lws-cose.h

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/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 - 2021 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.
 */
 
/** \defgroup cose COSE apis
 * ##COSE related functions
 * \ingroup lwsaoi
 *
 * COSE RFC 8152 relates to signed and encrypted CBOR
 */
//@{
 
enum {
        /*  RFC8152: Table 2: Common Header Parameters
         * https://www.iana.org/assignments/cose/cose.xhtml#header-parameters
         */
 
        LWSCOSE_WKL_ALG                         = 1,   /* int / tstr */
        LWSCOSE_WKL_CRIT,                              /* [+ label ] */
        LWSCOSE_WKL_CONTENT_TYPE,                      /* tstr / uint */
        LWSCOSE_WKL_KID,                               /* bstr */
        LWSCOSE_WKL_IV,                                /* bstr */
        LWSCOSE_WKL_IV_PARTIAL,                        /* bstr */
        LWSCOSE_WKL_COUNTERSIG,                        /* COSE sig(s) */
        LWSCOSE_WKL_COUNTERSIG0                 = 9,   /* bstr */
        LWSCOSE_WKL_KID_CONTEXT,                       /* bstr */
        LWSCOSE_WKL_CUPH_NONCE                  = 256, /* bstr */
        LWSCOSE_WKL_CUPH_OWNER_PUBKEY           = 257, /* array */
 
        /*  RFC8152: Table 3: key map labels */
 
        LWSCOSE_WKK_KTY                         = 1, /* int / tstr */
        LWSCOSE_WKK_KID,                             /* bstr */
        LWSCOSE_WKK_ALG,                             /* int / tstr */
        LWSCOSE_WKK_KEY_OPS,                         /* [ + (int / tstr) ] */
        LWSCOSE_WKK_BASE_IV,                         /* bstr */
 
        /*  RFC8152: Table 4: Key Operation Values */
 
        LWSCOSE_WKKO_SIGN                       = 1,
        LWSCOSE_WKKO_VERIFY,
        LWSCOSE_WKKO_ENCRYPT,
        LWSCOSE_WKKO_DECRYPT,
        LWSCOSE_WKKO_WRAP_KEY,
        LWSCOSE_WKKO_UNWRAP_KEY,
        LWSCOSE_WKKO_DERIVE_KEY,
        LWSCOSE_WKKO_DERIVE_BITS,
        LWSCOSE_WKKO_MAC_CREATE,
        LWSCOSE_WKKO_MAC_VERIFY,
 
        /*  RFC8152: Table 5: ECDSA algs */
 
        LWSCOSE_WKAECDSA_ALG_ES256              = -7,
        LWSCOSE_WKAECDSA_ALG_ES384              = -35,
        LWSCOSE_WKAECDSA_ALG_ES512              = -36,
 
        /*  RFC8152: Table 6: EDDSA algs */
 
        LWSCOSE_WKAEDDSA_ALG_EDDSA              = -8,
 
        /*  RFC8152: Table 7: HMAC algs */
 
        LWSCOSE_WKAHMAC_256_64                  = 4,
        LWSCOSE_WKAHMAC_256_256,
        LWSCOSE_WKAHMAC_384_384,
        LWSCOSE_WKAHMAC_512_512,
 
        /*  RFC8152: Table 8: AES algs */
 
        LWSCOSE_WKAAES_128_64                   = 14,
        LWSCOSE_WKAAES_256_64,
        LWSCOSE_WKAAES_128_128                  = 25,
        LWSCOSE_WKAAES_256_128,
 
        /*  RFC8152: Table 9: AES GCM algs */
 
        LWSCOSE_WKAAESGCM_128                   = 1,
        LWSCOSE_WKAAESGCM_192,
        LWSCOSE_WKAAESGCM_256,
 
        /*  RFC8152: Table 10: AES CCM algs */
 
        LWSCOSE_WKAAESCCM_16_64_128             = 10,
        LWSCOSE_WKAAESCCM_16_64_256,
        LWSCOSE_WKAAESCCM_64_64_128,
        LWSCOSE_WKAAESCCM_64_64_256,
        LWSCOSE_WKAAESCCM_16_128_128,
        LWSCOSE_WKAAESCCM_16_128_256,
        LWSCOSE_WKAAESCCM_64_128_128,
        LWSCOSE_WKAAESCCM_64_128_256,
 
        /*  RFC8152: Table 11: CHACHA20 / Poly1305 */
 
        LWSCOSE_WKACHACHA_POLY1305              = 24,
 
        /*  RFC8152: Table 13: HKDF param */
 
        LWSCOSE_WKAPHKDF_SALT                   = -20,
 
        /* RFC8152: Table 14: Context Algorithm Parameters */
 
        LWSCOSE_WKAPCTX_PARTY_U_IDENTITY        = -21,
        LWSCOSE_WKAPCTX_PARTY_U_NONCE           = -22,
        LWSCOSE_WKAPCTX_PARTY_U_OTHER           = -23,
        LWSCOSE_WKAPCTX_PARTY_V_IDENTITY        = -24,
        LWSCOSE_WKAPCTX_PARTY_V_NONCE           = -25,
        LWSCOSE_WKAPCTX_PARTY_V_OTHER           = -26,
 
        /* RFC8152: Table 15: Direct key */
 
        LWSCOSE_WKK_DIRECT_CEK                  = -6,
 
        /* RFC8152: Table 16: Direct key with KDF */
 
        LWSCOSE_WKK_DIRECT_HKDF_SHA_256         = -10,
        LWSCOSE_WKK_DIRECT_HKDF_SHA_512         = -11,
        LWSCOSE_WKK_DIRECT_HKDF_AES_128         = -12,
        LWSCOSE_WKK_DIRECT_HKDF_AES_256         = -13,
 
        /* RFC8152: Table 17: AES Key Wrap Algorithm Values */
 
        LWSCOSE_WKK_DIRECT_HKDFKW_SHA_256       = -3,
        LWSCOSE_WKK_DIRECT_HKDFKW_SHA_512       = -4,
        LWSCOSE_WKK_DIRECT_HKDFKW_AES_128       = -5,
 
        /* RFC8152: Table 18: ECDH Algorithm Values */
 
        LWSCOSE_WKAECDH_ALG_ES_HKDF_256         = -25,
        LWSCOSE_WKAECDH_ALG_ES_HKDF_512         = -26,
        LWSCOSE_WKAECDH_ALG_SS_HKDF_256         = -27,
        LWSCOSE_WKAECDH_ALG_SS_HKDF_512         = -28,
 
        /* RFC8152: Table 19: ECDH Algorithm Parameters */
 
        LWSCOSE_WKAPECDH_EPHEMERAL_KEY          = -1,
        LWSCOSE_WKAPECDH_STATIC_KEY             = -2,
        LWSCOSE_WKAPECDH_STATIC_KEY_ID          = -3,
 
        /* RFC8152: Table 20: ECDH Algorithm Parameters with key wrap */
 
        LWSCOSE_WKAPECDH_ES_A128KW              = -29,
        LWSCOSE_WKAPECDH_ES_A192KW              = -30,
        LWSCOSE_WKAPECDH_ES_A256KW              = -31,
        LWSCOSE_WKAPECDH_SS_A128KW              = -32,
        LWSCOSE_WKAPECDH_SS_A192KW              = -33,
        LWSCOSE_WKAPECDH_SS_A256KW              = -34,
 
        /* RFC8152: Table 21: Key Type Values
         *  https://www.iana.org/assignments/cose/cose.xhtml#key-type
         */
 
        LWSCOSE_WKKTV_OKP                       = 1,
        LWSCOSE_WKKTV_EC2                       = 2,
        LWSCOSE_WKKTV_RSA                       = 3,
        LWSCOSE_WKKTV_SYMMETRIC                 = 4,
        LWSCOSE_WKKTV_HSS_LMS                   = 5,
        LWSCOSE_WKKTV_WALNUTDSA                 = 6,
 
 
        /* RFC8152: Table 22: Elliptic Curves
         * https://www.iana.org/assignments/cose/cose.xhtml#elliptic-curves
         */
 
        LWSCOSE_WKEC_P256                       = 1,
        LWSCOSE_WKEC_P384,
        LWSCOSE_WKEC_P521,
        LWSCOSE_WKEC_X25519,
        LWSCOSE_WKEC_X448,
        LWSCOSE_WKEC_ED25519,
        LWSCOSE_WKEC_ED448,
        LWSCOSE_WKEC_SECP256K1,
 
        /* RFC8152: Table 23: EC Key Parameters */
 
        LWSCOSE_WKECKP_CRV                      = -1,
        LWSCOSE_WKECKP_X                        = -2,
        LWSCOSE_WKECKP_Y                        = -3,
        LWSCOSE_WKECKP_D                        = -4,
 
        /* RFC8152: Table 24: Octet Key Pair (OKP) Parameters */
 
        LWSCOSE_WKOKP_CRV                       = -1,
        LWSCOSE_WKOKP_X                         = -2,
        LWSCOSE_WKOKP_D                         = -4,
 
        /* Additional from
         * https://www.iana.org/assignments/cose/cose.xhtml#key-type-parameters
         */
 
        LWSCOSE_WKKPRSA_N                       = -1,
        LWSCOSE_WKKPRSA_E                       = -2,
        LWSCOSE_WKKPRSA_D                       = -3,
        LWSCOSE_WKKPRSA_P                       = -4,
        LWSCOSE_WKKPRSA_Q                       = -5,
        LWSCOSE_WKKPRSA_DP                      = -6,
        LWSCOSE_WKKPRSA_DQ                      = -7,
        LWSCOSE_WKKPRSA_QINV                    = -8,
        LWSCOSE_WKKPRSA_OTHER                   = -9,
        LWSCOSE_WKKPRSA_RI                      = -10,
        LWSCOSE_WKKPRSA_DI                      = -11,
        LWSCOSE_WKKPRSA_TI                      = -12,
 
        /* RFC8152: Table 25: Symmetric Key Parameters */
 
        LWSCOSE_WKSYMKP_KEY_VALUE               = 4,
 
        /* RFC8152: Table 26: CoAP Content-Formats for COSE */
 
        LWSCOAP_CONTENTFORMAT_COSE_SIGN         = 98,
        LWSCOAP_CONTENTFORMAT_COSE_SIGN1        = 18,
        LWSCOAP_CONTENTFORMAT_COSE_ENCRYPT      = 96,
        LWSCOAP_CONTENTFORMAT_COSE_ENCRYPT0     = 16,
        LWSCOAP_CONTENTFORMAT_COSE_MAC          = 97,
        LWSCOAP_CONTENTFORMAT_COSE_MAC0         = 17,
        LWSCOAP_CONTENTFORMAT_COSE_KEY          = 101,
        LWSCOAP_CONTENTFORMAT_COSE_KEY_SET      = 102,
 
        /* RFC8152: Table 27: Header Parameter for CounterSignature0 */
 
        LWSCOSE_WKL_COUNTERSIGNATURE0           = 9, /* bstr */
 
        /* RFC8812: Table 1: RSASSA-PKCS1-v1_5 Algorithm Values */
 
        LWSCOSE_WKARSA_ALG_RS256                = -257, /* + SHA-256 */
        LWSCOSE_WKARSA_ALG_RS384                = -258, /* + SHA-384 */
        LWSCOSE_WKARSA_ALG_RS512                = -259, /* + SHA-512 */
};
 
enum enum_cose_key_meta_tok {
        COSEKEY_META_KTY,
        COSEKEY_META_KID,
        COSEKEY_META_KEY_OPS,
        COSEKEY_META_BASE_IV,
        COSEKEY_META_ALG,
 
        LWS_COUNT_COSE_KEY_ELEMENTS
};
 
typedef int64_t cose_param_t;
 
LWS_VISIBLE LWS_EXTERN const char *
lws_cose_alg_to_name(cose_param_t alg);
 
LWS_VISIBLE LWS_EXTERN cose_param_t
lws_cose_name_to_alg(const char *name);
 
/*
 * cose_key
 */
 
typedef struct lws_cose_key {
        /* key data elements */
        struct lws_gencrypto_keyelem    e[LWS_GENCRYPTO_MAX_KEYEL_COUNT];
        /* generic meta key elements, like KID */
        struct lws_gencrypto_keyelem    meta[LWS_COUNT_COSE_KEY_ELEMENTS];
        lws_dll2_t                      list; /* used when part of a set */
        int                             gencrypto_kty;  /**< one of LWS_GENCRYPTO_KTY_ */
        cose_param_t                    kty;
        cose_param_t                    cose_alg;
        cose_param_t                    cose_curve;
        char                            private_key; /* nonzero = has private key elements */
} lws_cose_key_t;
 
typedef int (*lws_cose_key_import_callback)(struct lws_cose_key *s, void *user);
 
/** lws_cose_jwk_import() - Create an lws_cose_key_t object from cose_key CBOR
 *
 * \param pkey_set: NULL, or a pointer to an lws_dll2_owner_t for a cose_key set
 * \param cb: callback for each jwk-processed key, or NULL if importing a single
 *            key with no parent "keys" JSON
 * \param user: pointer to be passed to the callback, otherwise ignored by lws.
 *              NULL if importing a single key with no parent "keys" JSON
 * \param in: a single cose_key
 * \param len: the length of the cose_key in bytes
 *
 * Creates a single lws_cose_key_t if \p pkey_set is NULL or if the incoming
 * CBOR doesn't start with an array, otherwise expects a CBOR array containing
 * zero or more cose_key CBOR, and adds each to the \p pkey_set
 * lws_dll2_owner_t struct.  Created lws_cose_key_t are filled with data from
 * the COSE representation and can be used with other COSE crypto ops.
 */
LWS_VISIBLE LWS_EXTERN lws_cose_key_t *
lws_cose_key_import(lws_dll2_owner_t *pkey_set, lws_cose_key_import_callback cb,
                    void *user, const uint8_t *in, size_t len);
 
/** lws_cose_key_export() - Create cose_key CBOR from an lws_cose_key_t
 *
 * \param ck: the lws_cose_key_t to export to CBOR
 * \param ctx: the CBOR writing context (same as for lws_lec_printf())
 * \param flags: 0 to export only public elements, or LWSJWKF_EXPORT_PRIVATE
 *
 * Creates an lws_jwk struct filled with data from the COSE representation.
 */
LWS_VISIBLE LWS_EXTERN enum lws_lec_pctx_ret
lws_cose_key_export(lws_cose_key_t *ck, lws_lec_pctx_t *ctx, int flags);
 
/**
 * lws_cose_key_generate() - generate a fresh key
 *
 * \param context: the lws_context used to get random
 * \param cose_kty: one of LWSCOSE_WKKTV_ indicating the well-known key type
 * \param use_mask: 0, or a bitfield where (1 << LWSCOSE_WKKO_...) set means valid for use
 * \param bits: key bits for RSA
 * \param curve: for EC keys, one of "P-256", "P-384" or "P-521" currently
 * \param kid: string describing the key, or NULL
 *
 * Create an lws_cose_key_t of the specified type and return it
 */
LWS_VISIBLE LWS_EXTERN lws_cose_key_t *
lws_cose_key_generate(struct lws_context *context, cose_param_t cose_kty,
                      int use_mask, int bits, const char *curve,
                      const uint8_t *kid, size_t kl);
 
LWS_VISIBLE LWS_EXTERN lws_cose_key_t *
lws_cose_key_from_set(lws_dll2_owner_t *set, const uint8_t *kid, size_t kl);
 
LWS_VISIBLE LWS_EXTERN void
lws_cose_key_destroy(lws_cose_key_t **ck);
 
LWS_VISIBLE LWS_EXTERN void
lws_cose_key_set_destroy(lws_dll2_owner_t *o);
 
/* only available in _DEBUG build */
 
LWS_VISIBLE LWS_EXTERN void
lws_cose_key_dump(const lws_cose_key_t *ck);
 
/*
 * cose_sign
 */
 
struct lws_cose_validate_context;
 
 
enum lws_cose_sig_types {
        SIGTYPE_UNKNOWN,
        SIGTYPE_MULTI,
        SIGTYPE_SINGLE,
        SIGTYPE_COUNTERSIGNED, /* not yet supported */
        SIGTYPE_MAC, /* only supported for validation */
        SIGTYPE_MAC0,
};
 
/* a list of these result objects is the output of the validation process */
 
typedef struct {
        lws_dll2_t              list;
 
        const lws_cose_key_t    *cose_key;
        cose_param_t            cose_alg;
 
        int                     result; /* 0 = validated */
 
} lws_cose_validate_res_t;
 
enum {
        LCOSESIGEXTCB_RET_FINISHED,
        LCOSESIGEXTCB_RET_AGAIN,
        LCOSESIGEXTCB_RET_ERROR         = -1
};
 
typedef struct {
        struct lws_cose_validate_context *cps;
        const uint8_t                    *ext;
        size_t                           xl;
} lws_cose_sig_ext_pay_t;
 
typedef int (*lws_cose_sign_ext_pay_cb_t)(lws_cose_sig_ext_pay_t *x);
typedef int (*lws_cose_validate_pay_cb_t)(struct lws_cose_validate_context *cps,
                                          void *opaque, const uint8_t *paychunk,
                                          size_t paychunk_len);
 
typedef struct lws_cose_validate_create_info {
        struct lws_context              *cx;
        /**< REQUIRED: the lws context */
        lws_dll2_owner_t                *keyset;
        /**< REQUIRED: one or more cose_keys */
 
        enum lws_cose_sig_types         sigtype;
        /**<  0 if a CBOR tag is in the sig, else one of SIGTYPE_MULTI,
         * SIGTYPE_SINGLE, etc*/
 
        lws_cose_validate_pay_cb_t      pay_cb;
        /**< optional: called back with unvalidated payload pieces */
        void                            *pay_opaque;
        /**< optional: passed into pay_cb callback along with payload chunk */
 
        lws_cose_sign_ext_pay_cb_t      ext_cb;
        /**< optional extra application data provision callback */
        void                            *ext_opaque;
        /**< optional extra application data provision callback opaque */
        size_t                          ext_len;
        /**< if we have extra app data, this must be set to the length of it */
} lws_cose_validate_create_info_t;
 
/**
 * lws_cose_validate_create() - create a signature validation context
 *
 * \param info: struct describing the validation context to create
 *
 * Creates a signature validation context set up as described in \p info.
 *
 * You can then pass the signature cbor chunks to it using
 * lws_cose_validate_chunk(), finialize and get the results list using
 * lws_cose_validate_results() and destroy with lws_cose_validate_destroy().
 */
LWS_VISIBLE LWS_EXTERN struct lws_cose_validate_context *
lws_cose_validate_create(const lws_cose_validate_create_info_t *info);
 
/**
 * lws_cose_validate_chunk() - passes chunks of CBOR into the signature validator
 *
 * \param cps: the validation context
 * \param in: the chunk of CBOR (does not have to be logically complete)
 * \param in_len: number of bytes available at \p in
 *
 * Parses signature CBOR to produce a list of result objects.
 *
 *
 */
LWS_VISIBLE LWS_EXTERN int
lws_cose_validate_chunk(struct lws_cose_validate_context *cps,
                        const uint8_t *in, size_t in_len, size_t *used_in);
 
LWS_VISIBLE LWS_EXTERN lws_dll2_owner_t *
lws_cose_validate_results(struct lws_cose_validate_context *cps);
 
LWS_VISIBLE LWS_EXTERN void
lws_cose_validate_destroy(struct lws_cose_validate_context **cps);
 
struct lws_cose_sign_context;
 
#define LCSC_FL_ADD_CBOR_TAG            (1 << 0)
#define LCSC_FL_ADD_CBOR_PREFER_MAC0    (1 << 1)
 
typedef struct lws_cose_sign_create_info {
        struct lws_context              *cx;
        /**< REQUIRED: the lws context */
        lws_dll2_owner_t                *keyset;
        /**< REQUIRED: one or more cose_keys */
 
        lws_lec_pctx_t                  *lec;
        /**< REQUIRED: the cbor output context to emit to, user must
         * initialize with lws_lec_init() beforehand */
 
        lws_cose_sign_ext_pay_cb_t      ext_cb;
        /**< optional extra application data provision callback */
        void                            *ext_opaque;
        /**< optional extra application data provision callback opaque */
        size_t                          ext_len;
        /**< if we have extra app data, this must be set to the length of it */
 
        size_t                          inline_payload_len;
        /**< REQUIRED: size of the inline payload we will provide */
 
        int                             flags;
        /**< bitmap of  LCSC_FL_* */
        enum lws_cose_sig_types         sigtype;
        /**< 0, or sign type hint */
} lws_cose_sign_create_info_t;
 
/**
 * lws_cose_sign_create() - Create a signing context
 *
 * \param info: a structure describing the signing context you want to create
 *
 * This allocates and returns a signing context created according to what is in
 * the \p info parameter.
 *
 * \p info must be prepared with the lws_context, a keyset to use, a CBOR
 * output context, and the inline payload length.
 *
 * Returns NULL on failure or the created signing context ready to add alg(s)
 * to.
 */
 
LWS_VISIBLE LWS_EXTERN struct lws_cose_sign_context *
lws_cose_sign_create(const lws_cose_sign_create_info_t *info);
 
LWS_VISIBLE LWS_EXTERN int
lws_cose_sign_add(struct lws_cose_sign_context *csc, cose_param_t alg,
                  const lws_cose_key_t *ck);
 
LWS_VISIBLE LWS_EXTERN enum lws_lec_pctx_ret
lws_cose_sign_payload_chunk(struct lws_cose_sign_context *csc,
                            const uint8_t *in, size_t in_len);
 
LWS_VISIBLE LWS_EXTERN void
lws_cose_sign_destroy(struct lws_cose_sign_context **csc);
 
//@}