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agent:kem:ecc: Support a key on smartcard.
* agent/agent.h (agent_card_ecc_kem): New. * agent/divert-scd.c (agent_card_ecc_kem): New. * agent/pkdecrypt.c (ecc_extract_pk_from_key): New. (ecc_extract_sk_from_key): New. (ecc_raw_kem, get_cardkey, ecc_get_curve): New. (ecc_pgp_kem_decrypt): Support a key on smartcard for ECC. (composite_pgp_kem_decrypt): Handle a case of a key on smartcard. * common/sexputil.c (get_ecc_curve_from_key): New. * common/util.h (get_ecc_curve_from_key): New. -- GnuPG-bug-id: 7097 Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka
parent
83e2dede0a
commit
9128d81bb7
@ -705,6 +705,9 @@ gpg_error_t divert_writekey (ctrl_t ctrl, int force, const char *serialno,
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const char *keyref,
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const char *keydata, size_t keydatalen);
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gpg_error_t agent_card_ecc_kem (ctrl_t ctrl, const unsigned char *ecc_ct,
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size_t ecc_point_len, unsigned char *ecc_ecdh);
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/*-- call-daemon.c --*/
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gpg_error_t daemon_start (enum daemon_type type, ctrl_t ctrl);
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assuan_context_t daemon_type_ctx (enum daemon_type type, ctrl_t ctrl);
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@ -753,6 +756,7 @@ int agent_card_pkdecrypt (ctrl_t ctrl,
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const char *desc_text,
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const unsigned char *indata, size_t indatalen,
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char **r_buf, size_t *r_buflen, int *r_padding);
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int agent_card_readcert (ctrl_t ctrl,
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const char *id, char **r_buf, size_t *r_buflen);
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int agent_card_readkey (ctrl_t ctrl, const char *id,
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@ -774,7 +778,6 @@ void agent_card_free_keyinfo (struct card_key_info_s *l);
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gpg_error_t agent_card_keyinfo (ctrl_t ctrl, const char *keygrip,
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int cap, struct card_key_info_s **result);
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/*-- learncard.c --*/
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int agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context, int force);
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@ -486,6 +486,34 @@ divert_pkdecrypt (ctrl_t ctrl,
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return rc;
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}
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gpg_error_t
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agent_card_ecc_kem (ctrl_t ctrl, const unsigned char *ecc_ct,
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size_t ecc_point_len, unsigned char *ecc_ecdh)
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{
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gpg_error_t err = 0;
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char *ecdh = NULL;
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size_t len;
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int rc;
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rc = agent_card_pkdecrypt (ctrl, ctrl->keygrip, getpin_cb, ctrl, NULL,
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ecc_ct, ecc_point_len, &ecdh, &len, NULL);
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if (rc)
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return rc;
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if (len != ecc_point_len)
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{
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if (opt.verbose)
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log_info ("%s: ECC result length invalid (%zu != %zu)\n",
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__func__, len, ecc_point_len);
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return gpg_error (GPG_ERR_INV_DATA);
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}
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else
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memcpy (ecc_ecdh, ecdh, len);
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xfree (ecdh);
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return err;
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}
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gpg_error_t
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divert_writekey (ctrl_t ctrl, int force, const char *serialno,
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@ -40,7 +40,7 @@ struct ecc_params
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size_t point_len;
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size_t shared_len;
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int hash_algo;
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int algo;
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int kem_algo;
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int scalar_reverse;
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};
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@ -245,65 +245,21 @@ reverse_buffer (unsigned char *buffer, unsigned int length)
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static gpg_error_t
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ecc_pgp_kem_decrypt (ctrl_t ctrl, gcry_sexp_t s_skey0,
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const unsigned char *ecc_ct, size_t ecc_ct_len,
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unsigned char *ecc_ss, size_t *r_shared_len, size_t *r_point_len)
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ecc_extract_pk_from_key (const struct ecc_params *ecc, gcry_sexp_t s_skey,
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unsigned char *ecc_pk)
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{
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gpg_error_t err = 0;
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const struct ecc_params *ecc;
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gpg_error_t err;
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unsigned int nbits;
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const unsigned char *p;
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size_t len;
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gcry_mpi_t ecc_sk_mpi = NULL;
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unsigned char ecc_sk[ECC_SCALAR_LEN_MAX];
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gcry_mpi_t ecc_pk_mpi = NULL;
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unsigned char ecc_pk[ECC_POINT_LEN_MAX];
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unsigned char ecc_ecdh[ECC_POINT_LEN_MAX];
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gcry_sexp_t curve = NULL;
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char *curve_name = NULL;
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(void)ctrl;
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curve = gcry_sexp_find_token (s_skey0, "curve", 0);
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if (!curve)
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{
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if (opt.verbose)
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log_info ("%s: no curve given\n", __func__);
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return gpg_error (GPG_ERR_BAD_SECKEY);
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}
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curve_name = gcry_sexp_nth_string (curve, 1);
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ecc = get_ecc_params (curve_name);
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if (!ecc)
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{
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if (opt.verbose)
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log_info ("%s: curve '%s' not supported\n", __func__, curve_name);
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err = gpg_error (GPG_ERR_BAD_SECKEY);
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goto leave;
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}
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*r_shared_len = ecc->shared_len;
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*r_point_len = ecc->point_len;
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if (ecc->point_len != ecc_ct_len)
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{
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if (opt.verbose)
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log_info ("%s: ECC cipher text length invalid (%zu)\n",
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__func__, ecc->point_len);
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err = gpg_error (GPG_ERR_INV_DATA);
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goto leave;
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}
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err = gcry_sexp_extract_param (s_skey0, NULL, "/qd",
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&ecc_pk_mpi, &ecc_sk_mpi, NULL);
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err = gcry_sexp_extract_param (s_skey, NULL, "/q", &ecc_pk_mpi, NULL);
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if (err)
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{
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if (opt.verbose)
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log_info ("%s: extracting q and d from ECC key failed\n", __func__);
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goto leave;
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return err;
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}
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p = gcry_mpi_get_opaque (ecc_pk_mpi, &nbits);
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@ -326,8 +282,31 @@ ecc_pgp_kem_decrypt (ctrl_t ctrl, gcry_sexp_t s_skey0,
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goto leave;
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}
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if (DBG_CRYPTO)
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log_printhex (ecc_pk, ecc->pubkey_len, "ECC pubkey:");
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leave:
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mpi_release (ecc_pk_mpi);
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ecc_pk_mpi = NULL;
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return err;
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}
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static gpg_error_t
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ecc_extract_sk_from_key (const struct ecc_params *ecc, gcry_sexp_t s_skey,
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unsigned char *ecc_sk)
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{
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gpg_error_t err;
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unsigned int nbits;
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const unsigned char *p;
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size_t len;
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gcry_mpi_t ecc_sk_mpi = NULL;
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err = gcry_sexp_extract_param (s_skey, NULL, "/d", &ecc_sk_mpi, NULL);
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if (err)
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{
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if (opt.verbose)
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log_info ("%s: extracting d from ECC key failed\n", __func__);
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return err;
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}
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p = gcry_mpi_get_opaque (ecc_sk_mpi, &nbits);
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len = (nbits+7)/8;
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@ -346,47 +325,206 @@ ecc_pgp_kem_decrypt (ctrl_t ctrl, gcry_sexp_t s_skey0,
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ecc_sk_mpi = NULL;
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if (DBG_CRYPTO)
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log_printhex (ecc_sk, ecc->scalar_len, "ECC seckey:");
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leave:
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mpi_release (ecc_sk_mpi);
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return err;
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}
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static gpg_error_t
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ecc_raw_kem (const struct ecc_params *ecc, gcry_sexp_t s_skey,
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const unsigned char *ecc_ct, unsigned char *ecc_ecdh)
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{
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gpg_error_t err = 0;
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unsigned char ecc_sk[ECC_SCALAR_LEN_MAX];
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if (ecc->scalar_len > ECC_SCALAR_LEN_MAX)
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{
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log_debug ("ECC curve: %s\n", curve_name);
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log_printhex (ecc_pk, ecc->pubkey_len, "ECC pubkey:");
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log_printhex (ecc_sk, ecc->scalar_len, "ECC seckey:");
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log_printhex (ecc_ct, ecc->point_len, "ECC ephem:");
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if (opt.verbose)
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log_info ("%s: ECC scalar length invalid (%zu)\n",
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__func__, ecc->scalar_len);
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err = gpg_error (GPG_ERR_INV_DATA);
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goto leave;
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}
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err = gcry_kem_decap (ecc->algo, ecc_sk, ecc->scalar_len,
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ecc_ct, ecc->point_len, ecc_ecdh, ecc->point_len, NULL, 0);
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err = ecc_extract_sk_from_key (ecc, s_skey, ecc_sk);
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if (err)
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goto leave;
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err = gcry_kem_decap (ecc->kem_algo, ecc_sk, ecc->scalar_len,
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ecc_ct, ecc->point_len, ecc_ecdh, ecc->point_len,
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NULL, 0);
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if (err)
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{
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if (opt.verbose)
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log_info ("%s: gcry_kem_decap for ECC failed\n", __func__);
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}
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leave:
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wipememory (ecc_sk, sizeof ecc_sk);
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return err;
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}
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static gpg_error_t
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get_cardkey (ctrl_t ctrl, const char *keygrip, gcry_sexp_t *r_s_pk)
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{
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gpg_error_t err;
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unsigned char *pkbuf;
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size_t pkbuflen;
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err = agent_card_readkey (ctrl, keygrip, &pkbuf, NULL);
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if (err)
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return err;
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pkbuflen = gcry_sexp_canon_len (pkbuf, 0, NULL, NULL);
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err = gcry_sexp_sscan (r_s_pk, NULL, (char*)pkbuf, pkbuflen);
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if (err)
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log_error ("failed to build S-Exp from received card key: %s\n",
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gpg_strerror (err));
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xfree (pkbuf);
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return err;
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}
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static gpg_error_t
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ecc_get_curve (ctrl_t ctrl, gcry_sexp_t s_skey, const char **r_curve)
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{
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gpg_error_t err = 0;
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gcry_sexp_t s_skey_card = NULL;
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const char *curve = NULL;
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gcry_sexp_t key;
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*r_curve = NULL;
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if (!s_skey)
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{
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err = get_cardkey (ctrl, ctrl->keygrip, &s_skey_card);
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if (err)
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goto leave;
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key = s_skey_card;
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}
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else
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key = s_skey;
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curve = get_ecc_curve_from_key (key);
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if (!curve)
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{
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err = gpg_error (GPG_ERR_BAD_SECKEY);
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goto leave;
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}
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*r_curve = curve;
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leave:
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gcry_sexp_release (s_skey_card);
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return err;
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}
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/* Given a private key in SEXP by S_SKEY0 and a cipher text by ECC_CT
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* with length ECC_POINT_LEN, do ECC-KEM operation. Result is
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* returned in the memory referred by ECC_SS. Shared secret length is
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* returned in the memory referred by R_SHARED_LEN. CTRL is used to
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* access smartcard, internally. */
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static gpg_error_t
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ecc_pgp_kem_decrypt (ctrl_t ctrl, gcry_sexp_t s_skey0,
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unsigned char *shadow_info0,
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const unsigned char *ecc_ct, size_t ecc_point_len,
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unsigned char *ecc_ss, size_t *r_shared_len)
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{
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gpg_error_t err;
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unsigned char ecc_ecdh[ECC_POINT_LEN_MAX];
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unsigned char ecc_pk[ECC_POINT_LEN_MAX];
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const char *curve;
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const struct ecc_params *ecc = NULL;
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if (ecc_point_len > ECC_POINT_LEN_MAX)
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return gpg_error (GPG_ERR_INV_DATA);
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err = ecc_get_curve (ctrl, s_skey0, &curve);
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if (err)
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{
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if ((gpg_err_code (err) == GPG_ERR_CARD_REMOVED
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|| gpg_err_code (err) == GPG_ERR_CARD_NOT_PRESENT)
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&& !s_skey0)
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err = gpg_error (GPG_ERR_NO_SECKEY);
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return err;
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}
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ecc = get_ecc_params (curve);
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if (!ecc)
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{
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if (opt.verbose)
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log_info ("%s: curve '%s' not supported\n", __func__, curve);
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return gpg_error (GPG_ERR_BAD_SECKEY);
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}
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*r_shared_len = ecc->shared_len;
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if (DBG_CRYPTO)
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log_printhex (ecc_ecdh, ecc->point_len, "ECC ecdh:");
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log_debug ("ECC curve: %s\n", curve);
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if (ecc->point_len != ecc_point_len)
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{
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if (opt.verbose)
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log_info ("%s: ECC cipher text length invalid (%zu != %zu)\n",
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__func__, ecc->point_len, ecc_point_len);
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return gpg_error (GPG_ERR_INV_DATA);
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}
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err = ecc_extract_pk_from_key (ecc, s_skey0, ecc_pk);
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if (err)
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return err;
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if (DBG_CRYPTO)
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log_printhex (ecc_ct, ecc->point_len, "ECC ephem:");
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if (shadow_info0 || !s_skey0)
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{
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if (s_skey0 && agent_is_tpm2_key (s_skey0))
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{
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log_error ("TPM decryption failed: %s\n", gpg_strerror (err));
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return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
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}
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else
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{
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err = agent_card_ecc_kem (ctrl, ecc_ct, ecc->point_len, ecc_ecdh);
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if (err)
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{
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log_error ("smartcard decryption failed: %s\n",
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gpg_strerror (err));
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return err;
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}
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}
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}
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else
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err = ecc_raw_kem (ecc, s_skey0, ecc_ct, ecc_ecdh);
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if (err)
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return err;
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if (DBG_CRYPTO)
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log_printhex (ecc_ecdh, ecc_point_len, "ECC ecdh:");
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err = gnupg_ecc_kem_kdf (ecc_ss, ecc->shared_len, ecc->hash_algo,
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ecc_ecdh, ecc->point_len, ecc_ct, ecc->point_len,
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ecc_pk, ecc->point_len);
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wipememory (ecc_ecdh, sizeof ecc_ecdh);
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if (err)
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{
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if (opt.verbose)
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log_info ("%s: kdf for ECC failed\n", __func__);
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goto leave;
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return err;
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}
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if (DBG_CRYPTO)
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log_printhex (ecc_ss, ecc->shared_len, "ECC shared:");
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leave:
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wipememory (ecc_sk, sizeof ecc_sk);
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wipememory (ecc_ecdh, sizeof ecc_ecdh);
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mpi_release (ecc_pk_mpi);
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mpi_release (ecc_sk_mpi);
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xfree (curve_name);
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gcry_sexp_release (curve);
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return err;
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return 0;
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}
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/* For composite PGP KEM (ECC+ML-KEM), decrypt CIPHERTEXT using KEM API.
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@ -447,7 +585,7 @@ composite_pgp_kem_decrypt (ctrl_t ctrl, const char *desc_text,
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err = agent_key_from_file (ctrl, NULL, desc_text,
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ctrl->keygrip, &shadow_info0,
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CACHE_MODE_NORMAL, NULL, &s_skey0, NULL, NULL);
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if (err)
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if (err && gpg_err_code (err) != GPG_ERR_NO_SECKEY)
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{
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log_error ("failed to read the secret key\n");
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goto leave;
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@ -456,14 +594,13 @@ composite_pgp_kem_decrypt (ctrl_t ctrl, const char *desc_text,
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err = agent_key_from_file (ctrl, NULL, desc_text,
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ctrl->keygrip1, &shadow_info1,
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CACHE_MODE_NORMAL, NULL, &s_skey1, NULL, NULL);
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/* Here assumes no smartcard for ML-KEM, but private key in a file. */
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if (err)
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{
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log_error ("failed to read the another secret key\n");
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goto leave;
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}
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/* Here assumes no smartcard, but private keys */
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err = gcry_sexp_extract_param (s_cipher, NULL, "%dc/eks&'fixed-info'",
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&algo, &ecc_ct_mpi, &mlkem_ct_mpi,
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&encrypted_sessionkey_mpi, &fixed_info, NULL);
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@ -491,8 +628,9 @@ composite_pgp_kem_decrypt (ctrl_t ctrl, const char *desc_text,
|
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}
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/* Firstly, ECC part. */
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err = ecc_pgp_kem_decrypt (ctrl, s_skey0, ecc_ct, ecc_ct_len,
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ecc_ss, &ecc_shared_len, &ecc_point_len);
|
||||
ecc_point_len = ecc_ct_len;
|
||||
err = ecc_pgp_kem_decrypt (ctrl, s_skey0, shadow_info0, ecc_ct, ecc_point_len,
|
||||
ecc_ss, &ecc_shared_len);
|
||||
if (err)
|
||||
goto leave;
|
||||
|
||||
|
||||
@ -1194,3 +1194,47 @@ cipher_mode_to_string (int mode)
|
||||
default: return "[?]";
|
||||
}
|
||||
}
|
||||
|
||||
/* Return the cannonical name of the ECC curve in KEY. */
|
||||
const char *
|
||||
get_ecc_curve_from_key (gcry_sexp_t key)
|
||||
{
|
||||
gcry_sexp_t list = NULL;
|
||||
gcry_sexp_t l2 = NULL;
|
||||
const char *curve_name = NULL;
|
||||
char *name = NULL;
|
||||
|
||||
/* Check that the first element is valid. */
|
||||
list = gcry_sexp_find_token (key, "public-key", 0);
|
||||
if (!list)
|
||||
list = gcry_sexp_find_token (key, "private-key", 0);
|
||||
if (!list)
|
||||
list = gcry_sexp_find_token (key, "protected-private-key", 0);
|
||||
if (!list)
|
||||
list = gcry_sexp_find_token (key, "shadowed-private-key", 0);
|
||||
if (!list)
|
||||
goto leave;
|
||||
|
||||
l2 = gcry_sexp_cadr (list);
|
||||
gcry_sexp_release (list);
|
||||
list = l2;
|
||||
l2 = NULL;
|
||||
|
||||
name = gcry_sexp_nth_string (list, 0);
|
||||
if (!name)
|
||||
goto leave;
|
||||
|
||||
if (gcry_pk_map_name (name) != GCRY_PK_ECC)
|
||||
goto leave;
|
||||
|
||||
l2 = gcry_sexp_find_token (list, "curve", 0);
|
||||
xfree (name);
|
||||
name = gcry_sexp_nth_string (l2, 1);
|
||||
curve_name = openpgp_oid_or_name_to_curve (name, 1);
|
||||
gcry_sexp_release (l2);
|
||||
|
||||
leave:
|
||||
xfree (name);
|
||||
gcry_sexp_release (list);
|
||||
return curve_name;
|
||||
}
|
||||
|
||||
@ -196,6 +196,7 @@ char *pubkey_algo_string (gcry_sexp_t s_pkey, enum gcry_pk_algos *r_algoid);
|
||||
const char *pubkey_algo_to_string (int algo);
|
||||
const char *hash_algo_to_string (int algo);
|
||||
const char *cipher_mode_to_string (int mode);
|
||||
const char *get_ecc_curve_from_key (gcry_sexp_t key);
|
||||
|
||||
/*-- convert.c --*/
|
||||
int hex2bin (const char *string, void *buffer, size_t length);
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user