/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "blapi.h"
#include "secerr.h"
#include "secitem.h"
#include "secmpi.h"
/* Hash an item's length and then its value. Only items smaller than 2^16 bytes
* are allowed. Lengths are hashed in network byte order. This is designed
* to match the OpenSSL J-PAKE implementation.
*/
static mp_err
hashSECItem(HASHContext *hash,
const SECItem *it)
{
unsigned char length[2];
if (it->len > 0xffff)
return MP_BADARG;
length[0] = (
unsigned char)(it->len >> 8);
length[1] = (
unsigned char)(it->len);
hash->hashobj->update(hash->hash_context, length, 2);
hash->hashobj->update(hash->hash_context, it->data, it->len);
return MP_OKAY;
}
/* Hash all public components of the signature, each prefixed with its
length, and then convert the hash to an mp_int. */
static mp_err
hashPublicParams(HASH_HashType hashType,
const SECItem *g,
const SECItem *gv,
const SECItem *gx,
const SECItem *signerID, mp_int *h)
{
mp_err err;
unsigned char hBuf[HASH_LENGTH_MAX];
SECItem hItem;
HASHContext hash;
hash.hashobj = HASH_GetRawHashObject(hashType);
if (hash.hashobj == NULL || hash.hashobj->length >
sizeof hBuf) {
return MP_BADARG;
}
hash.hash_context = hash.hashobj->create();
if (hash.hash_context == NULL) {
return MP_MEM;
}
hItem.data = hBuf;
hItem.len = hash.hashobj->length;
hash.hashobj->begin(hash.hash_context);
CHECK_MPI_OK(hashSECItem(&hash, g));
CHECK_MPI_OK(hashSECItem(&hash, gv));
CHECK_MPI_OK(hashSECItem(&hash, gx));
CHECK_MPI_OK(hashSECItem(&hash, signerID));
hash.hashobj->end(hash.hash_context, hItem.data, &hItem.len,
sizeof hBuf);
SECITEM_TO_MPINT(hItem, h);
cleanup:
if (hash.hash_context != NULL) {
hash.hashobj->destroy(hash.hash_context, PR_TRUE);
}
return err;
}
/* Generate a Schnorr signature for round 1 or round 2 */
SECStatus
JPAKE_Sign(PLArenaPool *arena,
const PQGParams *pqg, HASH_HashType hashType,
const SECItem *signerID,
const SECItem *x,
const SECItem *testRandom,
const SECItem *gxIn, SECItem *gxOut,
SECItem *gv, SECItem *r)
{
SECStatus rv = SECSuccess;
mp_err err;
mp_int p;
mp_int q;
mp_int g;
mp_int X;
mp_int GX;
mp_int V;
mp_int GV;
mp_int h;
mp_int tmp;
mp_int R;
SECItem v;
if (!arena ||
!pqg || !pqg->prime.data || pqg->prime.len == 0 ||
!pqg->subPrime.data || pqg->subPrime.len == 0 ||
!pqg->base.data || pqg->base.len == 0 ||
!signerID || !signerID->data || signerID->len == 0 ||
!x || !x->data || x->len == 0 ||
(testRandom && (!testRandom->data || testRandom->len == 0)) ||
(gxIn == NULL && (!gxOut || gxOut->data != NULL)) ||
(gxIn != NULL && (!gxIn->data || gxIn->len == 0 || gxOut != NULL)) ||
!gv || gv->data != NULL ||
!r || r->data != NULL) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
MP_DIGITS(&p) = 0;
MP_DIGITS(&q) = 0;
MP_DIGITS(&g) = 0;
MP_DIGITS(&X) = 0;
MP_DIGITS(&GX) = 0;
MP_DIGITS(&V) = 0;
MP_DIGITS(&GV) = 0;
MP_DIGITS(&h) = 0;
MP_DIGITS(&tmp) = 0;
MP_DIGITS(&R) = 0;
CHECK_MPI_OK(mp_init(&p));
CHECK_MPI_OK(mp_init(&q));
CHECK_MPI_OK(mp_init(&g));
CHECK_MPI_OK(mp_init(&X));
CHECK_MPI_OK(mp_init(&GX));
CHECK_MPI_OK(mp_init(&V));
CHECK_MPI_OK(mp_init(&GV));
CHECK_MPI_OK(mp_init(&h));
CHECK_MPI_OK(mp_init(&tmp));
CHECK_MPI_OK(mp_init(&R));
SECITEM_TO_MPINT(pqg->prime, &p);
SECITEM_TO_MPINT(pqg->subPrime, &q);
SECITEM_TO_MPINT(pqg->base, &g);
SECITEM_TO_MPINT(*x, &X);
/* gx = g^x */
if (gxIn == NULL) {
CHECK_MPI_OK(mp_exptmod(&g, &X, &p, &GX));
MPINT_TO_SECITEM(&GX, gxOut, arena);
gxIn = gxOut;
}
else {
SECITEM_TO_MPINT(*gxIn, &GX);
}
/* v is a random value in the q subgroup */
if (testRandom == NULL) {
v.data = NULL;
rv = DSA_NewRandom(arena, &pqg->subPrime, &v);
if (rv != SECSuccess) {
goto cleanup;
}
}
else {
v.data = testRandom->data;
v.len = testRandom->len;
}
SECITEM_TO_MPINT(v, &V);
/* gv = g^v (mod q), random v, 1 <= v < q */
CHECK_MPI_OK(mp_exptmod(&g, &V, &p, &GV));
MPINT_TO_SECITEM(&GV, gv, arena);
/* h = H(g, gv, gx, signerID) */
CHECK_MPI_OK(hashPublicParams(hashType, &pqg->base, gv, gxIn, signerID,
&h));
/* r = v - x*h (mod q) */
CHECK_MPI_OK(mp_mulmod(&X, &h, &q, &tmp));
CHECK_MPI_OK(mp_submod(&V, &tmp, &q, &R));
MPINT_TO_SECITEM(&R, r, arena);
cleanup:
mp_clear(&p);
mp_clear(&q);
mp_clear(&g);
mp_clear(&X);
mp_clear(&GX);
mp_clear(&V);
mp_clear(&GV);
mp_clear(&h);
mp_clear(&tmp);
mp_clear(&R);
if (rv == SECSuccess && err != MP_OKAY) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
return rv;
}
/* Verify a Schnorr signature generated by the peer in round 1 or round 2. */
SECStatus
JPAKE_Verify(PLArenaPool *arena,
const PQGParams *pqg, HASH_HashType hashType,
const SECItem *signerID,
const SECItem *peerID,
const SECItem *gx,
const SECItem *gv,
const SECItem *r)
{
SECStatus rv = SECSuccess;
mp_err err;
mp_int p;
mp_int q;
mp_int g;
mp_int p_minus_1;
mp_int GX;
mp_int h;
mp_int one;
mp_int R;
mp_int gr;
mp_int gxh;
mp_int gr_gxh;
SECItem calculated;
if (!arena ||
!pqg || !pqg->prime.data || pqg->prime.len == 0 ||
!pqg->subPrime.data || pqg->subPrime.len == 0 ||
!pqg->base.data || pqg->base.len == 0 ||
!signerID || !signerID->data || signerID->len == 0 ||
!peerID || !peerID->data || peerID->len == 0 ||
!gx || !gx->data || gx->len == 0 ||
!gv || !gv->data || gv->len == 0 ||
!r || !r->data || r->len == 0 ||
SECITEM_CompareItem(signerID, peerID) == SECEqual) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
MP_DIGITS(&p) = 0;
MP_DIGITS(&q) = 0;
MP_DIGITS(&g) = 0;
MP_DIGITS(&p_minus_1) = 0;
MP_DIGITS(&GX) = 0;
MP_DIGITS(&h) = 0;
MP_DIGITS(&one) = 0;
MP_DIGITS(&R) = 0;
MP_DIGITS(&gr) = 0;
MP_DIGITS(&gxh) = 0;
MP_DIGITS(&gr_gxh) = 0;
calculated.data = NULL;
CHECK_MPI_OK(mp_init(&p));
CHECK_MPI_OK(mp_init(&q));
CHECK_MPI_OK(mp_init(&g));
CHECK_MPI_OK(mp_init(&p_minus_1));
CHECK_MPI_OK(mp_init(&GX));
CHECK_MPI_OK(mp_init(&h));
CHECK_MPI_OK(mp_init(&one));
CHECK_MPI_OK(mp_init(&R));
CHECK_MPI_OK(mp_init(&gr));
CHECK_MPI_OK(mp_init(&gxh));
CHECK_MPI_OK(mp_init(&gr_gxh));
SECITEM_TO_MPINT(pqg->prime, &p);
SECITEM_TO_MPINT(pqg->subPrime, &q);
SECITEM_TO_MPINT(pqg->base, &g);
SECITEM_TO_MPINT(*gx, &GX);
SECITEM_TO_MPINT(*r, &R);
CHECK_MPI_OK(mp_sub_d(&p, 1, &p_minus_1));
CHECK_MPI_OK(mp_exptmod(&GX, &q, &p, &one));
/* Check g^x is in [1, p-2], R is in [0, q-1], and (g^x)^q mod p == 1 */
if (!(mp_cmp_z(&GX) > 0 &&
mp_cmp(&GX, &p_minus_1) < 0 &&
mp_cmp(&R, &q) < 0 &&
mp_cmp_d(&one, 1) == 0)) {
goto badSig;
}
CHECK_MPI_OK(hashPublicParams(hashType, &pqg->base, gv, gx, peerID,
&h));
/* Calculate g^v = g^r * g^x^h */
CHECK_MPI_OK(mp_exptmod(&g, &R, &p, &gr));
CHECK_MPI_OK(mp_exptmod(&GX, &h, &p, &gxh));
CHECK_MPI_OK(mp_mulmod(&gr, &gxh, &p, &gr_gxh));
/* Compare calculated g^v to given g^v */
MPINT_TO_SECITEM(&gr_gxh, &calculated, arena);
if (calculated.len == gv->len &&
NSS_SecureMemcmp(calculated.data, gv->data, calculated.len) == 0) {
rv = SECSuccess;
}
else {
badSig:
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
rv = SECFailure;
}
cleanup:
mp_clear(&p);
mp_clear(&q);
mp_clear(&g);
mp_clear(&p_minus_1);
mp_clear(&GX);
mp_clear(&h);
mp_clear(&one);
mp_clear(&R);
mp_clear(&gr);
mp_clear(&gxh);
mp_clear(&gr_gxh);
if (rv == SECSuccess && err != MP_OKAY) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
return rv;
}
/* Calculate base = gx1*gx3*gx4 (mod p), i.e. g^(x1+x3+x4) (mod p) */
static mp_err
jpake_Round2Base(
const SECItem *gx1,
const SECItem *gx3,
const SECItem *gx4,
const mp_int *p, mp_int *base)
{
mp_err err;
mp_int GX1;
mp_int GX3;
mp_int GX4;
mp_int tmp;
MP_DIGITS(&GX1) = 0;
MP_DIGITS(&GX3) = 0;
MP_DIGITS(&GX4) = 0;
MP_DIGITS(&tmp) = 0;
CHECK_MPI_OK(mp_init(&GX1));
CHECK_MPI_OK(mp_init(&GX3));
CHECK_MPI_OK(mp_init(&GX4));
CHECK_MPI_OK(mp_init(&tmp));
SECITEM_TO_MPINT(*gx1, &GX1);
SECITEM_TO_MPINT(*gx3, &GX3);
SECITEM_TO_MPINT(*gx4, &GX4);
/* In round 2, the peer/attacker sends us g^x3 and g^x4 and the protocol
requires that these values are distinct. */
if (mp_cmp(&GX3, &GX4) == 0) {
return MP_BADARG;
}
CHECK_MPI_OK(mp_mul(&GX1, &GX3, &tmp));
CHECK_MPI_OK(mp_mul(&tmp, &GX4, &tmp));
CHECK_MPI_OK(mp_mod(&tmp, p, base));
cleanup:
mp_clear(&GX1);
mp_clear(&GX3);
mp_clear(&GX4);
mp_clear(&tmp);
return err;
}
SECStatus
JPAKE_Round2(PLArenaPool *arena,
const SECItem *p,
const SECItem *q,
const SECItem *gx1,
const SECItem *gx3,
const SECItem *gx4, SECItem *base,
const SECItem *x2,
const SECItem *s, SECItem *x2s)
{
mp_err err;
mp_int P;
mp_int Q;
mp_int X2;
mp_int S;
mp_int result;
if (!arena ||
!p || !p->data || p->len == 0 ||
!q || !q->data || q->len == 0 ||
!gx1 || !gx1->data || gx1->len == 0 ||
!gx3 || !gx3->data || gx3->len == 0 ||
!gx4 || !gx4->data || gx4->len == 0 ||
!base || base->data != NULL ||
(x2s != NULL && (x2s->data != NULL ||
!x2 || !x2->data || x2->len == 0 ||
!s || !s->data || s->len == 0))) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
MP_DIGITS(&P) = 0;
MP_DIGITS(&Q) = 0;
MP_DIGITS(&X2) = 0;
MP_DIGITS(&S) = 0;
MP_DIGITS(&result) = 0;
CHECK_MPI_OK(mp_init(&P));
CHECK_MPI_OK(mp_init(&Q));
CHECK_MPI_OK(mp_init(&result));
if (x2s != NULL) {
CHECK_MPI_OK(mp_init(&X2));
CHECK_MPI_OK(mp_init(&S));
SECITEM_TO_MPINT(*q, &Q);
SECITEM_TO_MPINT(*x2, &X2);
SECITEM_TO_MPINT(*s, &S);
/* S must be in [1, Q-1] */
if (mp_cmp_z(&S) <= 0 || mp_cmp(&S, &Q) >= 0) {
err = MP_BADARG;
goto cleanup;
}
CHECK_MPI_OK(mp_mulmod(&X2, &S, &Q, &result));
MPINT_TO_SECITEM(&result, x2s, arena);
}
SECITEM_TO_MPINT(*p, &P);
CHECK_MPI_OK(jpake_Round2Base(gx1, gx3, gx4, &P, &result));
MPINT_TO_SECITEM(&result, base, arena);
cleanup:
mp_clear(&P);
mp_clear(&Q);
mp_clear(&X2);
mp_clear(&S);
mp_clear(&result);
if (err != MP_OKAY) {
MP_TO_SEC_ERROR(err);
return SECFailure;
}
return SECSuccess;
}
SECStatus
JPAKE_Final(PLArenaPool *arena,
const SECItem *p,
const SECItem *q,
const SECItem *x2,
const SECItem *gx4,
const SECItem *x2s,
const SECItem *B, SECItem *K)
{
mp_err err;
mp_int P;
mp_int Q;
mp_int tmp;
mp_int exponent;
mp_int divisor;
mp_int base;
if (!arena ||
!p || !p->data || p->len == 0 ||
!q || !q->data || q->len == 0 ||
!x2 || !x2->data || x2->len == 0 ||
!gx4 || !gx4->data || gx4->len == 0 ||
!x2s || !x2s->data || x2s->len == 0 ||
!B || !B->data || B->len == 0 ||
!K || K->data != NULL) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
MP_DIGITS(&P) = 0;
MP_DIGITS(&Q) = 0;
MP_DIGITS(&tmp) = 0;
MP_DIGITS(&exponent) = 0;
MP_DIGITS(&divisor) = 0;
MP_DIGITS(&base) = 0;
CHECK_MPI_OK(mp_init(&P));
CHECK_MPI_OK(mp_init(&Q));
CHECK_MPI_OK(mp_init(&tmp));
CHECK_MPI_OK(mp_init(&exponent));
CHECK_MPI_OK(mp_init(&divisor));
CHECK_MPI_OK(mp_init(&base));
/* exponent = -x2s (mod q) */
SECITEM_TO_MPINT(*q, &Q);
SECITEM_TO_MPINT(*x2s, &tmp);
/* q == 0 (mod q), so q - x2s == -x2s (mod q) */
CHECK_MPI_OK(mp_sub(&Q, &tmp, &exponent));
/* divisor = gx4^-x2s = 1/(gx4^x2s) (mod p) */
SECITEM_TO_MPINT(*p, &P);
SECITEM_TO_MPINT(*gx4, &tmp);
CHECK_MPI_OK(mp_exptmod(&tmp, &exponent, &P, &divisor));
/* base = B*divisor = B/(gx4^x2s) (mod p) */
SECITEM_TO_MPINT(*B, &tmp);
CHECK_MPI_OK(mp_mulmod(&divisor, &tmp, &P, &base));
/* tmp = base^x2 (mod p) */
SECITEM_TO_MPINT(*x2, &exponent);
CHECK_MPI_OK(mp_exptmod(&base, &exponent, &P, &tmp));
MPINT_TO_SECITEM(&tmp, K, arena);
cleanup:
mp_clear(&P);
mp_clear(&Q);
mp_clear(&tmp);
mp_clear(&exponent);
mp_clear(&divisor);
mp_clear(&base);
if (err != MP_OKAY) {
MP_TO_SEC_ERROR(err);
return SECFailure;
}
return SECSuccess;
}
