lws-jwe.h

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 /*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * JWE Compact Serialization consists of
 *
 *     BASE64URL(UTF8(JWE Protected Header)) || '.' ||
 *     BASE64URL(JWE Encrypted Key)          || '.' ||
 *     BASE64URL(JWE Initialization Vector)  || '.' ||
 *     BASE64URL(JWE Ciphertext)             || '.' ||
 *     BASE64URL(JWE Authentication Tag)
 */
 
#define LWS_JWE_RFC3394_OVERHEAD_BYTES 8
#define LWS_JWE_AES_IV_BYTES 16
 
#define LWS_JWE_LIMIT_RSA_KEY_BITS 4096
#define LWS_JWE_LIMIT_AES_KEY_BITS (512 + 64) /* RFC3394 Key Wrap adds 64b */
#define LWS_JWE_LIMIT_EC_KEY_BITS  528 /* 521 rounded to byte boundary */
#define LWS_JWE_LIMIT_HASH_BITS    (LWS_GENHASH_LARGEST * 8)
 
/* the largest key element for any cipher */
#define LWS_JWE_LIMIT_KEY_ELEMENT_BYTES (LWS_JWE_LIMIT_RSA_KEY_BITS / 8)
 
 
struct lws_jwe {
        struct lws_jose jose;
        struct lws_jws jws;
        struct lws_jwk jwk;
 
        /*
         * We have to keep a copy of the CEK so we can reuse it with later
         * key encryptions for the multiple recipient case.
         */
        uint8_t cek[LWS_JWE_LIMIT_KEY_ELEMENT_BYTES];
        unsigned int cek_valid:1;
 
        int recip;
};
 
LWS_VISIBLE LWS_EXTERN void
lws_jwe_init(struct lws_jwe *jwe, struct lws_context *context);
 
LWS_VISIBLE LWS_EXTERN void
lws_jwe_destroy(struct lws_jwe *jwe);
 
LWS_VISIBLE LWS_EXTERN void
lws_jwe_be64(uint64_t c, uint8_t *p8);
 
/*
 * JWE Compact Serialization consists of
 *
 *     BASE64URL(UTF8(JWE Protected Header)) || '.' ||
 *     BASE64URL(JWE Encrypted Key)          || '.' ||
 *     BASE64URL(JWE Initialization Vector)  || '.' ||
 *     BASE64URL(JWE Ciphertext)             || '.' ||
 *     BASE64URL(JWE Authentication Tag)
 */
 
LWS_VISIBLE LWS_EXTERN int
lws_jwe_render_compact(struct lws_jwe *jwe, char *out, size_t out_len);
 
LWS_VISIBLE int
lws_jwe_render_flattened(struct lws_jwe *jwe, char *out, size_t out_len);
 
LWS_VISIBLE LWS_EXTERN int
lws_jwe_json_parse(struct lws_jwe *jwe, const uint8_t *buf, int len,
                   char *temp, int *temp_len);

LWS_VISIBLE LWS_EXTERN int
lws_jwe_auth_and_decrypt(struct lws_jwe *jwe, char *temp, int *temp_len);

LWS_VISIBLE LWS_EXTERN int
lws_jwe_encrypt(struct lws_jwe *jwe, char *temp, int *temp_len);

LWS_VISIBLE LWS_EXTERN int
lws_jwe_create_packet(struct lws_jwe *jwe,
                      const char *payload, size_t len, const char *nonce,
                      char *out, size_t out_len, struct lws_context *context);
 
 
/* only exposed because we have test vectors that need it */
LWS_VISIBLE LWS_EXTERN int
lws_jwe_auth_and_decrypt_cbc_hs(struct lws_jwe *jwe, uint8_t *enc_cek,
                                        uint8_t *aad, int aad_len);
 
/* only exposed because we have test vectors that need it */
LWS_VISIBLE LWS_EXTERN int
lws_jwa_concat_kdf(struct lws_jwe *jwe, int direct,
                   uint8_t *out, const uint8_t *shared_secret, int sslen);