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/*
webid-oidc, implementation of the Solid specification
Copyright (C) 2020, 2021 Vivien Kraus
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <utilities.h>
#define _(s) dgettext (PACKAGE, s)
void webid_oidc_random (size_t len, uint8_t * dst);
SCM webidoidc_hash_g (SCM alg, SCM payload);
/* Register "generate-key", a guile function to generate a keypair. */
void init_webidoidc_jwk (void);
SCM_KEYWORD (kw_crv, "crv");
SCM_KEYWORD (kw_e, "e");
SCM_KEYWORD (kw_n_size, "n-size");
SCM_KEYWORD (kw_e_size, "e-size");
SCM_SYMBOL (kty_ec, "EC");
SCM_SYMBOL (kty_rsa, "RSA");
SCM_SYMBOL (unsupported_kty, "unsupported-kty");
SCM_SYMBOL (unsupported_crv, "unsupported-crv");
SCM_SYMBOL (invalid_parameters, "invalid-parameters");
SCM_SYMBOL (base64_decoding_error, "base64-decoding-error");
/* Required for utilities.h */
SCM_SYMBOL (p256, "P-256");
SCM_SYMBOL (p384, "P-384");
SCM_SYMBOL (p521, "P-521");
SCM_SYMBOL (kcrv, "crv");
SCM_SYMBOL (kx, "x");
SCM_SYMBOL (ky, "y");
SCM_SYMBOL (kd, "d");
SCM_SYMBOL (kn, "n");
SCM_SYMBOL (ke, "e");
SCM_SYMBOL (kp, "p");
SCM_SYMBOL (kq, "q");
SCM_SYMBOL (kdp, "dp");
SCM_SYMBOL (kdq, "dq");
SCM_SYMBOL (kqi, "qi");
SCM_SYMBOL (kkty, "kty");
static void
generate_random (void *unused, size_t len, uint8_t * dst)
{
(void) unused;
webid_oidc_random (len, dst);
}
SCM_DEFINE (webidoidc_generate_key_g, "generate-key", 0, 0, 1, (SCM rest),
"Generate a key pair. The parameters are passed as keyword arguments: @code{#:crv}, @code{#:n-size}, @code{#:e} or @code{#:e-size}. Return an alist of the parameters. If @code{#:crv} is specified, generate an EC key pair using the curve, @code{'P-256}, @code{'P-384} or @code{'P-521}. If @code{#:n-size} is specified, generate an RSA key pair that many bits long. Otherwise, this is an error. If @code{#:e} is set, use that for the exponent instead of AQAB. If @code{#:e-size} is set, generate the exponent that many bits long.")
{
SCM crv = SCM_UNDEFINED;
SCM n_size = SCM_UNDEFINED;
SCM e_size = scm_from_int (0);
SCM e = scm_from_utf8_string ("AQAB");
const struct ecc_curve *c_crv = NULL;
SCM ret = SCM_EOL;
scm_c_bind_keyword_arguments ("generate-key", rest, 0,
kw_crv, &crv,
kw_n_size, &n_size,
kw_e_size, &e_size, kw_e, &e, SCM_UNDEFINED);
if (!SCM_UNBNDP (crv))
{
c_crv = do_ecc_curve_load (crv, 1);
}
else if (!SCM_UNBNDP (n_size))
{
/* This is a RSA key pair */
}
else
{
scm_throw (unsupported_kty, SCM_EOL);
}
if (c_crv)
{
struct ecc_point c_point;
struct ecc_scalar c_scalar;
scm_dynwind_begin (0);
ecc_point_init (&c_point, c_crv);
dynwind_ecc_point_clear (&c_point);
ecc_scalar_init (&c_scalar, c_crv);
dynwind_ecc_scalar_clear (&c_scalar);
ecdsa_generate_keypair (&c_point, &c_scalar, NULL, generate_random);
ret = wrap_ecc_key_pair (c_crv, &c_point, &c_scalar);
scm_dynwind_end ();
}
else
{
struct rsa_public_key c_pub;
struct rsa_private_key c_key;
scm_dynwind_begin (0);
rsa_public_key_init (&c_pub);
dynwind_rsa_public_key_clear (&c_pub);
rsa_private_key_init (&c_key);
dynwind_rsa_private_key_clear (&c_key);
do_mpz_t_load (c_pub.e, e, 1);
if (rsa_generate_keypair (&c_pub, &c_key,
NULL, &generate_random,
NULL, NULL,
scm_to_uint (n_size), scm_to_uint (e_size)))
{
ret = wrap_rsa_key_pair (&c_pub, &c_key);;
}
else
{
scm_throw (invalid_parameters, scm_list_3 (n_size, e_size, e));
}
scm_dynwind_end ();
}
return ret;
}
SCM_DEFINE (webidoidc_kty_g, "kty", 1, 0, 0, (SCM key),
"Return the type of @var{key}, @code{'EC} or @code{'RSA}. Return @code{#f} if this is not a JWK.")
{
SCM crv = scm_assq_ref (key, kcrv);
const struct ecc_curve *c_crv = NULL;
struct ecc_point c_point;
struct ecc_scalar c_scalar;
struct rsa_public_key c_pub;
struct rsa_private_key c_key;
SCM ret = SCM_BOOL_F;
if (scm_is_true (crv))
{
c_crv = do_ecc_curve_load (crv, 0);
}
scm_dynwind_begin (0);
if (c_crv)
{
ecc_point_init (&c_point, c_crv);
dynwind_ecc_point_clear (&c_point);
ecc_scalar_init (&c_scalar, c_crv);
dynwind_ecc_scalar_clear (&c_scalar);
}
rsa_public_key_init (&c_pub);
dynwind_rsa_public_key_clear (&c_pub);
rsa_private_key_init (&c_key);
dynwind_rsa_private_key_clear (&c_key);
if (c_crv
&& (do_ecc_point_load (&c_point, key)
|| do_ecc_scalar_load (&c_scalar, key)))
{
ret = kty_ec;
}
else if (do_rsa_public_key_load (&c_pub, key)
|| do_rsa_private_key_load (&c_key, key))
{
ret = kty_rsa;
}
scm_dynwind_end ();
return ret;
}
SCM_DEFINE (webidoidc_strip_key_g, "strip-key", 1, 0, 0, (SCM key),
"Strip a JWK, keeping only the parts that are required for a public key. The fields are sorted aphabetically.")
{
SCM kty = webidoidc_kty_g (key);
SCM crv = scm_assq_ref (key, kcrv);
SCM x = scm_assq_ref (key, kx);
SCM y = scm_assq_ref (key, ky);
SCM n = scm_assq_ref (key, kn);
SCM e = scm_assq_ref (key, ke);
if (scm_is_eq (kty, kty_ec))
{
return scm_list_4 (scm_cons (kcrv, crv),
scm_cons (kkty, kty_ec),
scm_cons (kx, x), scm_cons (ky, y));
}
if (scm_is_eq (kty, kty_rsa))
{
return scm_list_3 (scm_cons (ke, e),
scm_cons (kkty, kty_rsa), scm_cons (kn, n));
}
scm_throw (unsupported_kty, scm_list_1 (key));
}
static SCM scm_to_json_string;
SCM_SYMBOL (sha256, "SHA-256");
SCM_DEFINE (webidoidc_jkt_g, "jkt", 1, 0, 0, (SCM key), "Hash a public key.")
{
SCM stripped = webidoidc_strip_key_g (key);
SCM as_json = scm_call_1 (scm_to_json_string, stripped);
SCM as_bytevector = scm_string_to_utf8 (as_json);
return webidoidc_hash_g (sha256, as_bytevector);
}
void
init_webidoidc_jwk (void)
{
scm_to_json_string = scm_c_public_ref ("json", "scm->json-string");
#ifndef SCM_MAGIC_SNARFER
#include "libwebidoidc-jwk.x"
#endif /* not SCM_MAGIC_SNARFER */
}
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