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gpg: Support encryption with kyber_cv448. 

* g10/pkglue.c (do_encrypt_kem): Support cv25519 w/o 0x40
prefix. Support X448.
(ECC_POINT_LEN_MAX): New.
(ECC_HASH_LEN_MAX): New.
* common/openpgp-oid.c (oidtable): Support X448 KEM.
--

This needs more work.  For example we should use a parameter table
like what we do in agent/pkdecrypt.c.

GnuPG-bug-id: 6815
This commit is contained in:
Werner Koch 2024-04-23 11:20:37 +02:00
parent f305e703d5
commit e591fd25ad
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
2 changed files with 41 additions and 14 deletions
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2
common/openpgp-oid.c
View File

@ -57,7 +57,7 @@ static struct {
{ "Ed25519", "1.3.101.112", 255, "ed25519", NULL,
PUBKEY_ALGO_EDDSA },
{ "X448", "1.3.101.111", 448, "cv448", NULL,
PUBKEY_ALGO_ECDH },
PUBKEY_ALGO_ECDH, GCRY_KEM_RAW_X448 },
{ "Ed448", "1.3.101.113", 456, "ed448", NULL,
PUBKEY_ALGO_EDDSA },

53
g10/pkglue.c
View File

@ -32,6 +32,12 @@
#include "main.h"
#include "options.h"
/* Maximum buffer sizes required for ECC KEM. */
#define ECC_POINT_LEN_MAX (1+2*64)
#define ECC_HASH_LEN_MAX 64
/* FIXME: Better change the function name because mpi_ is used by
gcrypt macros. */
gcry_mpi_t
@ -444,13 +450,12 @@ do_encrypt_kem (PKT_public_key *pk, gcry_mpi_t data, int seskey_algo,
size_t seskey_len;
unsigned char *enc_seskey = NULL;
size_t enc_seskey_len;
int ecc_hash_algo;
unsigned char ecc_ct[GCRY_KEM_ECC_X25519_ENCAPS_LEN];
size_t ecc_ct_len = GCRY_KEM_ECC_X25519_ENCAPS_LEN;
unsigned char ecc_ecdh[GCRY_KEM_RAW_X25519_SHARED_LEN];
size_t ecc_ecdh_len = GCRY_KEM_RAW_X25519_SHARED_LEN;
unsigned char ecc_ss[GCRY_KEM_RAW_X25519_SHARED_LEN];
size_t ecc_ss_len = GCRY_KEM_RAW_X25519_SHARED_LEN;
unsigned char ecc_ct[ECC_POINT_LEN_MAX];
unsigned char ecc_ecdh[ECC_POINT_LEN_MAX];
unsigned char ecc_ss[ECC_HASH_LEN_MAX];
size_t ecc_ct_len, ecc_ecdh_len, ecc_ss_len;
unsigned char kyber_ct[GCRY_KEM_MLKEM1024_ENCAPS_LEN];
unsigned char kyber_ss[GCRY_KEM_MLKEM1024_SHARED_LEN];
@ -484,7 +489,12 @@ do_encrypt_kem (PKT_public_key *pk, gcry_mpi_t data, int seskey_algo,
"legacy OID for cv25519 accepted during develpment\n");
ecc_pubkey = gcry_mpi_get_opaque (pk->pkey[1], &nbits);
ecc_pubkey_len = (nbits+7)/8;
if (ecc_pubkey_len != 33)
if (ecc_pubkey_len == 33 && *ecc_pubkey == 0x40)
{
ecc_pubkey++; /* Remove the 0x40 prefix. */
ecc_pubkey_len--;
}
if (ecc_pubkey_len != 32)
{
if (opt.verbose)
log_info ("%s: ECC public key length invalid (%zu)\n",
@ -492,8 +502,25 @@ do_encrypt_kem (PKT_public_key *pk, gcry_mpi_t data, int seskey_algo,
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
ecc_pubkey++; /* Remove the 0x40 prefix. */
ecc_pubkey_len--;
ecc_ct_len = ecc_ecdh_len = 32;
ecc_ss_len = 32;
ecc_hash_algo = GCRY_MD_SHA3_256;
}
else if (ecc_algo == GCRY_KEM_RAW_X448)
{
ecc_pubkey = gcry_mpi_get_opaque (pk->pkey[1], &nbits);
ecc_pubkey_len = (nbits+7)/8;
if (ecc_pubkey_len != 56)
{
if (opt.verbose)
log_info ("%s: ECC public key length invalid (%zu)\n",
__func__, ecc_pubkey_len);
err = gpg_error (GPG_ERR_INV_DATA);
goto leave;
}
ecc_ct_len = ecc_ecdh_len = 56;
ecc_ss_len = 64;
ecc_hash_algo = GCRY_MD_SHA3_512;
}
else
{
@ -528,7 +555,7 @@ do_encrypt_kem (PKT_public_key *pk, gcry_mpi_t data, int seskey_algo,
log_printhex (ecc_ecdh, ecc_ecdh_len, "ECC ecdh:");
}
err = gnupg_ecc_kem_kdf (ecc_ss, ecc_ss_len,
GCRY_MD_SHA3_256,
ecc_hash_algo,
ecc_ecdh, ecc_ecdh_len,
ecc_ct, ecc_ct_len,
ecc_pubkey, ecc_pubkey_len);
@ -665,9 +692,9 @@ do_encrypt_kem (PKT_public_key *pk, gcry_mpi_t data, int seskey_algo,
}
leave:
wipememory (ecc_ct, ecc_ct_len);
wipememory (ecc_ecdh, ecc_ecdh_len);
wipememory (ecc_ss, ecc_ss_len);
wipememory (ecc_ct, sizeof ecc_ct);
wipememory (ecc_ecdh, sizeof ecc_ecdh);
wipememory (ecc_ss, sizeof ecc_ss);
wipememory (kyber_ct, sizeof kyber_ct);
wipememory (kyber_ss, sizeof kyber_ss);
wipememory (kek, kek_len);