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gpg,ecc: Handle external representation as SOS with opaque MPI.

Browse source 
* g10/pkglue.h (sexp_extract_param_sos): New.
* g10/build-packet.c (sos_write): New.
(do_key, do_pubkey_enc, do_signature): Use sos_write for ECC.
* g10/export.c (cleartext_secret_key_to_openpgp): Use
sexp_extract_param_sos.
(transfer_format_to_openpgp): Use opaque MPI for ECC.
* g10/keygen.c (ecckey_from_sexp): Use sexp_extract_param_sos.
* g10/keyid.c (hash_public_key): Handle opaque MPI for SOS.
* g10/parse-packet.c (sos_read): New.
(parse_pubkeyenc,parse_signature,parse_key): Use sos_read for ECC.
* g10/pkglue.c (sexp_extract_param_sos): New.
(pk_verify): Handle opaque MPI for SOS.
(pk_encrypt): Use sexp_extract_param_sos.
* g10/seskey.c (encode_session_key): Use opaque MPI.
* g10/sign.c (do_sign): Use sexp_extract_param_sos.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2020-06-09 10:32:47 +09:00
parent 5c2080f467
commit f5bc945554
9 changed files with 316 additions and 59 deletions
Download patch file Download diff file Expand all files Collapse all files

78
g10/pkglue.c
View file

@ -47,6 +47,56 @@ get_mpi_from_sexp (gcry_sexp_t sexp, const char *item, int mpifmt)
}
/* Extract SOS representation from SEXP for PARAM, return the result
in R_SOS. */
gpg_error_t
sexp_extract_param_sos (gcry_sexp_t sexp, const char *param, gcry_mpi_t *r_sos)
{
gpg_error_t err;
gcry_sexp_t l2 = gcry_sexp_find_token (sexp, param, 0);
*r_sos = NULL;
if (!l2)
err = gpg_error (GPG_ERR_NO_OBJ);
else
{
size_t buflen;
void *p0 = gcry_sexp_nth_buffer (l2, 1, &buflen);
if (!p0)
err = gpg_error_from_syserror ();
else
{
gcry_mpi_t sos;
unsigned int nbits = buflen*8;
unsigned char *p = p0;
if (nbits >= 8 && !(*p & 0x80))
if (--nbits >= 7 && !(*p & 0x40))
if (--nbits >= 6 && !(*p & 0x20))
if (--nbits >= 5 && !(*p & 0x10))
if (--nbits >= 4 && !(*p & 0x08))
if (--nbits >= 3 && !(*p & 0x04))
if (--nbits >= 2 && !(*p & 0x02))
if (--nbits >= 1 && !(*p & 0x01))
--nbits;
sos = gcry_mpi_set_opaque (NULL, p0, nbits);
if (sos)
{
gcry_mpi_set_flag (sos, GCRYMPI_FLAG_USER2);
*r_sos = sos;
err = 0;
}
else
err = gpg_error_from_syserror ();
}
gcry_sexp_release (l2);
}
return err;
}
/****************
* Emulate our old PK interface here - sometime in the future we might
@ -152,6 +202,7 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
gcry_mpi_t s = data[1];
size_t rlen, slen, n; /* (bytes) */
char buf[64];
unsigned int nbits;
log_assert (neededfixedlen <= sizeof buf);
@ -182,6 +233,17 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
memset (buf, 0, neededfixedlen - n);
r = gcry_mpi_set_opaque_copy (NULL, buf, neededfixedlen * 8);
}
else if (rlen < neededfixedlen
&& gcry_mpi_get_flag (r, GCRYMPI_FLAG_OPAQUE))
{
const unsigned char *p;
p = gcry_mpi_get_opaque (r, &nbits);
n = (nbits+7)/8;
memcpy (buf + (neededfixedlen - n), p, n);
memset (buf, 0, neededfixedlen - n);
gcry_mpi_set_opaque_copy (r, buf, neededfixedlen * 8);
}
if (slen < neededfixedlen
&& !gcry_mpi_get_flag (s, GCRYMPI_FLAG_OPAQUE)
&& !(rc=gcry_mpi_print (GCRYMPI_FMT_USG, buf, sizeof buf, &n, s)))
@ -191,6 +253,17 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
memset (buf, 0, neededfixedlen - n);
s = gcry_mpi_set_opaque_copy (NULL, buf, neededfixedlen * 8);
}
else if (slen < neededfixedlen
&& gcry_mpi_get_flag (s, GCRYMPI_FLAG_OPAQUE))
{
const unsigned char *p;
p = gcry_mpi_get_opaque (s, &nbits);
n = (nbits+7)/8;
memcpy (buf + (neededfixedlen - n), p, n);
memset (buf, 0, neededfixedlen - n);
gcry_mpi_set_opaque_copy (s, buf, neededfixedlen * 8);
}
if (!rc)
rc = gcry_sexp_build (&s_sig, NULL,
@ -315,7 +388,7 @@ pk_encrypt (pubkey_algo_t algo, gcry_mpi_t *resarr, gcry_mpi_t data,
/* Get the shared point and the ephemeral public key. */
shared = get_mpi_from_sexp (s_ciph, "s", GCRYMPI_FMT_USG);
public = get_mpi_from_sexp (s_ciph, "e", GCRYMPI_FMT_USG);
rc = sexp_extract_param_sos (s_ciph, "e", &public);
gcry_sexp_release (s_ciph);
s_ciph = NULL;
if (DBG_CRYPTO)
@ -329,7 +402,8 @@ pk_encrypt (pubkey_algo_t algo, gcry_mpi_t *resarr, gcry_mpi_t data,
fingerprint_from_pk (pk, fp, &fpn);
if (fpn != 20)
rc = gpg_error (GPG_ERR_INV_LENGTH);
else
if (!rc)
rc = pk_ecdh_encrypt_with_shared_point (shared,
fp, data, pkey, &result);
gcry_mpi_release (shared);