oscore_context.h

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/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 
/*
 * Copyright (c) 2018, SICS, RISE AB
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 */
 
#ifndef _OSCORE_CONTEXT_H
#define _OSCORE_CONTEXT_H
 
#include "coap3/coap_uthash_internal.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define CONTEXT_KEY_LEN         16
#define TOKEN_SEQ_NUM           2  /* to be set by application */
#define EP_CTX_NUM              10 /* to be set by application */
#define CONTEXT_INIT_VECT_LEN   13
#define CONTEXT_SEQ_LEN         sizeof(uint64_t)
 
#define ED25519_PRIVATE_KEY_LEN 32
#define ED25519_PUBLIC_KEY_LEN  32
#define ED25519_SEED_LEN        32
#define ED25519_SIGNATURE_LEN   64
 
#define OSCORE_SEQ_MAX (((uint64_t)1 << 40) - 1)
 
typedef enum {
  OSCORE_MODE_SINGLE = 0, 
  OSCORE_MODE_GROUP,      
  OSCORE_MODE_PAIRWISE    
} oscore_mode_t;
 
typedef struct oscore_sender_ctx_t oscore_sender_ctx_t;
typedef struct oscore_recipient_ctx_t oscore_recipient_ctx_t;
typedef struct oscore_association_t oscore_association_t;
 
struct oscore_ctx_t {
  /* RFC8613 3.1 */
  cose_alg_t aead_alg;             
  cose_hkdf_alg_t hkdf_alg;        
  struct oscore_ctx_t *next;
  coap_bin_const_t *master_secret;
  coap_bin_const_t *master_salt;
  coap_bin_const_t *id_context; 
  coap_bin_const_t *common_iv;  
  oscore_sender_ctx_t *sender_context;
  oscore_recipient_ctx_t *recipient_chain;
  /* RFC8613 B.1.2 */
  uint8_t rfc8613_b_1_2; 
  /* RFC8613 B.2 */
  uint8_t rfc8613_b_2;   
  uint32_t replay_window_size;
  /* Tracking */
  uint32_t ssn_freq;     
  coap_oscore_save_seq_num_t save_seq_num_func; 
  void *save_seq_num_func_param; 
};
 
struct oscore_sender_ctx_t {
  /* RFC8613 3.1 */
  coap_bin_const_t *sender_id;
  coap_bin_const_t *sender_key;
  uint64_t seq;            
  /* Tracking */
  uint64_t next_seq; 
};
 
struct oscore_recipient_ctx_t {
  /* This field allows recipient chaining */
  oscore_recipient_ctx_t *next_recipient;
  oscore_ctx_t *osc_ctx;
  /* RFC8613 3.1 */
  coap_bin_const_t *recipient_id;
  coap_bin_const_t *recipient_key;
  uint64_t last_seq;
  /*  uint64_t highest_seq; */
  uint64_t sliding_window;
  uint64_t rollback_sliding_window;
  uint64_t rollback_last_seq;
  uint8_t echo_value[8];
  uint8_t initial_state;
  uint8_t silent_server;
};
 
#define OSCORE_ASSOCIATIONS_ADD(r, obj)                                        \
  HASH_ADD(hh, (r), token->s[0], (obj)->token->length, (obj))
 
#define OSCORE_ASSOCIATIONS_DELETE(r, obj) HASH_DELETE(hh, (r), (obj))
 
#define OSCORE_ASSOCIATIONS_ITER(r, tmp)                                       \
  oscore_associations_t *tmp, *rtmp;                                           \
  HASH_ITER (hh, (r), tmp, rtmp)
 
#define OSCORE_ASSOCIATIONS_ITER_SAFE(e, el, rtmp)                             \
  for ((el) = (e); (el) && ((rtmp) = (el)->hh.next, 1); (el) = (rtmp))
 
#define OSCORE_ASSOCIATIONS_FIND(r, k, res)                                    \
  { HASH_FIND(hh, (r), (k)->s, (k)->length, (res)); }
 
struct oscore_association_t {
  UT_hash_handle hh;
  oscore_recipient_ctx_t *recipient_ctx;
  coap_pdu_t *sent_pdu;
  coap_bin_const_t *token;
  coap_bin_const_t *aad;
  coap_bin_const_t *nonce;
  coap_bin_const_t *partial_iv;
  coap_bin_const_t *obs_partial_iv;
  coap_tick_t last_seen;
  uint8_t is_observe;
  uint8_t just_set_up;
};
 
oscore_ctx_t *oscore_derive_ctx(coap_context_t *c_context,
                                coap_oscore_conf_t *oscore_conf);
 
oscore_ctx_t *oscore_duplicate_ctx(coap_context_t *c_context,
                                   oscore_ctx_t *o_osc_ctx,
                                   coap_bin_const_t *sender_id,
                                   coap_bin_const_t *recipient_id,
                                   coap_bin_const_t *id_context);
 
void oscore_update_ctx(oscore_ctx_t *osc_ctx, coap_bin_const_t *id_context);
 
void oscore_free_context(oscore_ctx_t *osc_ctx);
 
void oscore_free_contexts(coap_context_t *c_context);
 
int oscore_remove_context(coap_context_t *c_context, oscore_ctx_t *osc_ctx);
 
oscore_recipient_ctx_t *oscore_add_recipient(oscore_ctx_t *ctx,
                                             coap_oscore_rcp_conf_t *rcp_conf,
                                             uint32_t break_key);
 
int oscore_delete_recipient(oscore_ctx_t *osc_ctx, coap_bin_const_t *rid);
 
void oscore_free_sender(oscore_sender_ctx_t *snd_ctx);
 
uint8_t oscore_bytes_equal(uint8_t *a_ptr,
                           uint8_t a_len,
                           uint8_t *b_ptr,
                           uint8_t b_len);
 
void oscore_convert_to_hex(const uint8_t *src,
                           size_t src_len,
                           char *dest,
                           size_t dst_len);
 
void oscore_log_hex_value(coap_log_t level,
                          const char *name,
                          coap_bin_const_t *value);
 
void oscore_log_int_value(coap_log_t level, const char *name, int value);
 
void oscore_log_char_value(coap_log_t level, const char *name,
                           const char *value);
 
oscore_ctx_t *oscore_find_context(const coap_session_t *session,
                                  const coap_bin_const_t rcpkey_id,
                                  const coap_bin_const_t *ctxkey_id,
                                  uint8_t *oscore_r2,
                                  oscore_recipient_ctx_t **recipient_ctx);
 
void oscore_free_association(oscore_association_t *association);
 
int oscore_new_association(coap_session_t *session,
                           coap_pdu_t *sent_pdu,
                           coap_bin_const_t *token,
                           oscore_recipient_ctx_t *recipient_ctx,
                           coap_bin_const_t *aad,
                           coap_bin_const_t *nonce,
                           coap_bin_const_t *partial_iv,
                           int is_observe);
 
oscore_association_t *oscore_find_association(coap_session_t *session,
                                              coap_bin_const_t *token);
 
int oscore_delete_association(coap_session_t *session,
                              oscore_association_t *association);
 
void oscore_delete_server_associations(coap_session_t *session);
 
int oscore_derive_keystream(oscore_ctx_t *osc_ctx,
                            cose_encrypt0_t *code,
                            uint8_t coap_request,
                            coap_bin_const_t *sender_key,
                            coap_bin_const_t *id_context,
                            size_t cs_size,
                            uint8_t *keystream,
                            size_t keystream_size);
 
coap_bin_const_t *oscore_build_key(oscore_ctx_t *osc_ctx,
                                   coap_bin_const_t *salt,
                                   coap_bin_const_t *ikm,
                                   cose_alg_t aead_alg,
                                   coap_bin_const_t *id,
                                   coap_str_const_t *type,
                                   size_t out_len);
 
#ifdef __cplusplus
}
#endif
 
#endif /* _OSCORE_CONTEXT_H */