/* fips/rand/fips_drbg_ec.c */ /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL * project. */ /* ==================================================================== * Copyright (c) 2011 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * licensing@OpenSSL.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== */ #define OPENSSL_FIPSAPI #include #include #include #include #include #include #include "fips_rand_lcl.h" /*#define EC_DRBG_TRACE*/ #ifdef EC_DRBG_TRACE static void hexprint(FILE *out, const unsigned char *buf, int buflen) { int i; fprintf(out, "\t"); for (i = 0; i < buflen; i++) fprintf(out, "%02X", buf[i]); fprintf(out, "\n"); } static void bnprint(FILE *out, const char *name, const BIGNUM *b) { unsigned char *tmp; int len; len = BN_num_bytes(b); tmp = OPENSSL_malloc(len); BN_bn2bin(b, tmp); fprintf(out, "%s\n", name); hexprint(out, tmp, len); OPENSSL_free(tmp); } #if 0 static void ecprint(FILE *out, EC_GROUP *grp, EC_POINT *pt) { BIGNUM *x, *y; x = BN_new(); y = BN_new(); EC_POINT_get_affine_coordinates_GFp(grp, pt, x, y, NULL); bnprint(out, "\tPoint X: ", x); bnprint(out, "\tPoint Y: ", y); BN_free(x); BN_free(y); } #endif #endif /* This is Hash_df from SP 800-90 10.4.1 */ static int hash_df(DRBG_CTX *dctx, unsigned char *out, const unsigned char *in1, size_t in1len, const unsigned char *in2, size_t in2len, const unsigned char *in3, size_t in3len) { DRBG_EC_CTX *ectx = &dctx->d.ec; EVP_MD_CTX *mctx = &ectx->mctx; unsigned char *vtmp = ectx->vtmp; unsigned char tmp[6]; size_t mdlen = M_EVP_MD_size(ectx->md); /* Standard only ever needs seedlen bytes which is always less than * maximum permitted so no need to check length. */ size_t outlen = dctx->seedlen; size_t nbits = (outlen << 3) - ectx->exbits; tmp[0] = 1; tmp[1] = (nbits >> 24) & 0xff; tmp[2] = (nbits >> 16) & 0xff; tmp[3] = (nbits >> 8) & 0xff; tmp[4] = nbits & 0xff; if (!in1) { tmp[5] = (unsigned char)in1len; in1 = tmp + 5; in1len = 1; } for (;;) { if (!FIPS_digestinit(mctx, ectx->md)) return 0; if (!FIPS_digestupdate(mctx, tmp, 5)) return 0; if (in1 && !FIPS_digestupdate(mctx, in1, in1len)) return 0; if (in2 && !FIPS_digestupdate(mctx, in2, in2len)) return 0; if (in3 && !FIPS_digestupdate(mctx, in3, in3len)) return 0; if (outlen < mdlen) { if (!FIPS_digestfinal(mctx, vtmp, NULL)) return 0; memcpy(out, vtmp, outlen); OPENSSL_cleanse(vtmp, mdlen); return 1; } else if(!FIPS_digestfinal(mctx, out, NULL)) return 0; outlen -= mdlen; if (outlen == 0) return 1; tmp[0]++; out += mdlen; } } static int bn2binpad(unsigned char *to, size_t tolen, BIGNUM *b) { size_t blen; blen = BN_num_bytes(b); /* If BIGNUM length greater than buffer, mask to get rightmost * bytes. NB: modifies b but this doesn't matter for our purposes. */ if (blen > tolen) { BN_mask_bits(b, tolen << 3); /* Update length because mask operation might create leading * zeroes. */ blen = BN_num_bytes(b); } /* If b length smaller than buffer pad with zeroes */ if (blen < tolen) { memset(to, 0, tolen - blen); to += tolen - blen; } /* This call cannot fail */ BN_bn2bin(b, to); return 1; } /* Convert buffer to a BIGNUM discarding extra bits if necessary */ static int bin2bnbits(DRBG_CTX *dctx, BIGNUM *r, const unsigned char *buf) { DRBG_EC_CTX *ectx = &dctx->d.ec; if (!BN_bin2bn(buf, dctx->seedlen, r)) return 0; /* If we have extra bits right shift off the end of r */ if (ectx->exbits) { if (!BN_rshift(r, r, ectx->exbits)) return 0; } return 1; } /* Calculate r = phi(s * P) or r= phi(s * Q) */ static int drbg_ec_mul(DRBG_EC_CTX *ectx, BIGNUM *r, const BIGNUM *s, int use_q) { if (use_q) { if (!EC_POINT_mul(ectx->curve, ectx->ptmp, NULL, ectx->Q, s, ectx->bctx)) return 0; } else { if (!EC_POINT_mul(ectx->curve, ectx->ptmp, s, NULL, NULL, ectx->bctx)) return 0; } /* Get x coordinate of result */ if (!EC_POINT_get_affine_coordinates_GFp(ectx->curve, ectx->ptmp, r, NULL, ectx->bctx)) return 0; return 1; } static int drbg_ec_instantiate(DRBG_CTX *dctx, const unsigned char *ent, size_t ent_len, const unsigned char *nonce, size_t nonce_len, const unsigned char *pstr, size_t pstr_len) { DRBG_EC_CTX *ectx = &dctx->d.ec; if (!hash_df(dctx, ectx->sbuf, ent, ent_len, nonce, nonce_len, pstr, pstr_len)) return 0; if (!bin2bnbits(dctx, ectx->s, ectx->sbuf)) return 0; return 1; } static int drbg_ec_reseed(DRBG_CTX *dctx, const unsigned char *ent, size_t ent_len, const unsigned char *adin, size_t adin_len) { DRBG_EC_CTX *ectx = &dctx->d.ec; /* Convert s value to a binary buffer. Save it to tbuf as we are * about to overwrite it. */ if (ectx->exbits) BN_lshift(ectx->s, ectx->s, ectx->exbits); bn2binpad(ectx->tbuf, dctx->seedlen, ectx->s); if (!hash_df(dctx, ectx->sbuf, ectx->tbuf, dctx->seedlen, ent, ent_len, adin, adin_len)) return 0; if (!bin2bnbits(dctx, ectx->s, ectx->sbuf)) return 0; dctx->reseed_counter = 0; return 1; } static int drbg_ec_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen, const unsigned char *adin, size_t adin_len) { DRBG_EC_CTX *ectx = &dctx->d.ec; BIGNUM *t, *r; BIGNUM *s = ectx->s; /* special case: check reseed interval */ if (out == NULL) { size_t nb = (outlen + dctx->blocklength - 1)/dctx->blocklength; if (dctx->reseed_counter + nb > dctx->reseed_interval) dctx->status = DRBG_STATUS_RESEED; return 1; } BN_CTX_start(ectx->bctx); r = BN_CTX_get(ectx->bctx); if (!r) goto err; if (adin && adin_len) { size_t i; t = BN_CTX_get(ectx->bctx); if (!t) goto err; /* Convert s to buffer */ if (ectx->exbits) BN_lshift(s, s, ectx->exbits); bn2binpad(ectx->sbuf, dctx->seedlen, s); /* Step 2 */ if (!hash_df(dctx, ectx->tbuf, adin, adin_len, NULL, 0, NULL, 0)) goto err; /* Step 5 */ for (i = 0; i < dctx->seedlen; i++) ectx->tbuf[i] ^= ectx->sbuf[i]; if (!bin2bnbits(dctx, t, ectx->tbuf)) return 0; } else /* Note if no additional input the algorithm never * needs separate values for t and s. */ t = s; #ifdef EC_DRBG_TRACE bnprint(stderr, "s at start of generate: ", s); #endif for (;;) { /* Step #6, calculate s = t * P */ if (!drbg_ec_mul(ectx, s, t, 0)) goto err; #ifdef EC_DRBG_TRACE bnprint(stderr, "s in generate: ", ectx->s); #endif /* Step #7, calculate r = s * Q */ if (!drbg_ec_mul(ectx, r, s, 1)) goto err; #ifdef EC_DRBG_TRACE bnprint(stderr, "r in generate is: ", r); #endif dctx->reseed_counter++; /* Get rightmost bits of r to output buffer */ if (!(dctx->xflags & DRBG_FLAG_TEST) && !dctx->lb_valid) { if (!bn2binpad(dctx->lb, dctx->blocklength, r)) goto err; dctx->lb_valid = 1; continue; } if (outlen < dctx->blocklength) { if (!bn2binpad(ectx->vtmp, dctx->blocklength, r)) goto err; if (!fips_drbg_cprng_test(dctx, ectx->vtmp)) goto err; memcpy(out, ectx->vtmp, outlen); break; } else { if (!bn2binpad(out, dctx->blocklength, r)) goto err; if (!fips_drbg_cprng_test(dctx, out)) goto err; } outlen -= dctx->blocklength; if (!outlen) break; out += dctx->blocklength; /* Step #5 after first pass */ t = s; #ifdef EC_DRBG_TRACE fprintf(stderr, "Random bits written:\n"); hexprint(stderr, out, dctx->blocklength); #endif } if (!drbg_ec_mul(ectx, ectx->s, ectx->s, 0)) return 0; #ifdef EC_DRBG_TRACE bnprint(stderr, "s after generate is: ", s); #endif BN_CTX_end(ectx->bctx); return 1; err: BN_CTX_end(ectx->bctx); return 0; } static int drbg_ec_uninstantiate(DRBG_CTX *dctx) { DRBG_EC_CTX *ectx = &dctx->d.ec; EVP_MD_CTX_cleanup(&ectx->mctx); EC_GROUP_free(ectx->curve); EC_POINT_free(ectx->Q); EC_POINT_free(ectx->ptmp); BN_clear_free(ectx->s); BN_CTX_free(ectx->bctx); OPENSSL_cleanse(&dctx->d.ec, sizeof(DRBG_EC_CTX)); return 1; } /* Q points from SP 800-90 A.1, P is generator */ __fips_constseg static const unsigned char p_256_qx[] = { 0xc9,0x74,0x45,0xf4,0x5c,0xde,0xf9,0xf0,0xd3,0xe0,0x5e,0x1e, 0x58,0x5f,0xc2,0x97,0x23,0x5b,0x82,0xb5,0xbe,0x8f,0xf3,0xef, 0xca,0x67,0xc5,0x98,0x52,0x01,0x81,0x92 }; __fips_constseg static const unsigned char p_256_qy[] = { 0xb2,0x8e,0xf5,0x57,0xba,0x31,0xdf,0xcb,0xdd,0x21,0xac,0x46, 0xe2,0xa9,0x1e,0x3c,0x30,0x4f,0x44,0xcb,0x87,0x05,0x8a,0xda, 0x2c,0xb8,0x15,0x15,0x1e,0x61,0x00,0x46 }; __fips_constseg static const unsigned char p_384_qx[] = { 0x8e,0x72,0x2d,0xe3,0x12,0x5b,0xdd,0xb0,0x55,0x80,0x16,0x4b, 0xfe,0x20,0xb8,0xb4,0x32,0x21,0x6a,0x62,0x92,0x6c,0x57,0x50, 0x2c,0xee,0xde,0x31,0xc4,0x78,0x16,0xed,0xd1,0xe8,0x97,0x69, 0x12,0x41,0x79,0xd0,0xb6,0x95,0x10,0x64,0x28,0x81,0x50,0x65 }; __fips_constseg static const unsigned char p_384_qy[] = { 0x02,0x3b,0x16,0x60,0xdd,0x70,0x1d,0x08,0x39,0xfd,0x45,0xee, 0xc3,0x6f,0x9e,0xe7,0xb3,0x2e,0x13,0xb3,0x15,0xdc,0x02,0x61, 0x0a,0xa1,0xb6,0x36,0xe3,0x46,0xdf,0x67,0x1f,0x79,0x0f,0x84, 0xc5,0xe0,0x9b,0x05,0x67,0x4d,0xbb,0x7e,0x45,0xc8,0x03,0xdd }; __fips_constseg static const unsigned char p_521_qx[] = { 0x01,0xb9,0xfa,0x3e,0x51,0x8d,0x68,0x3c,0x6b,0x65,0x76,0x36, 0x94,0xac,0x8e,0xfb,0xae,0xc6,0xfa,0xb4,0x4f,0x22,0x76,0x17, 0x1a,0x42,0x72,0x65,0x07,0xdd,0x08,0xad,0xd4,0xc3,0xb3,0xf4, 0xc1,0xeb,0xc5,0xb1,0x22,0x2d,0xdb,0xa0,0x77,0xf7,0x22,0x94, 0x3b,0x24,0xc3,0xed,0xfa,0x0f,0x85,0xfe,0x24,0xd0,0xc8,0xc0, 0x15,0x91,0xf0,0xbe,0x6f,0x63 }; __fips_constseg static const unsigned char p_521_qy[] = { 0x01,0xf3,0xbd,0xba,0x58,0x52,0x95,0xd9,0xa1,0x11,0x0d,0x1d, 0xf1,0xf9,0x43,0x0e,0xf8,0x44,0x2c,0x50,0x18,0x97,0x6f,0xf3, 0x43,0x7e,0xf9,0x1b,0x81,0xdc,0x0b,0x81,0x32,0xc8,0xd5,0xc3, 0x9c,0x32,0xd0,0xe0,0x04,0xa3,0x09,0x2b,0x7d,0x32,0x7c,0x0e, 0x7a,0x4d,0x26,0xd2,0xc7,0xb6,0x9b,0x58,0xf9,0x06,0x66,0x52, 0x91,0x1e,0x45,0x77,0x79,0xde }; int fips_drbg_ec_init(DRBG_CTX *dctx) { const EVP_MD *md; const unsigned char *Q_x, *Q_y; BIGNUM *x, *y; size_t ptlen; int md_nid = dctx->type & 0xffff; int curve_nid = dctx->type >> 16; DRBG_EC_CTX *ectx = &dctx->d.ec; md = FIPS_get_digestbynid(md_nid); if (!md) return -2; /* These are taken from SP 800-90 10.3.1 table 4 */ switch (curve_nid) { case NID_X9_62_prime256v1: dctx->strength = 128; dctx->seedlen = 32; dctx->blocklength = 30; ectx->exbits = 0; Q_x = p_256_qx; Q_y = p_256_qy; ptlen = sizeof(p_256_qx); break; case NID_secp384r1: if (md_nid == NID_sha1) return -2; dctx->strength = 192; dctx->seedlen = 48; dctx->blocklength = 46; ectx->exbits = 0; Q_x = p_384_qx; Q_y = p_384_qy; ptlen = sizeof(p_384_qx); break; case NID_secp521r1: if (md_nid == NID_sha1 || md_nid == NID_sha224) return -2; dctx->strength = 256; dctx->seedlen = 66; dctx->blocklength = 63; ectx->exbits = 7; Q_x = p_521_qx; Q_y = p_521_qy; ptlen = sizeof(p_521_qx); break; default: return -2; } dctx->iflags |= DRBG_CUSTOM_RESEED; dctx->reseed_counter = 0; dctx->instantiate = drbg_ec_instantiate; dctx->reseed = drbg_ec_reseed; dctx->generate = drbg_ec_generate; dctx->uninstantiate = drbg_ec_uninstantiate; ectx->md = md; EVP_MD_CTX_init(&ectx->mctx); dctx->min_entropy = dctx->strength / 8; dctx->max_entropy = 2 << 10; dctx->min_nonce = dctx->min_entropy / 2; dctx->max_nonce = 2 << 10; dctx->max_pers = 2 << 10; dctx->max_adin = 2 << 10; dctx->reseed_interval = 1<<24; dctx->max_request = dctx->reseed_interval * dctx->blocklength; /* Setup internal structures */ ectx->bctx = BN_CTX_new(); if (!ectx->bctx) return 0; BN_CTX_start(ectx->bctx); ectx->s = BN_new(); ectx->curve = EC_GROUP_new_by_curve_name(curve_nid); ectx->Q = EC_POINT_new(ectx->curve); ectx->ptmp = EC_POINT_new(ectx->curve); x = BN_CTX_get(ectx->bctx); y = BN_CTX_get(ectx->bctx); if (!ectx->s || !ectx->curve || !ectx->Q || !y) goto err; if (!BN_bin2bn(Q_x, ptlen, x) || !BN_bin2bn(Q_y, ptlen, y)) goto err; if (!EC_POINT_set_affine_coordinates_GFp(ectx->curve, ectx->Q, x, y, ectx->bctx)) goto err; BN_CTX_end(ectx->bctx); return 1; err: BN_CTX_end(ectx->bctx); drbg_ec_uninstantiate(dctx); return 0; }