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gpg: Some support to allow Kyber decryption.

Browse Source 
* g10/call-agent.c (agent_pkdecrypt): Support dual keygrips and switch
to KEM mode.
* g10/ecdh.c (pk_ecdh_decrypt): Add an extra length check.
* g10/keyid.c (do_hash_public_key): Fix Kyber fingerprint computation.

* g10/mainproc.c (release_list): Free all 4 data elements.
(proc_pubkey_enc): Copy all 4 data elements.
* g10/misc.c (openpgp_pk_test_algo2): Map Kyber to KEM.

* g10/parse-packet.c (parse_pubkeyenc): Fix Kyber parser.
* g10/pubkey-enc.c (get_session_key): Allow Kyber.
(get_it): Support Kyber.
--

GnuPG-bug-id: 6815
This commit is contained in:
Werner Koch 2024-04-09 11:00:35 +02:00
parent 1a37f0080b
commit 52c4b09080
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
7 changed files with 67 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
g10/call-agent.c
View File

@ -2878,6 +2878,7 @@ agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
membuf_t data;
size_t n, len;
char *p, *buf, *endp;
const char *keygrip2 = NULL;
struct default_inq_parm_s dfltparm;
memset (&dfltparm, 0, sizeof dfltparm);
@ -2886,13 +2887,26 @@ agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
dfltparm.keyinfo.mainkeyid = mainkeyid;
dfltparm.keyinfo.pubkey_algo = pubkey_algo;
if (!keygrip || strlen(keygrip) != 40
|| !s_ciphertext || !r_buf || !r_buflen || !r_padding)
if (!keygrip || !s_ciphertext || !r_buf || !r_buflen || !r_padding)
return gpg_error (GPG_ERR_INV_VALUE);
*r_buf = NULL;
*r_padding = -1;
/* Parse the keygrip in case of a dual algo. */
keygrip2 = strchr (keygrip, ',');
if (!keygrip2)
keygrip2 = keygrip + strlen (keygrip);
if (keygrip2 - keygrip != 40)
return gpg_error (GPG_ERR_INV_VALUE);
if (*keygrip2)
{
keygrip2++;
if (strlen (keygrip2) != 40)
return gpg_error (GPG_ERR_INV_VALUE);
}
err = start_agent (ctrl, 0);
if (err)
return err;
@ -2903,11 +2917,19 @@ agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
if (err)
return err;
snprintf (line, sizeof line, "SETKEY %s", keygrip);
snprintf (line, sizeof line, "SETKEY %.40s", keygrip);
err = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
if (err)
return err;
if (*keygrip2)
{
snprintf (line, sizeof line, "SETKEY --another %.40s", keygrip2);
err = assuan_transact (agent_ctx, line, NULL, NULL,NULL,NULL,NULL,NULL);
if (err)
return err;
}
if (desc)
{
snprintf (line, DIM(line), "SETKEYDESC %s", desc);
@ -2926,7 +2948,8 @@ agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
err = make_canon_sexp (s_ciphertext, &parm.ciphertext, &parm.ciphertextlen);
if (err)
return err;
err = assuan_transact (agent_ctx, "PKDECRYPT",
err = assuan_transact (agent_ctx,
*keygrip2? "PKDECRYPT --kem=PQC-PGP":"PKDECRYPT",
put_membuf_cb, &data,
inq_ciphertext_cb, &parm,
padding_info_cb, r_padding);

2
g10/ecdh.c
View File

@ -537,7 +537,7 @@ pk_ecdh_decrypt (gcry_mpi_t *r_result, const byte sk_fp[MAX_FINGERPRINT_LEN],
nbytes = (nbits+7)/8;
data_buf_size = nbytes;
if ((data_buf_size & 7) != 1)
if ((data_buf_size & 7) != 1 || data_buf_size <= 1 + 8)
{
log_error ("can't use a shared secret of %d bytes for ecdh\n",
data_buf_size);

17
g10/keyid.c
View File

@ -336,17 +336,24 @@ do_hash_public_key (gcry_md_hd_t md, PKT_public_key *pk, int use_v5)
{
/* Ugly: We need to re-construct the wire format of the
* key parameter. It would be easier to use a second
* second index for pp and nn which could bump
* independet of i. */
* index for pp and nn which we could bump independet of
* i. */
const char *p;
p = gcry_mpi_get_opaque (pk->pkey[i], &nbits);
pp[i] = xmalloc ((nbits+7)/8 + 1);
nn[i] = (nbits+7)/8;
pp[i] = xmalloc (4 + nn[i] + 1);
if (p)
memcpy (pp[i], p, (nbits+7)/8);
{
pp[i][0] = nn[i] >> 24;
pp[i][1] = nn[i] >> 16;
pp[i][2] = nn[i] >> 8;
pp[i][3] = nn[i];
memcpy (pp[i] + 4 , p, nn[i]);
nn[i] += 4;
}
else
pp[i] = NULL;
nn[i] = (nbits+7)/8;
n += nn[i];
}
else if (gcry_mpi_get_flag (pk->pkey[i], GCRYMPI_FLAG_OPAQUE))

6
g10/mainproc.c
View File

@ -143,6 +143,8 @@ release_list( CTX c )
mpi_release (c->pkenc_list->data[0]);
mpi_release (c->pkenc_list->data[1]);
mpi_release (c->pkenc_list->data[2]);
mpi_release (c->pkenc_list->data[3]);
xfree (c->pkenc_list);
c->pkenc_list = tmp;
}
@ -527,11 +529,13 @@ proc_pubkey_enc (CTX c, PACKET *pkt)
x->keyid[1] = enc->keyid[1];
x->pubkey_algo = enc->pubkey_algo;
x->result = -1;
x->data[0] = x->data[1] = NULL;
x->data[0] = x->data[1] = x->data[2] = x->data[3] = NULL;
if (enc->data[0])
{
x->data[0] = mpi_copy (enc->data[0]);
x->data[1] = mpi_copy (enc->data[1]);
x->data[2] = mpi_copy (enc->data[2]);
x->data[3] = mpi_copy (enc->data[3]);
}
x->next = c->pkenc_list;
c->pkenc_list = x;

2
g10/misc.c
View File

@ -750,6 +750,8 @@ openpgp_pk_test_algo2 (pubkey_algo_t algo, unsigned int use)
ga = GCRY_PK_ELG;
break;
case PUBKEY_ALGO_KYBER: ga = GCRY_PK_KEM; break;
default:
break;
}

10
g10/parse-packet.c
View File

@ -1444,6 +1444,7 @@ parse_symkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
}
/* Parse a public key encrypted packet (Tag 1). */
static int
parse_pubkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
PACKET * packet)
@ -1514,9 +1515,14 @@ parse_pubkeyenc (IOBUF inp, int pkttype, unsigned long pktlen,
{
log_assert (ndata == 4);
/* Get the ephemeral public key. */
rc = read_octet_string (inp, &pktlen, 4, 0, 0, k->data + 0);
if (rc)
n = pktlen;
k->data[0] = sos_read (inp, &n, 0);
pktlen -= n;
if (!k->data[0])
{
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
/* Get the Kyber ciphertext. */
rc = read_octet_string (inp, &pktlen, 4, 0, 0, k->data + 1);
if (rc)

12
g10/pubkey-enc.c
View File

@ -117,6 +117,7 @@ get_session_key (ctrl_t ctrl, struct pubkey_enc_list *list, DEK *dek)
{
if (!(k->pubkey_algo == PUBKEY_ALGO_ELGAMAL_E
|| k->pubkey_algo == PUBKEY_ALGO_ECDH
|| k->pubkey_algo == PUBKEY_ALGO_KYBER
|| k->pubkey_algo == PUBKEY_ALGO_RSA
|| k->pubkey_algo == PUBKEY_ALGO_RSA_E
|| k->pubkey_algo == PUBKEY_ALGO_ELGAMAL))
@ -237,6 +238,16 @@ get_it (ctrl_t ctrl,
err = gcry_sexp_build (&s_data, NULL, "(enc-val(ecdh(s%m)(e%m)))",
enc->data[1], enc->data[0]);
}
else if (sk->pubkey_algo == PUBKEY_ALGO_KYBER)
{
if (!enc->data[0] || !enc->data[1] || !enc->data[2] || !enc->data[3])
err = gpg_error (GPG_ERR_BAD_MPI);
else
err = gcry_sexp_build (&s_data, NULL,
"(enc-val(pqc(e%m)(k%m)(s%m)(fixed-info%s)))",
enc->data[0], enc->data[1], enc->data[3],
"\x1d" /*PUBKEY_ALGO_KYBER*/);
}
else
err = gpg_error (GPG_ERR_BUG);
@ -249,7 +260,6 @@ get_it (ctrl_t ctrl,
/* Decrypt. */
desc = gpg_format_keydesc (ctrl, sk, FORMAT_KEYDESC_NORMAL, 1);
/*FIXME: Support dual keys. */
err = agent_pkdecrypt (NULL, keygrip,
desc, sk->keyid, sk->main_keyid, sk->pubkey_algo,
s_data, &frame, &nframe, &padding);