ecdecode.c (8886B)
1 /* This Source Code Form is subject to the terms of the Mozilla Public 2 * License, v. 2.0. If a copy of the MPL was not distributed with this 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 4 5 #ifdef FREEBL_NO_DEPEND 6 #include "stubs.h" 7 #endif 8 9 #include "blapi.h" 10 #include "secoid.h" 11 #include "secitem.h" 12 #include "secerr.h" 13 #include "ec.h" 14 #include "ecl-curve.h" 15 16 #define CHECK_OK(func) \ 17 if (func == NULL) \ 18 goto cleanup 19 #define CHECK_SEC_OK(func) \ 20 if (SECSuccess != (rv = func)) \ 21 goto cleanup 22 23 /* Copy all of the fields from srcParams into dstParams 24 */ 25 SECStatus 26 EC_CopyParams(PLArenaPool *arena, ECParams *dstParams, 27 const ECParams *srcParams) 28 { 29 SECStatus rv = SECFailure; 30 31 dstParams->arena = arena; 32 dstParams->type = srcParams->type; 33 dstParams->fieldID.size = srcParams->fieldID.size; 34 dstParams->fieldID.type = srcParams->fieldID.type; 35 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->fieldID.u.prime, 36 &srcParams->fieldID.u.prime)); 37 dstParams->fieldID.k1 = srcParams->fieldID.k1; 38 dstParams->fieldID.k2 = srcParams->fieldID.k2; 39 dstParams->fieldID.k3 = srcParams->fieldID.k3; 40 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->curve.a, 41 &srcParams->curve.a)); 42 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->curve.b, 43 &srcParams->curve.b)); 44 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->curve.seed, 45 &srcParams->curve.seed)); 46 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->base, 47 &srcParams->base)); 48 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->order, 49 &srcParams->order)); 50 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->DEREncoding, 51 &srcParams->DEREncoding)); 52 dstParams->name = srcParams->name; 53 CHECK_SEC_OK(SECITEM_CopyItem(arena, &dstParams->curveOID, 54 &srcParams->curveOID)); 55 dstParams->cofactor = srcParams->cofactor; 56 57 return SECSuccess; 58 59 cleanup: 60 return SECFailure; 61 } 62 63 static SECStatus 64 gf_populate_params_bytes(ECCurveName name, ECFieldType field_type, ECParams *params) 65 { 66 SECStatus rv = SECFailure; 67 const ECCurveBytes *curveParams; 68 69 if ((name < ECCurve_noName) || (name > ECCurve_pastLastCurve)) 70 goto cleanup; 71 params->name = name; 72 curveParams = ecCurve_map[params->name]; 73 CHECK_OK(curveParams); 74 params->fieldID.size = curveParams->size; 75 params->fieldID.type = field_type; 76 if (field_type != ec_field_plain) { 77 return SECFailure; 78 } 79 params->fieldID.u.prime.len = curveParams->scalarSize; 80 params->fieldID.u.prime.data = (unsigned char *)curveParams->irr; 81 params->curve.a.len = curveParams->scalarSize; 82 params->curve.a.data = (unsigned char *)curveParams->curvea; 83 params->curve.b.len = curveParams->scalarSize; 84 params->curve.b.data = (unsigned char *)curveParams->curveb; 85 params->base.len = curveParams->pointSize; 86 params->base.data = (unsigned char *)curveParams->base; 87 params->order.len = curveParams->scalarSize; 88 params->order.data = (unsigned char *)curveParams->order; 89 params->cofactor = curveParams->cofactor; 90 91 rv = SECSuccess; 92 93 cleanup: 94 return rv; 95 } 96 97 SECStatus 98 EC_FillParams(PLArenaPool *arena, const SECItem *encodedParams, 99 ECParams *params) 100 { 101 SECStatus rv = SECFailure; 102 SECOidTag tag; 103 SECItem oid = { siBuffer, NULL, 0 }; 104 105 #if EC_DEBUG 106 int i; 107 108 printf("Encoded params in EC_DecodeParams: "); 109 for (i = 0; i < encodedParams->len; i++) { 110 printf("%02x:", encodedParams->data[i]); 111 } 112 printf("\n"); 113 #endif 114 115 if ((encodedParams->len != ANSI_X962_CURVE_OID_TOTAL_LEN) && 116 (encodedParams->len != SECG_CURVE_OID_TOTAL_LEN) && 117 (encodedParams->len != PKIX_NEWCURVES_OID_TOTAL_LEN) && 118 (encodedParams->len != ED25519_OID_TOTAL_LEN)) { 119 PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE); 120 return SECFailure; 121 }; 122 123 oid.len = encodedParams->len - 2; 124 oid.data = encodedParams->data + 2; 125 if ((encodedParams->data[0] != SEC_ASN1_OBJECT_ID) || 126 ((tag = SECOID_FindOIDTag(&oid)) == SEC_OID_UNKNOWN)) { 127 PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE); 128 return SECFailure; 129 } 130 131 params->arena = arena; 132 params->cofactor = 0; 133 params->type = ec_params_named; 134 params->name = ECCurve_noName; 135 136 /* Fill out curveOID */ 137 params->curveOID.len = oid.len; 138 params->curveOID.data = (unsigned char *)PORT_ArenaAlloc(arena, oid.len); 139 if (params->curveOID.data == NULL) 140 goto cleanup; 141 memcpy(params->curveOID.data, oid.data, oid.len); 142 143 #if EC_DEBUG 144 printf("Curve: %s\n", SECOID_FindOIDTagDescription(tag)); 145 #endif 146 147 switch (tag) { 148 case SEC_OID_ANSIX962_EC_PRIME256V1: 149 /* Populate params for prime256v1 aka secp256r1 150 * (the NIST P-256 curve) 151 */ 152 CHECK_SEC_OK(gf_populate_params_bytes(ECCurve_X9_62_PRIME_256V1, 153 ec_field_plain, params)); 154 break; 155 156 case SEC_OID_SECG_EC_SECP384R1: 157 /* Populate params for secp384r1 158 * (the NIST P-384 curve) 159 */ 160 CHECK_SEC_OK(gf_populate_params_bytes(ECCurve_SECG_PRIME_384R1, 161 ec_field_plain, params)); 162 break; 163 164 case SEC_OID_SECG_EC_SECP521R1: 165 /* Populate params for secp521r1 166 * (the NIST P-521 curve) 167 */ 168 CHECK_SEC_OK(gf_populate_params_bytes(ECCurve_SECG_PRIME_521R1, 169 ec_field_plain, params)); 170 break; 171 172 case SEC_OID_ED25519_PUBLIC_KEY: 173 params->type = ec_params_edwards_named; 174 CHECK_SEC_OK(gf_populate_params_bytes(ECCurve_Ed25519, 175 ec_field_plain, params)); 176 177 break; 178 179 case SEC_OID_X25519: 180 case SEC_OID_CURVE25519: 181 /* Populate params for Curve25519 */ 182 params->type = ec_params_montgomery_named; 183 CHECK_SEC_OK(gf_populate_params_bytes(ECCurve25519, 184 ec_field_plain, 185 params)); 186 break; 187 188 default: 189 break; 190 }; 191 192 cleanup: 193 if (!params->cofactor) { 194 PORT_SetError(SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE); 195 #if EC_DEBUG 196 printf("Unrecognized curve, returning NULL params\n"); 197 #endif 198 } 199 200 return rv; 201 } 202 203 SECStatus 204 EC_DecodeParams(const SECItem *encodedParams, ECParams **ecparams) 205 { 206 PLArenaPool *arena; 207 ECParams *params; 208 SECStatus rv = SECFailure; 209 210 /* Initialize an arena for the ECParams structure */ 211 if (!(arena = PORT_NewArena(NSS_FREEBL_DEFAULT_CHUNKSIZE))) 212 return SECFailure; 213 214 params = (ECParams *)PORT_ArenaZAlloc(arena, sizeof(ECParams)); 215 if (!params) { 216 PORT_FreeArena(arena, PR_TRUE); 217 return SECFailure; 218 } 219 220 /* Copy the encoded params */ 221 SECITEM_AllocItem(arena, &(params->DEREncoding), 222 encodedParams->len); 223 memcpy(params->DEREncoding.data, encodedParams->data, encodedParams->len); 224 225 /* Fill out the rest of the ECParams structure based on 226 * the encoded params 227 */ 228 rv = EC_FillParams(arena, encodedParams, params); 229 if (rv == SECFailure) { 230 PORT_FreeArena(arena, PR_TRUE); 231 return SECFailure; 232 } else { 233 *ecparams = params; 234 ; 235 return SECSuccess; 236 } 237 } 238 239 int 240 EC_GetPointSize(const ECParams *params) 241 { 242 ECCurveName name = params->name; 243 const ECCurveBytes *curveParams; 244 245 if ((name < ECCurve_noName) || (name > ECCurve_pastLastCurve) || 246 ((curveParams = ecCurve_map[name]) == NULL)) { 247 /* unknown curve, calculate point size from params. assume standard curves with 2 points 248 * and a point compression indicator byte */ 249 int sizeInBytes = (params->fieldID.size + 7) / 8; 250 return sizeInBytes * 2 + 1; 251 } 252 253 if (params->type == ec_params_edwards_named || params->type == ec_params_montgomery_named) { 254 return curveParams->scalarSize; 255 } 256 257 return curveParams->pointSize - 1; 258 } 259 260 int 261 EC_GetScalarSize(const ECParams *params) 262 { 263 ECCurveName name = params->name; 264 const ECCurveBytes *curveParams; 265 266 if ((name < ECCurve_noName) || (name > ECCurve_pastLastCurve) || 267 ((curveParams = ecCurve_map[name]) == NULL)) { 268 /* unknown curve, calculate scalar size from field size in params */ 269 int sizeInBytes = (params->fieldID.size + 7) / 8; 270 return sizeInBytes; 271 } 272 return curveParams->scalarSize; 273 }