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-rw-r--r--security/nss/lib/freebl/ec.c1159
1 files changed, 1159 insertions, 0 deletions
diff --git a/security/nss/lib/freebl/ec.c b/security/nss/lib/freebl/ec.c
new file mode 100644
index 000000000..12bfeed41
--- /dev/null
+++ b/security/nss/lib/freebl/ec.c
@@ -0,0 +1,1159 @@
+/* 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 "prerr.h"
+#include "secerr.h"
+#include "secmpi.h"
+#include "secitem.h"
+#include "mplogic.h"
+#include "ec.h"
+#include "ecl.h"
+
+#ifndef NSS_DISABLE_ECC
+
+static const ECMethod kMethods[] = {
+ { ECCurve25519,
+ ec_Curve25519_pt_mul,
+ ec_Curve25519_pt_validate }
+};
+
+static const ECMethod *
+ec_get_method_from_name(ECCurveName name)
+{
+ int 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;
+ 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 = (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));
+ }
+
+ /* 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;
+}
+#endif /* NSS_DISABLE_ECC */
+
+/* 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;
+#ifndef NSS_DISABLE_ECC
+ 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 || !privKey || !privKeyBytes || (privKeyLen < 0) ||
+ !ecParams->name) {
+ 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->fieldID.type == ec_field_plain) {
+ const ECMethod *method = ec_get_method_from_name(ecParams->name);
+ if (method == NULL || method->mul == NULL) {
+ /* unknown curve */
+ rv = SECFailure;
+ goto cleanup;
+ }
+ rv = method->mul(&key->publicValue, &key->privateValue, NULL);
+ 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));
+ 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
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+ 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;
+#ifndef NSS_DISABLE_ECC
+ rv = ec_NewKey(ecParams, privKey, seed, seedlen);
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+ return rv;
+}
+
+#ifndef NSS_DISABLE_ECC
+/* Generate a random private key using the algorithm A.4.1 of ANSI X9.62,
+ * modified a la FIPS 186-2 Change Notice 1 to eliminate the bias in the
+ * random number generator.
+ *
+ * Parameters
+ * - order: a buffer that holds the curve's group order
+ * - len: the length in octets of the order buffer
+ *
+ * Return Value
+ * Returns a buffer of len octets that holds the private key. The caller
+ * is responsible for freeing the buffer with PORT_ZFree.
+ */
+static unsigned char *
+ec_GenerateRandomPrivateKey(const unsigned char *order, int len)
+{
+ SECStatus rv = SECSuccess;
+ mp_err err;
+ unsigned char *privKeyBytes = NULL;
+ mp_int privKeyVal, order_1, one;
+
+ MP_DIGITS(&privKeyVal) = 0;
+ MP_DIGITS(&order_1) = 0;
+ MP_DIGITS(&one) = 0;
+ CHECK_MPI_OK(mp_init(&privKeyVal));
+ CHECK_MPI_OK(mp_init(&order_1));
+ CHECK_MPI_OK(mp_init(&one));
+
+ /* Generates 2*len random bytes using the global random bit generator
+ * (which implements Algorithm 1 of FIPS 186-2 Change Notice 1) then
+ * reduces modulo the group order.
+ */
+ if ((privKeyBytes = PORT_Alloc(2 * len)) == NULL)
+ goto cleanup;
+ CHECK_SEC_OK(RNG_GenerateGlobalRandomBytes(privKeyBytes, 2 * len));
+ CHECK_MPI_OK(mp_read_unsigned_octets(&privKeyVal, privKeyBytes, 2 * len));
+ CHECK_MPI_OK(mp_read_unsigned_octets(&order_1, order, len));
+ CHECK_MPI_OK(mp_set_int(&one, 1));
+ CHECK_MPI_OK(mp_sub(&order_1, &one, &order_1));
+ CHECK_MPI_OK(mp_mod(&privKeyVal, &order_1, &privKeyVal));
+ CHECK_MPI_OK(mp_add(&privKeyVal, &one, &privKeyVal));
+ CHECK_MPI_OK(mp_to_fixlen_octets(&privKeyVal, privKeyBytes, len));
+ memset(privKeyBytes + len, 0, len);
+cleanup:
+ mp_clear(&privKeyVal);
+ mp_clear(&order_1);
+ mp_clear(&one);
+ if (err < MP_OKAY) {
+ MP_TO_SEC_ERROR(err);
+ rv = SECFailure;
+ }
+ if (rv != SECSuccess && privKeyBytes) {
+ PORT_ZFree(privKeyBytes, 2 * len);
+ privKeyBytes = NULL;
+ }
+ return privKeyBytes;
+}
+#endif /* NSS_DISABLE_ECC */
+
+/* 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;
+#ifndef NSS_DISABLE_ECC
+ int len;
+ unsigned char *privKeyBytes = NULL;
+
+ if (!ecParams) {
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ return SECFailure;
+ }
+
+ len = ecParams->order.len;
+ privKeyBytes = ec_GenerateRandomPrivateKey(ecParams->order.data, len);
+ if (privKeyBytes == NULL)
+ goto cleanup;
+ /* generate public key */
+ CHECK_SEC_OK(ec_NewKey(ecParams, privKey, privKeyBytes, len));
+
+cleanup:
+ if (privKeyBytes) {
+ PORT_ZFree(privKeyBytes, len);
+ }
+#if EC_DEBUG
+ printf("EC_NewKey returning %s\n",
+ (rv == SECSuccess) ? "success" : "failure");
+#endif
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+ 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)
+{
+#ifndef NSS_DISABLE_ECC
+ mp_int Px, Py;
+ ECGroup *group = NULL;
+ SECStatus rv = SECFailure;
+ mp_err err = MP_OKAY;
+ int len;
+
+ if (!ecParams || !publicValue || !ecParams->name) {
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ return SECFailure;
+ }
+
+ /* 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->validate == NULL) {
+ /* unknown curve */
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ return SECFailure;
+ }
+ return method->validate(publicValue);
+ }
+
+ /* NOTE: We only support uncompressed points for now */
+ len = (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;
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+ return SECFailure;
+#endif /* NSS_DISABLE_ECC */
+}
+
+/*
+** 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;
+#ifndef NSS_DISABLE_ECC
+ unsigned int len = 0;
+ SECItem pointQ = { siBuffer, NULL, 0 };
+ mp_int k; /* to hold the private value */
+ mp_int cofactor;
+ mp_err err = MP_OKAY;
+#if EC_DEBUG
+ int i;
+#endif
+
+ if (!publicValue || !ecParams || !privateValue || !derivedSecret ||
+ !ecParams->name) {
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ return SECFailure;
+ }
+
+ /* 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_GetPointSize(ecParams));
+ if (derivedSecret == NULL) {
+ PORT_SetError(SEC_ERROR_NO_MEMORY);
+ return SECFailure;
+ }
+ method = ec_get_method_from_name(ecParams->name);
+ if (method == NULL || method->validate == NULL ||
+ method->mul == NULL) {
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE);
+ return SECFailure;
+ }
+ if (method->validate(publicValue) != SECSuccess) {
+ PORT_SetError(SEC_ERROR_BAD_KEY);
+ return SECFailure;
+ }
+ return method->mul(derivedSecret, privateValue, publicValue);
+ }
+
+ /*
+ * 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)) {
+ /* 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));
+ }
+
+ /* 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 (err) {
+ MP_TO_SEC_ERROR(err);
+ }
+
+ if (pointQ.data) {
+ PORT_ZFree(pointQ.data, pointQ.len);
+ }
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+ 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).
+ */
+SECStatus
+ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature,
+ const SECItem *digest, const unsigned char *kb, const int kblen)
+{
+ SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+ 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_err err = MP_OKAY;
+ ECParams *ecParams = NULL;
+ SECItem kGpoint = { siBuffer, NULL, 0 };
+ int flen = 0; /* 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 */
+ unsigned char *t2 = NULL;
+
+#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;
+
+ /* Check args */
+ if (!key || !signature || !digest || !kb || (kblen < 0)) {
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ goto cleanup;
+ }
+
+ 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 */
+ goto finish;
+ }
+ if (signature->len < 2 * olen) {
+ PORT_SetError(SEC_ERROR_OUTPUT_LEN);
+ goto cleanup;
+ }
+
+ 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));
+
+ 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;
+ }
+
+ /*
+ ** We do not want timing information to leak the length of k,
+ ** so we compute k*G using an equivalent scalar of fixed
+ ** bit-length.
+ ** Fix based on patch for ECDSA timing attack in the paper
+ ** by Billy Bob Brumley and Nicola Tuveri at
+ ** http://eprint.iacr.org/2011/232
+ **
+ ** How do we convert k to a value of a fixed bit-length?
+ ** k starts off as an integer satisfying 0 <= k < n. Hence,
+ ** n <= k+n < 2n, which means k+n has either the same number
+ ** of bits as n or one more bit than n. If k+n has the same
+ ** number of bits as n, the second addition ensures that the
+ ** final value has exactly one more bit than n. Thus, we
+ ** always end up with a value that exactly one more bit than n.
+ */
+ CHECK_MPI_OK(mp_add(&k, &n, &k));
+ if (mpl_significant_bits(&k) <= mpl_significant_bits(&n)) {
+ CHECK_MPI_OK(mp_add(&k, &n, &k));
+ }
+
+ /*
+ ** 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;
+
+ /*
+ ** 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 */
+ 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 */
+ CHECK_MPI_OK(mp_mulmod(&d, &r, &n, &d)); /* d = d * r mod n */
+ CHECK_MPI_OK(mp_addmod(&s, &d, &n, &s)); /* s = s + d mod n */
+ 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));
+finish:
+ 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);
+
+ if (t2) {
+ PORT_Free(t2);
+ }
+
+ if (kGpoint.data) {
+ PORT_ZFree(kGpoint.data, kGpoint.len);
+ }
+
+ if (err) {
+ MP_TO_SEC_ERROR(err);
+ rv = SECFailure;
+ }
+
+#if EC_DEBUG
+ printf("ECDSA signing with seed %s\n",
+ (rv == SECSuccess) ? "succeeded" : "failed");
+#endif
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+ return rv;
+}
+
+/*
+** 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;
+#ifndef NSS_DISABLE_ECC
+ int len;
+ unsigned char *kBytes = NULL;
+
+ if (!key) {
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ return SECFailure;
+ }
+
+ /* Generate random value k */
+ len = key->ecParams.order.len;
+ kBytes = ec_GenerateRandomPrivateKey(key->ecParams.order.data, len);
+ if (kBytes == NULL)
+ goto cleanup;
+
+ /* Generate ECDSA signature with the specified k value */
+ rv = ECDSA_SignDigestWithSeed(key, signature, digest, kBytes, len);
+
+cleanup:
+ if (kBytes) {
+ PORT_ZFree(kBytes, len);
+ }
+
+#if EC_DEBUG
+ printf("ECDSA signing %s\n",
+ (rv == SECSuccess) ? "succeeded" : "failed");
+#endif
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+ 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;
+#ifndef NSS_DISABLE_ECC
+ 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;
+ mp_err err = MP_OKAY;
+ ECParams *ecParams = NULL;
+ 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 args */
+ if (!key || !signature || !digest) {
+ PORT_SetError(SEC_ERROR_INVALID_ARGS);
+ goto cleanup;
+ }
+
+ ecParams = &(key->ecParams);
+ 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;
+
+ SECITEM_AllocItem(NULL, &pointC, EC_GetPointSize(ecParams));
+ if (pointC.data == NULL)
+ goto cleanup;
+
+ 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));
+
+ /*
+ ** 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);
+ if (err) {
+ MP_TO_SEC_ERROR(err);
+ rv = SECFailure;
+ }
+
+#if EC_DEBUG
+ printf("ECDSA verification %s\n",
+ (rv == SECSuccess) ? "succeeded" : "failed");
+#endif
+#else
+ PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+ return rv;
+}