The Tor Browser: security/nss/lib/freebl/jpake.c@b8a032363ba2 (annotated)

security/nss/lib/freebl/jpake.c@b8a032363ba2 (annotated)

security/nss/lib/freebl/jpake.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* 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;
 }

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security/nss/lib/freebl/jpake.c@b8a032363ba2 (annotated)

security/nss/lib/freebl/jpake.c