if (diff != 0) { + rc = CRYPTO_ERR_DECRYPTION; + goto exit_gcm; + } + + /* GCM decryption success */ + rc = CRYPTO_SUCCESS; + +exit_gcm: + mbedtls_gcm_free(&ctx); + return rc; +} + +/* + * Authenticated decryption of an image + */ +static int auth_decrypt(enum crypto_dec_algo dec_algo, void *data_ptr, + size_t len, const void *key, unsigned int key_len, + unsigned int key_flags, const void *iv, + unsigned int iv_len, const void *tag, + unsigned int tag_len) +{ + int rc; + + assert((key_flags & ENC_KEY_IS_IDENTIFIER) == 0); + + switch (dec_algo) { + case CRYPTO_GCM_DECRYPT: + rc = aes_gcm_decrypt(data_ptr, len, key, key_len, iv, iv_len, + tag, tag_len); + if (rc != 0) + return rc; + break; + default: + return CRYPTO_ERR_DECRYPTION; + } + + return CRYPTO_SUCCESS; +} +#endif /* TF_MBEDTLS_USE_AES_GCM */ + /* * Register crypto library descriptor */ #if MEASURED_BOOT -REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash); +#if TF_MBEDTLS_USE_AES_GCM +REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash, + auth_decrypt); +#else +REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash, + NULL); +#endif +#else /* MEASURED_BOOT */ +#if TF_MBEDTLS_USE_AES_GCM +REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, + auth_decrypt); #else -REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash); +REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, NULL); +#endif #endif /* MEASURED_BOOT */ |