Contiki-NG: Crypto adapter for OSCORE

include/coap3/coap_internal.h

@@ -85,6 +85,11 @@
 /*
  * Include all the header files that are for internal use only.
  */
+#if COAP_OSCORE_SUPPORT && defined(WITH_CONTIKI)
+#include "lib/aes-128.h"
+#include "lib/ccm-star.h"
+#include "lib/sha-256.h"
+#endif /*COAP_OSCORE_SUPPORT && WITH_CONTIKI */
 
 #if defined(COAP_OSCORE_SUPPORT) || defined(COAP_WS_SUPPORT)
 /* Specific OSCORE general .h files */

src/coap_gnutls.c

@@ -3006,7 +3006,7 @@ coap_crypto_hash(cose_alg_t alg,
 }
 #endif /* COAP_WS_SUPPORT */
 
-#if COAP_OSCORE_SUPPORT
+#if COAP_OSCORE_SUPPORT && !defined(WITH_CONTIKI)
 int
 coap_oscore_is_supported(void) {
   return 1;
@@ -3240,7 +3240,7 @@ coap_crypto_hmac(cose_hmac_alg_t hmac_alg,
   return ret == 1 ? 1 : 0;
 }
 
-#endif /* COAP_OSCORE_SUPPORT */
+#endif /* COAP_OSCORE_SUPPORT && !WITH_CONTIKI */
 
 #else /* !COAP_WITH_LIBGNUTLS */
 

src/coap_mbedtls.c

@@ -2708,7 +2708,7 @@ coap_crypto_hash(cose_alg_t alg,
 }
 #endif /* COAP_WS_SUPPORT */
 
-#if COAP_OSCORE_SUPPORT
+#if COAP_OSCORE_SUPPORT && !defined(WITH_CONTIKI)
 int
 coap_oscore_is_supported(void) {
   return 1;
@@ -3036,7 +3036,7 @@ coap_crypto_hmac(cose_hmac_alg_t hmac_alg,
   return ret;
 }
 
-#endif /* COAP_OSCORE_SUPPORT */
+#endif /* COAP_OSCORE_SUPPORT && !WITH_CONTIKI */
 
 #else /* !COAP_WITH_LIBMBEDTLS */
 

src/coap_notls.c

@@ -339,7 +339,7 @@ coap_crypto_hash(cose_alg_t alg,
 }
 #endif /* COAP_WS_SUPPORT */
 
-#if COAP_OSCORE_SUPPORT
+#if COAP_OSCORE_SUPPORT && !defined(WITH_CONTIKI)
 
 int
 coap_oscore_is_supported(void) {
@@ -398,7 +398,7 @@ coap_crypto_hmac(cose_hmac_alg_t hmac_alg,
   return 0;
 }
 
-#endif /* COAP_OSCORE_SUPPORT */
+#endif /* COAP_OSCORE_SUPPORT && !WITH_CONTIKI */
 
 #else /* !COAP_WITH_LIBTINYDTLS && !COAP_WITH_LIBOPENSSL && !COAP_WITH_LIBGNUTLS */
 

src/coap_openssl.c

@@ -3702,7 +3702,7 @@ coap_crypto_hash(cose_alg_t alg,
 }
 #endif /* COAP_WS_SUPPORT */
 
-#if COAP_OSCORE_SUPPORT
+#if COAP_OSCORE_SUPPORT && !defined(WITH_CONTIKI)
 int
 coap_oscore_is_supported(void) {
   return 1;
@@ -3939,7 +3939,7 @@ coap_crypto_hmac(cose_hmac_alg_t hmac_alg,
   return 0;
 }
 
-#endif /* COAP_OSCORE_SUPPORT */
+#endif /* COAP_OSCORE_SUPPORT && !WITH_CONTIKI */
 
 #else /* !COAP_WITH_LIBOPENSSL */
 

src/coap_tinydtls.c

@@ -1510,7 +1510,7 @@ coap_crypto_hash(cose_alg_t alg,
 }
 #endif /* COAP_WS_SUPPORT */
 
-#if COAP_OSCORE_SUPPORT
+#if COAP_OSCORE_SUPPORT && !defined(WITH_CONTIKI)
 
 int
 coap_oscore_is_supported(void) {
@@ -1711,7 +1711,7 @@ coap_crypto_hmac(cose_hmac_alg_t hmac_alg, coap_bin_const_t *key,
   return 1;
 }
 
-#endif /* COAP_OSCORE_SUPPORT */
+#endif /* COAP_OSCORE_SUPPORT && !WITH_CONTIKI */
 
 #else /* !COAP_WITH_LIBTINYDTLS */
 

src/oscore/oscore_crypto_contiki.c

@@ -0,0 +1,138 @@
+/* oscore_crypto_contiki.c -- Crypto adapter for Contiki-NG
+ *
+ * Copyright (C) 2023 Uppsala universitet
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * This file is part of the CoAP library libcoap. Please see
+ * README for terms of use.
+ */
+
+/**
+ * @file oscore_crypto_contiki.c
+ * @brief Crypto adapter for Contiki-NG
+ */
+
+#include "coap3/coap_internal.h"
+#include <string.h>
+#include <sys/types.h>
+
+int
+coap_oscore_is_supported(void) {
+  return 1;
+}
+
+int
+coap_crypto_check_cipher_alg(cose_alg_t alg) {
+  switch (alg) {
+  case COSE_ALGORITHM_AES_CCM_16_64_128:
+  case COSE_ALGORITHM_AES_CCM_16_128_128:
+    return 1;
+  default:
+    return 0;
+  }
+}
+
+int
+coap_crypto_check_hkdf_alg(cose_hkdf_alg_t hkdf_alg) {
+  return hkdf_alg == COSE_HKDF_ALG_HKDF_SHA_256;
+}
+
+int
+coap_crypto_aead_encrypt(const coap_crypto_param_t *params,
+                         coap_bin_const_t *data,
+                         coap_bin_const_t *aad,
+                         uint8_t *result,
+                         size_t *max_result_len) {
+  /* validate inputs */
+  assert(params->params.aes.tag_len <= AES_128_BLOCK_SIZE);
+  if ((data->length > UINT16_MAX) || (aad->length > UINT16_MAX)) {
+    return 0;
+  }
+  size_t result_len = data->length + params->params.aes.tag_len;
+  if (*max_result_len < result_len) {
+    return 0;
+  }
+
+  /* set max_result_len */
+  *max_result_len = result_len;
+
+  /* copy plaintext */
+  memcpy(result, data->s, data->length);
+
+  /* encrypt */
+  while (!AES_128.get_lock());
+  if (!CCM_STAR.set_key(params->params.key.s)) {
+    return 0;
+  }
+  if (!CCM_STAR.aead(params->params.aes.nonce,
+                     result, data->length,
+                     aad->s, aad->length,
+                     result + data->length, params->params.aes.tag_len,
+                     true)) {
+    return 0;
+  }
+  AES_128.release_lock();
+
+  return 1;
+}
+
+int
+coap_crypto_aead_decrypt(const coap_crypto_param_t *params,
+                         coap_bin_const_t *data,
+                         coap_bin_const_t *aad,
+                         uint8_t *result,
+                         size_t *max_result_len) {
+  size_t result_len;
+  uint8_t expected_tag[AES_128_BLOCK_SIZE];
+
+  /* validate inputs */
+  assert(params->params.aes.tag_len <= AES_128_BLOCK_SIZE);
+  if (data->length < params->params.aes.tag_len) {
+    return 0;
+  }
+  result_len = data->length - params->params.aes.tag_len;
+  if (*max_result_len < result_len) {
+    return 0;
+  }
+  if ((result_len > UINT16_MAX) || (aad->length > UINT16_MAX)) {
+    return 0;
+  }
+
+  /* set max_result_len */
+  *max_result_len = result_len;
+
+  /* copy ciphertext */
+  memcpy(result, data->s, result_len);
+
+  /* decrypt */
+  while (!AES_128.get_lock());
+  if (!CCM_STAR.set_key(params->params.key.s)) {
+    return 0;
+  }
+  if (!CCM_STAR.aead(params->params.aes.nonce,
+                     result, result_len,
+                     aad->s, aad->length,
+                     expected_tag, params->params.aes.tag_len,
+                     false)) {
+    return 0;
+  }
+  AES_128.release_lock();
+
+  return !memcmp(expected_tag,
+                 data->s + result_len,
+                 params->params.aes.tag_len);
+}
+
+int
+coap_crypto_hmac(cose_hmac_alg_t hmac_alg,
+                 coap_bin_const_t *key,
+                 coap_bin_const_t *data,
+                 coap_bin_const_t **hmac) {
+  uint8_t hmac_bytes[SHA_256_DIGEST_LENGTH];
+
+  assert(hmac_alg == COSE_HMAC_ALG_HMAC256_256);
+  sha_256_hmac(key->s, key->length, data->s, data->length, hmac_bytes);
+  *hmac = coap_new_bin_const(hmac_bytes, sizeof(hmac_bytes));
+  return *hmac != NULL;
+}