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/* 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
#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "blapi.h"
#include "blapii.h"
#include "prerr.h"
#include "secerr.h"
#include "secmpi.h"
#include "secitem.h"
#include "mplogic.h"
#include "ec.h"
#include "ecl.h"
#include "verified/Hacl_P384.h"
#include "verified/Hacl_P521.h"
#include "secport.h"
#include "verified/Hacl_Ed25519.h"
#define EC_DOUBLECHECK PR_FALSE
SECStatus
ec_secp384r1_scalar_validate(const SECItem *scalar)
{
if (!scalar || !scalar->data) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (scalar->len != 48) {
PORT_SetError(SEC_ERROR_BAD_KEY);
return SECFailure;
}
bool b = Hacl_P384_validate_private_key(scalar->data);
if (!b) {
PORT_SetError(SEC_ERROR_BAD_KEY);
return SECFailure;
}
return SECSuccess;
}
SECStatus
ec_secp521r1_scalar_validate(const SECItem *scalar)
{
if (!scalar || !scalar->data) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (scalar->len != 66) {
PORT_SetError(SEC_ERROR_BAD_KEY);
return SECFailure;
}
bool b = Hacl_P521_validate_private_key(scalar->data);
if (!b) {
PORT_SetError(SEC_ERROR_BAD_KEY);
return SECFailure;
}
return SECSuccess;
}
SECStatus
ec_ED25519_pt_validate(const SECItem *px)
{
if (!px || !px->data || px->len != Ed25519_PUBLIC_KEYLEN) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
return SECSuccess;
}
SECStatus
ec_ED25519_scalar_validate(const SECItem *scalar)
{
if (!scalar || !scalar->data || scalar->len != Ed25519_PRIVATE_KEYLEN) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
return SECSuccess;
}
static const ECMethod kMethods[] = {
{ ECCurve25519,
ec_Curve25519_pt_mul,
ec_Curve25519_pt_validate,
ec_Curve25519_scalar_validate,
NULL,
NULL },
{
ECCurve_NIST_P256,
ec_secp256r1_pt_mul,
ec_secp256r1_pt_validate,
ec_secp256r1_scalar_validate,
ec_secp256r1_sign_digest,
ec_secp256r1_verify_digest,
},
{
ECCurve_NIST_P384,
NULL,
NULL,
ec_secp384r1_scalar_validate,
NULL,
NULL,
},
{
ECCurve_NIST_P521,
NULL,
NULL,
ec_secp521r1_scalar_validate,
NULL,
NULL,
},
{ ECCurve_Ed25519,
NULL,
ec_ED25519_pt_validate,
ec_ED25519_scalar_validate,
NULL,
NULL },
};
static const ECMethod *
ec_get_method_from_name(ECCurveName name)
{
unsigned long i;
for (i = 0; i < sizeof(kMethods) / sizeof(kMethods[0]); ++i) {
if (kMethods[i].name == name) {
return &kMethods[i];
}
}
return NULL;
}
/*
* Returns true if pointP is the point at infinity, false otherwise
*/
PRBool
ec_point_at_infinity(SECItem *pointP)
{
unsigned int i;
for (i = 1; i < pointP->len; i++) {
if (pointP->data[i] != 0x00)
return PR_FALSE;
}
return PR_TRUE;
}
/*
* Computes scalar point multiplication pointQ = k1 * G + k2 * pointP for
* the curve whose parameters are encoded in params with base point G.
*/
SECStatus
ec_points_mul(const ECParams *params, const mp_int *k1, const mp_int *k2,
const SECItem *pointP, SECItem *pointQ)
{
mp_int Px, Py, Qx, Qy;
mp_int Gx, Gy, order, irreducible, a, b;
ECGroup *group = NULL;
SECStatus rv = SECFailure;
mp_err err = MP_OKAY;
unsigned int len;
#if EC_DEBUG
int i;
char mpstr[256];
printf("ec_points_mul: params [len=%d]:", params->DEREncoding.len);
for (i = 0; i < params->DEREncoding.len; i++)
printf("%02x:", params->DEREncoding.data[i]);
printf("\n");
if (k1 != NULL) {
mp_tohex((mp_int *)k1, mpstr);
printf("ec_points_mul: scalar k1: %s\n", mpstr);
mp_todecimal((mp_int *)k1, mpstr);
printf("ec_points_mul: scalar k1: %s (dec)\n", mpstr);
}
if (k2 != NULL) {
mp_tohex((mp_int *)k2, mpstr);
printf("ec_points_mul: scalar k2: %s\n", mpstr);
mp_todecimal((mp_int *)k2, mpstr);
printf("ec_points_mul: scalar k2: %s (dec)\n", mpstr);
}
if (pointP != NULL) {
printf("ec_points_mul: pointP [len=%d]:", pointP->len);
for (i = 0; i < pointP->len; i++)
printf("%02x:", pointP->data[i]);
printf("\n");
}
#endif
/* NOTE: We only support uncompressed points for now */
len = (((unsigned int)params->fieldID.size) + 7) >> 3;
if (pointP != NULL) {
if ((pointP->data[0] != EC_POINT_FORM_UNCOMPRESSED) ||
(pointP->len != (2 * len + 1))) {
PORT_SetError(SEC_ERROR_UNSUPPORTED_EC_POINT_FORM);
return SECFailure;
};
}
MP_DIGITS(&Px) = 0;
MP_DIGITS(&Py) = 0;
MP_DIGITS(&Qx) = 0;
MP_DIGITS(&Qy) = 0;
MP_DIGITS(&Gx) = 0;
MP_DIGITS(&Gy) = 0;
MP_DIGITS(&order) = 0;
MP_DIGITS(&irreducible) = 0;
MP_DIGITS(&a) = 0;
MP_DIGITS(&b) = 0;
CHECK_MPI_OK(mp_init(&Px));
CHECK_MPI_OK(mp_init(&Py));
CHECK_MPI_OK(mp_init(&Qx));
CHECK_MPI_OK(mp_init(&Qy));
CHECK_MPI_OK(mp_init(&Gx));
CHECK_MPI_OK(mp_init(&Gy));
CHECK_MPI_OK(mp_init(&order));
CHECK_MPI_OK(mp_init(&irreducible));
CHECK_MPI_OK(mp_init(&a));
CHECK_MPI_OK(mp_init(&b));
if ((k2 != NULL) && (pointP != NULL)) {
/* Initialize Px and Py */
CHECK_MPI_OK(mp_read_unsigned_octets(&Px, pointP->data + 1, (mp_size)len));
CHECK_MPI_OK(mp_read_unsigned_octets(&Py, pointP->data + 1 + len, (mp_size)len));
}
/* construct from named params, if possible */
if (params->name != ECCurve_noName) {
group = ECGroup_fromName(params->name);
}
if (group == NULL)
goto cleanup;
if ((k2 != NULL) && (pointP != NULL)) {
CHECK_MPI_OK(ECPoints_mul(group, k1, k2, &Px, &Py, &Qx, &Qy));
} else {
CHECK_MPI_OK(ECPoints_mul(group, k1, NULL, NULL, NULL, &Qx, &Qy));
}
/* our ECC codes uses large stack variables to store intermediate results,
* clear our stack before returning to prevent CSP leakage */
BLAPI_CLEAR_STACK(2048)
/* Construct the SECItem representation of point Q */
pointQ->data[0] = EC_POINT_FORM_UNCOMPRESSED;
CHECK_MPI_OK(mp_to_fixlen_octets(&Qx, pointQ->data + 1,
(mp_size)len));
CHECK_MPI_OK(mp_to_fixlen_octets(&Qy, pointQ->data + 1 + len,
(mp_size)len));
rv = SECSuccess;
#if EC_DEBUG
printf("ec_points_mul: pointQ [len=%d]:", pointQ->len);
for (i = 0; i < pointQ->len; i++)
printf("%02x:", pointQ->data[i]);
printf("\n");
#endif
cleanup:
ECGroup_free(group);
mp_clear(&Px);
mp_clear(&Py);
mp_clear(&Qx);
mp_clear(&Qy);
mp_clear(&Gx);
mp_clear(&Gy);
mp_clear(&order);
mp_clear(&irreducible);
mp_clear(&a);
mp_clear(&b);
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
return rv;
}
/* Generates a new EC key pair. The private key is a supplied
* value and the public key is the result of performing a scalar
* point multiplication of that value with the curve's base point.
*/
SECStatus
ec_NewKey(ECParams *ecParams, ECPrivateKey **privKey,
const unsigned char *privKeyBytes, int privKeyLen)
{
SECStatus rv = SECFailure;
PLArenaPool *arena;
ECPrivateKey *key;
mp_int k;
mp_err err = MP_OKAY;
int len;
#if EC_DEBUG
printf("ec_NewKey called\n");
#endif
MP_DIGITS(&k) = 0;
if (!ecParams || ecParams->name == ECCurve_noName ||
!privKey || !privKeyBytes || privKeyLen <= 0) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
/* Initialize an arena for the EC key. */
if (!(arena = PORT_NewArena(NSS_FREEBL_DEFAULT_CHUNKSIZE)))
return SECFailure;
key = (ECPrivateKey *)PORT_ArenaZAlloc(arena, sizeof(ECPrivateKey));
if (!key) {
PORT_FreeArena(arena, PR_TRUE);
return SECFailure;
}
/* Set the version number (SEC 1 section C.4 says it should be 1) */
SECITEM_AllocItem(arena, &key->version, 1);
key->version.data[0] = 1;
/* Copy all of the fields from the ECParams argument to the
* ECParams structure within the private key.
*/
key->ecParams.arena = arena;
key->ecParams.type = ecParams->type;
key->ecParams.fieldID.size = ecParams->fieldID.size;
key->ecParams.fieldID.type = ecParams->fieldID.type;
if (ecParams->fieldID.type == ec_field_GFp ||
ecParams->fieldID.type == ec_field_plain) {
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.prime,
&ecParams->fieldID.u.prime));
} else {
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.poly,
&ecParams->fieldID.u.poly));
}
key->ecParams.fieldID.k1 = ecParams->fieldID.k1;
key->ecParams.fieldID.k2 = ecParams->fieldID.k2;
key->ecParams.fieldID.k3 = ecParams->fieldID.k3;
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.a,
&ecParams->curve.a));
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.b,
&ecParams->curve.b));
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.seed,
&ecParams->curve.seed));
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.base,
&ecParams->base));
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.order,
&ecParams->order));
key->ecParams.cofactor = ecParams->cofactor;
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.DEREncoding,
&ecParams->DEREncoding));
key->ecParams.name = ecParams->name;
CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curveOID,
&ecParams->curveOID));
SECITEM_AllocItem(arena, &key->publicValue, EC_GetPointSize(ecParams));
len = ecParams->order.len;
SECITEM_AllocItem(arena, &key->privateValue, len);
/* Copy private key */
if (privKeyLen >= len) {
memcpy(key->privateValue.data, privKeyBytes, len);
} else {
memset(key->privateValue.data, 0, (len - privKeyLen));
memcpy(key->privateValue.data + (len - privKeyLen), privKeyBytes, privKeyLen);
}
/* Compute corresponding public key */
/* Use curve specific code for point multiplication */
if (ecParams->name == ECCurve_Ed25519) {
rv = ED_DerivePublicKey(&key->privateValue, &key->publicValue);
if (rv != SECSuccess) {
goto cleanup;
}
NSS_DECLASSIFY(key->publicValue.data, key->publicValue.len); /* Declassifying public key to avoid false positive */
goto done;
}
if (ecParams->fieldID.type == ec_field_plain) {
const ECMethod *method = ec_get_method_from_name(ecParams->name);
if (method == NULL || method->pt_mul == NULL) {
/* unknown curve */
rv = SECFailure;
goto cleanup;
}
rv = method->pt_mul(&key->publicValue, &key->privateValue, NULL);
NSS_DECLASSIFY(key->publicValue.data, key->publicValue.len); /* Declassifying public key to avoid false positive */
if (rv != SECSuccess) {
goto cleanup;
} else {
goto done;
}
}
CHECK_MPI_OK(mp_init(&k));
CHECK_MPI_OK(mp_read_unsigned_octets(&k, key->privateValue.data,
(mp_size)len));
rv = ec_points_mul(ecParams, &k, NULL, NULL, &(key->publicValue));
NSS_DECLASSIFY(key->publicValue.data, key->publicValue.len); /* Declassifying public key to avoid false positive */
if (rv != SECSuccess) {
goto cleanup;
}
done:
*privKey = key;
cleanup:
mp_clear(&k);
if (rv) {
PORT_FreeArena(arena, PR_TRUE);
}
#if EC_DEBUG
printf("ec_NewKey returning %s\n",
(rv == SECSuccess) ? "success" : "failure");
#endif
return rv;
}
/* Generates a new EC key pair. The private key is a supplied
* random value (in seed) and the public key is the result of
* performing a scalar point multiplication of that value with
* the curve's base point.
*/
SECStatus
EC_NewKeyFromSeed(ECParams *ecParams, ECPrivateKey **privKey,
const unsigned char *seed, int seedlen)
{
SECStatus rv = SECFailure;
rv = ec_NewKey(ecParams, privKey, seed, seedlen);
return rv;
}
/* Generate a random private key using the algorithm A.4.1 or A.4.2 of ANSI X9.62,
* modified a la FIPS 186-2 Change Notice 1 to eliminate the bias in the
* random number generator.
*/
SECStatus
ec_GenerateRandomPrivateKey(ECParams *ecParams, SECItem *privKey)
{
SECStatus rv = SECFailure;
unsigned int len = EC_GetScalarSize(ecParams);
if (privKey->len != len || privKey->data == NULL) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
const ECMethod *method = ec_get_method_from_name(ecParams->name);
if (method == NULL || method->scalar_validate == NULL) {
PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE);
return SECFailure;
}
uint8_t leading_coeff_mask;
switch (ecParams->name) {
case ECCurve_Ed25519:
case ECCurve25519:
case ECCurve_NIST_P256:
case ECCurve_NIST_P384:
leading_coeff_mask = 0xff;
break;
case ECCurve_NIST_P521:
leading_coeff_mask = 0x01;
break;
default:
PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE);
return SECFailure;
}
/* The rejection sampling method from FIPS 186-5 A.4.2 */
int count = 100;
do {
rv = RNG_GenerateGlobalRandomBytes(privKey->data, len);
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
return SECFailure;
}
privKey->data[0] &= leading_coeff_mask;
NSS_CLASSIFY(privKey->data, privKey->len);
rv = method->scalar_validate(privKey);
} while (rv != SECSuccess && --count > 0);
if (rv != SECSuccess) { // implies count == 0
PORT_SetError(SEC_ERROR_BAD_KEY);
}
return rv;
}
/* Generates a new EC key pair. The private key is a random value and
* the public key is the result of performing a scalar point multiplication
* of that value with the curve's base point.
*/
SECStatus
EC_NewKey(ECParams *ecParams, ECPrivateKey **privKey)
{
SECStatus rv = SECFailure;
SECItem privKeyRand = { siBuffer, NULL, 0 };
if (!ecParams || ecParams->name == ECCurve_noName || !privKey) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
SECITEM_AllocItem(NULL, &privKeyRand, EC_GetScalarSize(ecParams));
if (privKeyRand.data == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
rv = SECFailure;
goto cleanup;
}
rv = ec_GenerateRandomPrivateKey(ecParams, &privKeyRand);
if (rv != SECSuccess || privKeyRand.data == NULL) {
goto cleanup;
}
/* generate public key */
CHECK_SEC_OK(ec_NewKey(ecParams, privKey, privKeyRand.data, privKeyRand.len));
cleanup:
if (privKeyRand.data) {
SECITEM_ZfreeItem(&privKeyRand, PR_FALSE);
}
#if EC_DEBUG
printf("EC_NewKey returning %s\n",
(rv == SECSuccess) ? "success" : "failure");
#endif
return rv;
}
/* Validates an EC public key as described in Section 5.2.2 of
* X9.62. The ECDH primitive when used without the cofactor does
* not address small subgroup attacks, which may occur when the
* public key is not valid. These attacks can be prevented by
* validating the public key before using ECDH.
*/
SECStatus
EC_ValidatePublicKey(ECParams *ecParams, SECItem *publicValue)
{
mp_int Px, Py;
ECGroup *group = NULL;
SECStatus rv = SECFailure;
mp_err err = MP_OKAY;
unsigned int len;
if (!ecParams || ecParams->name == ECCurve_noName ||
!publicValue || !publicValue->len) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
rv = SECFailure;
return rv;
}
/* Uses curve specific code for point validation. */
if (ecParams->fieldID.type == ec_field_plain) {
const ECMethod *method = ec_get_method_from_name(ecParams->name);
if (method == NULL || method->pt_validate == NULL) {
/* unknown curve */
PORT_SetError(SEC_ERROR_INVALID_ARGS);
rv = SECFailure;
return rv;
}
rv = method->pt_validate(publicValue);
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_BAD_KEY);
}
return rv;
}
/* NOTE: We only support uncompressed points for now */
len = (((unsigned int)ecParams->fieldID.size) + 7) >> 3;
if (publicValue->data[0] != EC_POINT_FORM_UNCOMPRESSED) {
PORT_SetError(SEC_ERROR_UNSUPPORTED_EC_POINT_FORM);
return SECFailure;
} else if (publicValue->len != (2 * len + 1)) {
PORT_SetError(SEC_ERROR_BAD_KEY);
return SECFailure;
}
MP_DIGITS(&Px) = 0;
MP_DIGITS(&Py) = 0;
CHECK_MPI_OK(mp_init(&Px));
CHECK_MPI_OK(mp_init(&Py));
/* Initialize Px and Py */
CHECK_MPI_OK(mp_read_unsigned_octets(&Px, publicValue->data + 1, (mp_size)len));
CHECK_MPI_OK(mp_read_unsigned_octets(&Py, publicValue->data + 1 + len, (mp_size)len));
/* construct from named params */
group = ECGroup_fromName(ecParams->name);
if (group == NULL) {
/*
* ECGroup_fromName fails if ecParams->name is not a valid
* ECCurveName value, or if we run out of memory, or perhaps
* for other reasons. Unfortunately if ecParams->name is a
* valid ECCurveName value, we don't know what the right error
* code should be because ECGroup_fromName doesn't return an
* error code to the caller. Set err to MP_UNDEF because
* that's what ECGroup_fromName uses internally.
*/
if ((ecParams->name <= ECCurve_noName) ||
(ecParams->name >= ECCurve_pastLastCurve)) {
err = MP_BADARG;
} else {
err = MP_UNDEF;
}
goto cleanup;
}
/* validate public point */
if ((err = ECPoint_validate(group, &Px, &Py)) < MP_YES) {
if (err == MP_NO) {
PORT_SetError(SEC_ERROR_BAD_KEY);
rv = SECFailure;
err = MP_OKAY; /* don't change the error code */
}
goto cleanup;
}
rv = SECSuccess;
cleanup:
ECGroup_free(group);
mp_clear(&Px);
mp_clear(&Py);
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
return rv;
}
/*
** Performs an ECDH key derivation by computing the scalar point
** multiplication of privateValue and publicValue (with or without the
** cofactor) and returns the x-coordinate of the resulting elliptic
** curve point in derived secret. If successful, derivedSecret->data
** is set to the address of the newly allocated buffer containing the
** derived secret, and derivedSecret->len is the size of the secret
** produced. It is the caller's responsibility to free the allocated
** buffer containing the derived secret.
*/
SECStatus
ECDH_Derive(SECItem *publicValue,
ECParams *ecParams,
SECItem *privateValue,
PRBool withCofactor,
SECItem *derivedSecret)
{
SECStatus rv = SECFailure;
unsigned int len = 0;
mp_err err = MP_OKAY;
if (!publicValue || !publicValue->len ||
!ecParams || ecParams->name == ECCurve_noName ||
!privateValue || !privateValue->len || !derivedSecret) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
rv = SECFailure;
return rv;
}
/*
* Make sure the point is on the requested curve to avoid
* certain small subgroup attacks.
*/
if (EC_ValidatePublicKey(ecParams, publicValue) != SECSuccess) {
PORT_SetError(SEC_ERROR_BAD_KEY);
rv = SECFailure;
return rv;
}
/* Perform curve specific multiplication using ECMethod */
if (ecParams->fieldID.type == ec_field_plain) {
const ECMethod *method;
memset(derivedSecret, 0, sizeof(*derivedSecret));
derivedSecret = SECITEM_AllocItem(NULL, derivedSecret, EC_GetScalarSize(ecParams));
if (derivedSecret == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
rv = SECFailure;
return rv;
}
method = ec_get_method_from_name(ecParams->name);
if (method == NULL || method->pt_validate == NULL ||
method->pt_mul == NULL) {
PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE);
rv = SECFailure;
goto done;
}
rv = method->pt_mul(derivedSecret, privateValue, publicValue);
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_BAD_KEY);
}
goto done;
}
SECItem pointQ = { siBuffer, NULL, 0 };
mp_int k; /* to hold the private value */
#if EC_DEBUG
int i;
#endif
/*
* We fail if the public value is the point at infinity, since
* this produces predictable results.
*/
if (ec_point_at_infinity(publicValue)) {
PORT_SetError(SEC_ERROR_BAD_KEY);
return SECFailure;
}
MP_DIGITS(&k) = 0;
memset(derivedSecret, 0, sizeof *derivedSecret);
len = (ecParams->fieldID.size + 7) >> 3;
pointQ.len = EC_GetPointSize(ecParams);
if ((pointQ.data = PORT_Alloc(pointQ.len)) == NULL)
goto cleanup;
CHECK_MPI_OK(mp_init(&k));
CHECK_MPI_OK(mp_read_unsigned_octets(&k, privateValue->data,
(mp_size)privateValue->len));
if (withCofactor && (ecParams->cofactor != 1)) {
mp_int cofactor;
/* multiply k with the cofactor */
MP_DIGITS(&cofactor) = 0;
CHECK_MPI_OK(mp_init(&cofactor));
mp_set(&cofactor, ecParams->cofactor);
CHECK_MPI_OK(mp_mul(&k, &cofactor, &k));
mp_clear(&cofactor);
}
/* Multiply our private key and peer's public point */
if (ec_points_mul(ecParams, NULL, &k, publicValue, &pointQ) != SECSuccess) {
goto cleanup;
}
if (ec_point_at_infinity(&pointQ)) {
PORT_SetError(SEC_ERROR_BAD_KEY); /* XXX better error code? */
goto cleanup;
}
/* Allocate memory for the derived secret and copy
* the x co-ordinate of pointQ into it.
*/
SECITEM_AllocItem(NULL, derivedSecret, len);
memcpy(derivedSecret->data, pointQ.data + 1, len);
rv = SECSuccess;
#if EC_DEBUG
printf("derived_secret:\n");
for (i = 0; i < derivedSecret->len; i++)
printf("%02x:", derivedSecret->data[i]);
printf("\n");
#endif
cleanup:
mp_clear(&k);
if (pointQ.data) {
PORT_ZFree(pointQ.data, pointQ.len);
}
done:
if (err) {
MP_TO_SEC_ERROR(err);
}
if (rv != SECSuccess) {
SECITEM_ZfreeItem(derivedSecret, PR_FALSE);
}
return rv;
}
/* Computes the ECDSA signature (a concatenation of two values r and s)
* on the digest using the given key and the random value kb (used in
* computing s).
*/
static SECStatus
ec_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
const SECItem *digest, const unsigned char *kb, const int kblen)
{
SECStatus rv = SECFailure;
ECParams *ecParams = NULL;
mp_err err = MP_OKAY;
int flen = 0; /* length in bytes of the field size */
unsigned olen; /* length in bytes of the base point order */
/* Check args */
if (!key || !signature || !digest || !kb || (kblen <= 0)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
rv = SECFailure;
goto done;
}
ecParams = &(key->ecParams);
flen = (ecParams->fieldID.size + 7) >> 3;
olen = ecParams->order.len;
if (signature->data == NULL) {
/* a call to get the signature length only */
signature->len = 2 * olen;
rv = SECSuccess;
goto done;
}
if (signature->len < 2 * olen) {
PORT_SetError(SEC_ERROR_OUTPUT_LEN);
rv = SECFailure;
goto done;
}
/* Perform curve specific signature using ECMethod */
if (ecParams->fieldID.type == ec_field_plain) {
const ECMethod *method = ec_get_method_from_name(ecParams->name);
if (method == NULL || method->sign_digest == NULL) {
PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE);
rv = SECFailure;
goto done;
}
rv = method->sign_digest(key, signature, digest, kb, kblen);
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
}
goto done;
}
mp_int x1;
mp_int d, k; /* private key, random integer */
mp_int r, s; /* tuple (r, s) is the signature */
mp_int t; /* holding tmp values */
mp_int n;
mp_int ar; /* blinding value */
SECItem kGpoint = { siBuffer, NULL, 0 };
unsigned char *t2 = NULL;
unsigned obits; /* length in bits of the base point order */
#if EC_DEBUG
char mpstr[256];
#endif
/* Initialize MPI integers. */
/* must happen before the first potential call to cleanup */
MP_DIGITS(&x1) = 0;
MP_DIGITS(&d) = 0;
MP_DIGITS(&k) = 0;
MP_DIGITS(&r) = 0;
MP_DIGITS(&s) = 0;
MP_DIGITS(&n) = 0;
MP_DIGITS(&t) = 0;
MP_DIGITS(&ar) = 0;
CHECK_MPI_OK(mp_init(&x1));
CHECK_MPI_OK(mp_init(&d));
CHECK_MPI_OK(mp_init(&k));
CHECK_MPI_OK(mp_init(&r));
CHECK_MPI_OK(mp_init(&s));
CHECK_MPI_OK(mp_init(&n));
CHECK_MPI_OK(mp_init(&t));
CHECK_MPI_OK(mp_init(&ar));
SECITEM_TO_MPINT(ecParams->order, &n);
SECITEM_TO_MPINT(key->privateValue, &d);
CHECK_MPI_OK(mp_read_unsigned_octets(&k, kb, kblen));
/* Make sure k is in the interval [1, n-1] */
if ((mp_cmp_z(&k) <= 0) || (mp_cmp(&k, &n) >= 0)) {
#if EC_DEBUG
printf("k is outside [1, n-1]\n");
mp_tohex(&k, mpstr);
printf("k : %s \n", mpstr);
mp_tohex(&n, mpstr);
printf("n : %s \n", mpstr);
#endif
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
** ANSI X9.62, Section 5.3.2, Step 2
**
** Compute kG
*/
kGpoint.len = EC_GetPointSize(ecParams);
kGpoint.data = PORT_Alloc(kGpoint.len);
if ((kGpoint.data == NULL) ||
(ec_points_mul(ecParams, &k, NULL, NULL, &kGpoint) != SECSuccess))
goto cleanup;
NSS_DECLASSIFY(kGpoint.data, kGpoint.len); /* Declassifying the r component */
/*
** ANSI X9.62, Section 5.3.3, Step 1
**
** Extract the x co-ordinate of kG into x1
*/
CHECK_MPI_OK(mp_read_unsigned_octets(&x1, kGpoint.data + 1,
(mp_size)flen));
/*
** ANSI X9.62, Section 5.3.3, Step 2
**
** r = x1 mod n NOTE: n is the order of the curve
*/
CHECK_MPI_OK(mp_mod(&x1, &n, &r));
/*
** ANSI X9.62, Section 5.3.3, Step 3
**
** verify r != 0
*/
if (mp_cmp_z(&r) == 0) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
** ANSI X9.62, Section 5.3.3, Step 4
**
** s = (k**-1 * (HASH(M) + d*r)) mod n
*/
SECITEM_TO_MPINT(*digest, &s); /* s = HASH(M) */
/* In the definition of EC signing, digests are truncated
* to the length of n in bits.
* (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
CHECK_MPI_OK((obits = mpl_significant_bits(&n)));
if (digest->len * 8 > obits) {
mpl_rsh(&s, &s, digest->len * 8 - obits);
}
#if EC_DEBUG
mp_todecimal(&n, mpstr);
printf("n : %s (dec)\n", mpstr);
mp_todecimal(&d, mpstr);
printf("d : %s (dec)\n", mpstr);
mp_tohex(&x1, mpstr);
printf("x1: %s\n", mpstr);
mp_todecimal(&s, mpstr);
printf("digest: %s (decimal)\n", mpstr);
mp_todecimal(&r, mpstr);
printf("r : %s (dec)\n", mpstr);
mp_tohex(&r, mpstr);
printf("r : %s\n", mpstr);
#endif
if ((t2 = PORT_Alloc(2 * ecParams->order.len)) == NULL) {
rv = SECFailure;
goto cleanup;
}
if (RNG_GenerateGlobalRandomBytes(t2, 2 * ecParams->order.len) != SECSuccess) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
rv = SECFailure;
goto cleanup;
}
CHECK_MPI_OK(mp_read_unsigned_octets(&t, t2, 2 * ecParams->order.len)); /* t <-$ Zn */
PORT_Memset(t2, 0, 2 * ecParams->order.len);
if (RNG_GenerateGlobalRandomBytes(t2, 2 * ecParams->order.len) != SECSuccess) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
rv = SECFailure;
goto cleanup;
}
CHECK_MPI_OK(mp_read_unsigned_octets(&ar, t2, 2 * ecParams->order.len)); /* ar <-$ Zn */
/* Using mp_invmod on k directly would leak bits from k. */
CHECK_MPI_OK(mp_mul(&k, &ar, &k)); /* k = k * ar */
NSS_DECLASSIFY(MP_DIGITS(&k), MP_ALLOC(&k) * sizeof(mp_digit)); /* declassifying k here because it is masked by multiplying with ar */
CHECK_MPI_OK(mp_mulmod(&k, &t, &n, &k)); /* k = k * t mod n */
CHECK_MPI_OK(mp_invmod(&k, &n, &k)); /* k = k**-1 mod n */
CHECK_MPI_OK(mp_mulmod(&k, &t, &n, &k)); /* k = k * t mod n */
/* To avoid leaking secret bits here the addition is blinded. */
CHECK_MPI_OK(mp_mul(&d, &ar, &t)); /* t = d * ar */
NSS_DECLASSIFY(MP_DIGITS(&t), MP_ALLOC(&t) * sizeof(mp_digit)); /* declassifying d here because it is masked by multiplying with ar */
CHECK_MPI_OK(mp_mulmod(&t, &r, &n, &d)); /* d = t * r mod n */
CHECK_MPI_OK(mp_mulmod(&s, &ar, &n, &t)); /* t = s * ar mod n */
CHECK_MPI_OK(mp_add(&t, &d, &s)); /* s = t + d */
CHECK_MPI_OK(mp_mulmod(&s, &k, &n, &s)); /* s = s * k mod n */
#if EC_DEBUG
mp_todecimal(&s, mpstr);
printf("s : %s (dec)\n", mpstr);
mp_tohex(&s, mpstr);
printf("s : %s\n", mpstr);
#endif
/*
** ANSI X9.62, Section 5.3.3, Step 5
**
** verify s != 0
*/
if (mp_cmp_z(&s) == 0) {
PORT_SetError(SEC_ERROR_NEED_RANDOM);
goto cleanup;
}
/*
**
** Signature is tuple (r, s)
*/
CHECK_MPI_OK(mp_to_fixlen_octets(&r, signature->data, olen));
CHECK_MPI_OK(mp_to_fixlen_octets(&s, signature->data + olen, olen));
signature->len = 2 * olen;
rv = SECSuccess;
err = MP_OKAY;
cleanup:
mp_clear(&x1);
mp_clear(&d);
mp_clear(&k);
mp_clear(&r);
mp_clear(&s);
mp_clear(&n);
mp_clear(&t);
mp_clear(&ar);
if (t2) {
PORT_ZFree(t2, 2 * ecParams->order.len);
}
if (kGpoint.data) {
PORT_ZFree(kGpoint.data, kGpoint.len);
}
done:
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
#if EC_DEBUG
printf("ECDSA signing with seed %s\n",
(rv == SECSuccess) ? "succeeded" : "failed");
#endif
return rv;
}
SECStatus
ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
const SECItem *digest, const unsigned char *kb, const int kblen)
{
#if EC_DEBUG || EC_DOUBLECHECK
SECItem *signature2 = SECITEM_AllocItem(NULL, NULL, signature->len);
SECStatus signSuccess = ec_SignDigestWithSeed(key, signature, digest, kb, kblen);
SECStatus signSuccessDouble = ec_SignDigestWithSeed(key, signature2, digest, kb, kblen);
int signaturesEqual = NSS_SecureMemcmp(signature->data, signature2->data, signature->len);
SECStatus rv;
if ((signaturesEqual == 0) && (signSuccess == SECSuccess) && (signSuccessDouble == SECSuccess)) {
rv = SECSuccess;
} else {
rv = SECFailure;
}
#if EC_DEBUG
printf("ECDSA signing with seed %s after signing twice\n", (rv == SECSuccess) ? "succeeded" : "failed");
#endif
SECITEM_FreeItem(signature2, PR_TRUE);
return rv;
#else
return ec_SignDigestWithSeed(key, signature, digest, kb, kblen);
#endif
}
/*
** Computes the ECDSA signature on the digest using the given key
** and a random seed.
*/
SECStatus
ECDSA_SignDigest(ECPrivateKey *key, SECItem *signature, const SECItem *digest)
{
SECStatus rv = SECFailure;
SECItem nonceRand = { siBuffer, NULL, 0 };
if (!key) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
/* Generate random value k */
SECITEM_AllocItem(NULL, &nonceRand, EC_GetScalarSize(&key->ecParams));
if (nonceRand.data == NULL) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
rv = SECFailure;
goto cleanup;
}
rv = ec_GenerateRandomPrivateKey(&key->ecParams, &nonceRand);
if (rv != SECSuccess || nonceRand.data == NULL)
goto cleanup;
/* Generate ECDSA signature with the specified k value */
rv = ECDSA_SignDigestWithSeed(key, signature, digest, nonceRand.data, nonceRand.len);
NSS_DECLASSIFY(signature->data, signature->len);
cleanup:
if (nonceRand.data) {
SECITEM_ZfreeItem(&nonceRand, PR_FALSE);
}
#if EC_DEBUG
printf("ECDSA signing %s\n",
(rv == SECSuccess) ? "succeeded" : "failed");
#endif
return rv;
}
/*
** Checks the signature on the given digest using the key provided.
**
** The key argument must represent a valid EC public key (a point on
** the relevant curve). If it is not a valid point, then the behavior
** of this function is undefined. In cases where a public key might
** not be valid, use EC_ValidatePublicKey to check.
*/
SECStatus
ECDSA_VerifyDigest(ECPublicKey *key, const SECItem *signature,
const SECItem *digest)
{
SECStatus rv = SECFailure;
ECParams *ecParams = NULL;
mp_err err = MP_OKAY;
/* Check args */
if (!key || !signature || !digest) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
rv = SECFailure;
goto done;
}
ecParams = &(key->ecParams);
/* Perform curve specific signature verification using ECMethod */
if (ecParams->fieldID.type == ec_field_plain) {
const ECMethod *method = ec_get_method_from_name(ecParams->name);
if (method == NULL || method->verify_digest == NULL) {
PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE);
rv = SECFailure;
goto done;
}
rv = method->verify_digest(key, signature, digest);
if (rv != SECSuccess) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
}
goto done;
}
mp_int r_, s_; /* tuple (r', s') is received signature) */
mp_int c, u1, u2, v; /* intermediate values used in verification */
mp_int x1;
mp_int n;
SECItem pointC = { siBuffer, NULL, 0 };
int slen; /* length in bytes of a half signature (r or s) */
int flen; /* length in bytes of the field size */
unsigned olen; /* length in bytes of the base point order */
unsigned obits; /* length in bits of the base point order */
#if EC_DEBUG
char mpstr[256];
printf("ECDSA verification called\n");
#endif
/* Initialize MPI integers. */
/* must happen before the first potential call to cleanup */
MP_DIGITS(&r_) = 0;
MP_DIGITS(&s_) = 0;
MP_DIGITS(&c) = 0;
MP_DIGITS(&u1) = 0;
MP_DIGITS(&u2) = 0;
MP_DIGITS(&x1) = 0;
MP_DIGITS(&v) = 0;
MP_DIGITS(&n) = 0;
CHECK_MPI_OK(mp_init(&r_));
CHECK_MPI_OK(mp_init(&s_));
CHECK_MPI_OK(mp_init(&c));
CHECK_MPI_OK(mp_init(&u1));
CHECK_MPI_OK(mp_init(&u2));
CHECK_MPI_OK(mp_init(&x1));
CHECK_MPI_OK(mp_init(&v));
CHECK_MPI_OK(mp_init(&n));
flen = (ecParams->fieldID.size + 7) >> 3;
olen = ecParams->order.len;
if (signature->len == 0 || signature->len % 2 != 0 ||
signature->len > 2 * olen) {
PORT_SetError(SEC_ERROR_INPUT_LEN);
goto cleanup;
}
slen = signature->len / 2;
/*
* The incoming point has been verified in sftk_handlePublicKeyObject.
*/
SECITEM_AllocItem(NULL, &pointC, EC_GetPointSize(ecParams));
if (pointC.data == NULL) {
goto cleanup;
}
/*
** Convert received signature (r', s') into MPI integers.
*/
CHECK_MPI_OK(mp_read_unsigned_octets(&r_, signature->data, slen));
CHECK_MPI_OK(mp_read_unsigned_octets(&s_, signature->data + slen, slen));
/*
** ANSI X9.62, Section 5.4.2, Steps 1 and 2
**
** Verify that 0 < r' < n and 0 < s' < n
*/
SECITEM_TO_MPINT(ecParams->order, &n);
if (mp_cmp_z(&r_) <= 0 || mp_cmp_z(&s_) <= 0 ||
mp_cmp(&r_, &n) >= 0 || mp_cmp(&s_, &n) >= 0) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
goto cleanup; /* will return rv == SECFailure */
}
/*
** ANSI X9.62, Section 5.4.2, Step 3
**
** c = (s')**-1 mod n
*/
CHECK_MPI_OK(mp_invmod(&s_, &n, &c)); /* c = (s')**-1 mod n */
/*
** ANSI X9.62, Section 5.4.2, Step 4
**
** u1 = ((HASH(M')) * c) mod n
*/
SECITEM_TO_MPINT(*digest, &u1); /* u1 = HASH(M) */
/* In the definition of EC signing, digests are truncated
* to the length of n in bits.
* (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
CHECK_MPI_OK((obits = mpl_significant_bits(&n)));
if (digest->len * 8 > obits) { /* u1 = HASH(M') */
mpl_rsh(&u1, &u1, digest->len * 8 - obits);
}
#if EC_DEBUG
mp_todecimal(&r_, mpstr);
printf("r_: %s (dec)\n", mpstr);
mp_todecimal(&s_, mpstr);
printf("s_: %s (dec)\n", mpstr);
mp_todecimal(&c, mpstr);
printf("c : %s (dec)\n", mpstr);
mp_todecimal(&u1, mpstr);
printf("digest: %s (dec)\n", mpstr);
#endif
CHECK_MPI_OK(mp_mulmod(&u1, &c, &n, &u1)); /* u1 = u1 * c mod n */
/*
** ANSI X9.62, Section 5.4.2, Step 4
**
** u2 = ((r') * c) mod n
*/
CHECK_MPI_OK(mp_mulmod(&r_, &c, &n, &u2));
/*
** ANSI X9.62, Section 5.4.3, Step 1
**
** Compute u1*G + u2*Q
** Here, A = u1.G B = u2.Q and C = A + B
** If the result, C, is the point at infinity, reject the signature
*/
if (ec_points_mul(ecParams, &u1, &u2, &key->publicValue, &pointC) != SECSuccess) {
rv = SECFailure;
goto cleanup;
}
if (ec_point_at_infinity(&pointC)) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
rv = SECFailure;
goto cleanup;
}
CHECK_MPI_OK(mp_read_unsigned_octets(&x1, pointC.data + 1, flen));
/*
** ANSI X9.62, Section 5.4.4, Step 2
**
** v = x1 mod n
*/
CHECK_MPI_OK(mp_mod(&x1, &n, &v));
#if EC_DEBUG
mp_todecimal(&r_, mpstr);
printf("r_: %s (dec)\n", mpstr);
mp_todecimal(&v, mpstr);
printf("v : %s (dec)\n", mpstr);
#endif
/*
** ANSI X9.62, Section 5.4.4, Step 3
**
** Verification: v == r'
*/
if (mp_cmp(&v, &r_)) {
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
rv = SECFailure; /* Signature failed to verify. */
} else {
rv = SECSuccess; /* Signature verified. */
}
#if EC_DEBUG
mp_todecimal(&u1, mpstr);
printf("u1: %s (dec)\n", mpstr);
mp_todecimal(&u2, mpstr);
printf("u2: %s (dec)\n", mpstr);
mp_tohex(&x1, mpstr);
printf("x1: %s\n", mpstr);
mp_todecimal(&v, mpstr);
printf("v : %s (dec)\n", mpstr);
#endif
cleanup:
mp_clear(&r_);
mp_clear(&s_);
mp_clear(&c);
mp_clear(&u1);
mp_clear(&u2);
mp_clear(&x1);
mp_clear(&v);
mp_clear(&n);
if (pointC.data)
SECITEM_ZfreeItem(&pointC, PR_FALSE);
done:
if (err) {
MP_TO_SEC_ERROR(err);
rv = SECFailure;
}
#if EC_DEBUG
printf("ECDSA verification %s\n",
(rv == SECSuccess) ? "succeeded" : "failed");
#endif
return rv;
}
/*EdDSA: Currently only Ed22519 is implemented.*/
/*
** Computes the EdDSA signature on the message using the given key.
*/
SECStatus
ec_ED25519_public_key_validate(const ECPublicKey *key)
{
if (!key || !(key->ecParams.name == ECCurve_Ed25519)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
return ec_ED25519_pt_validate(&key->publicValue);
}
SECStatus
ec_ED25519_private_key_validate(const ECPrivateKey *key)
{
if (!key || !(key->ecParams.name == ECCurve_Ed25519)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
return ec_ED25519_scalar_validate(&key->privateValue);
}
SECStatus
ED_SignMessage(ECPrivateKey *key, SECItem *signature, const SECItem *msg)
{
if (!msg || !signature || signature->len != Ed25519_SIGN_LEN) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (ec_ED25519_private_key_validate(key) != SECSuccess) {
return SECFailure; /* error code set by ec_ED25519_scalar_validate. */
}
if (signature->data) {
Hacl_Ed25519_sign(signature->data, key->privateValue.data, msg->len,
msg->data);
}
signature->len = ED25519_SIGN_LEN;
BLAPI_CLEAR_STACK(2048);
return SECSuccess;
}
/*
** Checks the signature on the given message using the key provided.
*/
SECStatus
ED_VerifyMessage(ECPublicKey *key, const SECItem *signature,
const SECItem *msg)
{
if (!msg || !signature || !signature->data || signature->len != Ed25519_SIGN_LEN) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (ec_ED25519_public_key_validate(key) != SECSuccess) {
return SECFailure; /* error code set by ec_ED25519_pt_validate. */
}
bool rv = Hacl_Ed25519_verify(key->publicValue.data, msg->len, msg->data,
signature->data);
BLAPI_CLEAR_STACK(2048);
#if EC_DEBUG
printf("ED_VerifyMessage returning %s\n",
(rv) ? "success" : "failure");
#endif
if (rv) {
return SECSuccess;
}
PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
return SECFailure;
}
SECStatus
ED_DerivePublicKey(const SECItem *privateKey, SECItem *publicKey)
{
/* Currently supporting only Ed25519.*/
if (!privateKey || privateKey->len == 0 || !publicKey || publicKey->len != Ed25519_PUBLIC_KEYLEN) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (ec_ED25519_scalar_validate(privateKey) != SECSuccess) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
Hacl_Ed25519_secret_to_public(publicKey->data, privateKey->data);
return SECSuccess;
}