|
- /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
- * All rights reserved.
- *
- * This package is an SSL implementation written
- * by Eric Young (eay@cryptsoft.com).
- * The implementation was written so as to conform with Netscapes SSL.
- *
- * This library is free for commercial and non-commercial use as long as
- * the following conditions are aheared to. The following conditions
- * apply to all code found in this distribution, be it the RC4, RSA,
- * lhash, DES, etc., code; not just the SSL code. The SSL documentation
- * included with this distribution is covered by the same copyright terms
- * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- *
- * Copyright remains Eric Young's, and as such any Copyright notices in
- * the code are not to be removed.
- * If this package is used in a product, Eric Young should be given attribution
- * as the author of the parts of the library used.
- * This can be in the form of a textual message at program startup or
- * in documentation (online or textual) provided with the package.
- *
- * 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 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 acknowledgement:
- * "This product includes cryptographic software written by
- * Eric Young (eay@cryptsoft.com)"
- * The word 'cryptographic' can be left out if the rouines from the library
- * being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from
- * the apps directory (application code) you must include an acknowledgement:
- * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- *
- * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
- * ANY EXPRESS 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 AUTHOR OR 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.
- *
- * The licence and distribution terms for any publically available version or
- * derivative of this code cannot be changed. i.e. this code cannot simply be
- * copied and put under another distribution licence
- * [including the GNU Public Licence.]
- *
- * The DSS routines are based on patches supplied by
- * Steven Schoch <schoch@sheba.arc.nasa.gov>. */
-
- #include <openssl/dsa.h>
-
- #include <string.h>
-
- #include <openssl/bn.h>
- #include <openssl/dh.h>
- #include <openssl/digest.h>
- #include <openssl/engine.h>
- #include <openssl/err.h>
- #include <openssl/ex_data.h>
- #include <openssl/mem.h>
- #include <openssl/rand.h>
- #include <openssl/sha.h>
- #include <openssl/thread.h>
-
- #include "../fipsmodule/bn/internal.h"
- #include "../internal.h"
-
-
- #define OPENSSL_DSA_MAX_MODULUS_BITS 10000
-
- // Primality test according to FIPS PUB 186[-1], Appendix 2.1: 50 rounds of
- // Rabin-Miller
- #define DSS_prime_checks 50
-
- static int dsa_sign_setup(const DSA *dsa, BN_CTX *ctx_in, BIGNUM **out_kinv,
- BIGNUM **out_r);
-
- static CRYPTO_EX_DATA_CLASS g_ex_data_class = CRYPTO_EX_DATA_CLASS_INIT;
-
- DSA *DSA_new(void) {
- DSA *dsa = OPENSSL_malloc(sizeof(DSA));
- if (dsa == NULL) {
- OPENSSL_PUT_ERROR(DSA, ERR_R_MALLOC_FAILURE);
- return NULL;
- }
-
- OPENSSL_memset(dsa, 0, sizeof(DSA));
-
- dsa->references = 1;
-
- CRYPTO_MUTEX_init(&dsa->method_mont_lock);
- CRYPTO_new_ex_data(&dsa->ex_data);
-
- return dsa;
- }
-
- void DSA_free(DSA *dsa) {
- if (dsa == NULL) {
- return;
- }
-
- if (!CRYPTO_refcount_dec_and_test_zero(&dsa->references)) {
- return;
- }
-
- CRYPTO_free_ex_data(&g_ex_data_class, dsa, &dsa->ex_data);
-
- BN_clear_free(dsa->p);
- BN_clear_free(dsa->q);
- BN_clear_free(dsa->g);
- BN_clear_free(dsa->pub_key);
- BN_clear_free(dsa->priv_key);
- BN_MONT_CTX_free(dsa->method_mont_p);
- BN_MONT_CTX_free(dsa->method_mont_q);
- CRYPTO_MUTEX_cleanup(&dsa->method_mont_lock);
- OPENSSL_free(dsa);
- }
-
- int DSA_up_ref(DSA *dsa) {
- CRYPTO_refcount_inc(&dsa->references);
- return 1;
- }
-
- void DSA_get0_key(const DSA *dsa, const BIGNUM **out_pub_key,
- const BIGNUM **out_priv_key) {
- if (out_pub_key != NULL) {
- *out_pub_key = dsa->pub_key;
- }
- if (out_priv_key != NULL) {
- *out_priv_key = dsa->priv_key;
- }
- }
-
- void DSA_get0_pqg(const DSA *dsa, const BIGNUM **out_p, const BIGNUM **out_q,
- const BIGNUM **out_g) {
- if (out_p != NULL) {
- *out_p = dsa->p;
- }
- if (out_q != NULL) {
- *out_q = dsa->q;
- }
- if (out_g != NULL) {
- *out_g = dsa->g;
- }
- }
-
- int DSA_set0_key(DSA *dsa, BIGNUM *pub_key, BIGNUM *priv_key) {
- if (dsa->pub_key == NULL && pub_key == NULL) {
- return 0;
- }
-
- if (pub_key != NULL) {
- BN_free(dsa->pub_key);
- dsa->pub_key = pub_key;
- }
- if (priv_key != NULL) {
- BN_free(dsa->priv_key);
- dsa->priv_key = priv_key;
- }
-
- return 1;
- }
-
- int DSA_set0_pqg(DSA *dsa, BIGNUM *p, BIGNUM *q, BIGNUM *g) {
- if ((dsa->p == NULL && p == NULL) ||
- (dsa->q == NULL && q == NULL) ||
- (dsa->g == NULL && g == NULL)) {
- return 0;
- }
-
- if (p != NULL) {
- BN_free(dsa->p);
- dsa->p = p;
- }
- if (q != NULL) {
- BN_free(dsa->q);
- dsa->q = q;
- }
- if (g != NULL) {
- BN_free(dsa->g);
- dsa->g = g;
- }
-
- return 1;
- }
-
- int DSA_generate_parameters_ex(DSA *dsa, unsigned bits, const uint8_t *seed_in,
- size_t seed_len, int *out_counter,
- unsigned long *out_h, BN_GENCB *cb) {
- int ok = 0;
- unsigned char seed[SHA256_DIGEST_LENGTH];
- unsigned char md[SHA256_DIGEST_LENGTH];
- unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
- BIGNUM *r0, *W, *X, *c, *test;
- BIGNUM *g = NULL, *q = NULL, *p = NULL;
- BN_MONT_CTX *mont = NULL;
- int k, n = 0, m = 0;
- unsigned i;
- int counter = 0;
- int r = 0;
- BN_CTX *ctx = NULL;
- unsigned int h = 2;
- unsigned qsize;
- const EVP_MD *evpmd;
-
- evpmd = (bits >= 2048) ? EVP_sha256() : EVP_sha1();
- qsize = EVP_MD_size(evpmd);
-
- if (bits < 512) {
- bits = 512;
- }
-
- bits = (bits + 63) / 64 * 64;
-
- if (seed_in != NULL) {
- if (seed_len < (size_t)qsize) {
- return 0;
- }
- if (seed_len > (size_t)qsize) {
- // Only consume as much seed as is expected.
- seed_len = qsize;
- }
- OPENSSL_memcpy(seed, seed_in, seed_len);
- }
-
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
- BN_CTX_start(ctx);
-
- r0 = BN_CTX_get(ctx);
- g = BN_CTX_get(ctx);
- W = BN_CTX_get(ctx);
- q = BN_CTX_get(ctx);
- X = BN_CTX_get(ctx);
- c = BN_CTX_get(ctx);
- p = BN_CTX_get(ctx);
- test = BN_CTX_get(ctx);
-
- if (test == NULL || !BN_lshift(test, BN_value_one(), bits - 1)) {
- goto err;
- }
-
- for (;;) {
- // Find q.
- for (;;) {
- // step 1
- if (!BN_GENCB_call(cb, 0, m++)) {
- goto err;
- }
-
- int use_random_seed = (seed_in == NULL);
- if (use_random_seed) {
- if (!RAND_bytes(seed, qsize)) {
- goto err;
- }
- } else {
- // If we come back through, use random seed next time.
- seed_in = NULL;
- }
- OPENSSL_memcpy(buf, seed, qsize);
- OPENSSL_memcpy(buf2, seed, qsize);
- // precompute "SEED + 1" for step 7:
- for (i = qsize - 1; i < qsize; i--) {
- buf[i]++;
- if (buf[i] != 0) {
- break;
- }
- }
-
- // step 2
- if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL) ||
- !EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL)) {
- goto err;
- }
- for (i = 0; i < qsize; i++) {
- md[i] ^= buf2[i];
- }
-
- // step 3
- md[0] |= 0x80;
- md[qsize - 1] |= 0x01;
- if (!BN_bin2bn(md, qsize, q)) {
- goto err;
- }
-
- // step 4
- r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, use_random_seed, cb);
- if (r > 0) {
- break;
- }
- if (r != 0) {
- goto err;
- }
-
- // do a callback call
- // step 5
- }
-
- if (!BN_GENCB_call(cb, 2, 0) || !BN_GENCB_call(cb, 3, 0)) {
- goto err;
- }
-
- // step 6
- counter = 0;
- // "offset = 2"
-
- n = (bits - 1) / 160;
-
- for (;;) {
- if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) {
- goto err;
- }
-
- // step 7
- BN_zero(W);
- // now 'buf' contains "SEED + offset - 1"
- for (k = 0; k <= n; k++) {
- // obtain "SEED + offset + k" by incrementing:
- for (i = qsize - 1; i < qsize; i--) {
- buf[i]++;
- if (buf[i] != 0) {
- break;
- }
- }
-
- if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL)) {
- goto err;
- }
-
- // step 8
- if (!BN_bin2bn(md, qsize, r0) ||
- !BN_lshift(r0, r0, (qsize << 3) * k) ||
- !BN_add(W, W, r0)) {
- goto err;
- }
- }
-
- // more of step 8
- if (!BN_mask_bits(W, bits - 1) ||
- !BN_copy(X, W) ||
- !BN_add(X, X, test)) {
- goto err;
- }
-
- // step 9
- if (!BN_lshift1(r0, q) ||
- !BN_mod(c, X, r0, ctx) ||
- !BN_sub(r0, c, BN_value_one()) ||
- !BN_sub(p, X, r0)) {
- goto err;
- }
-
- // step 10
- if (BN_cmp(p, test) >= 0) {
- // step 11
- r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb);
- if (r > 0) {
- goto end; // found it
- }
- if (r != 0) {
- goto err;
- }
- }
-
- // step 13
- counter++;
- // "offset = offset + n + 1"
-
- // step 14
- if (counter >= 4096) {
- break;
- }
- }
- }
- end:
- if (!BN_GENCB_call(cb, 2, 1)) {
- goto err;
- }
-
- // We now need to generate g
- // Set r0=(p-1)/q
- if (!BN_sub(test, p, BN_value_one()) ||
- !BN_div(r0, NULL, test, q, ctx)) {
- goto err;
- }
-
- mont = BN_MONT_CTX_new_for_modulus(p, ctx);
- if (mont == NULL ||
- !BN_set_word(test, h)) {
- goto err;
- }
-
- for (;;) {
- // g=test^r0%p
- if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) {
- goto err;
- }
- if (!BN_is_one(g)) {
- break;
- }
- if (!BN_add(test, test, BN_value_one())) {
- goto err;
- }
- h++;
- }
-
- if (!BN_GENCB_call(cb, 3, 1)) {
- goto err;
- }
-
- ok = 1;
-
- err:
- if (ok) {
- BN_free(dsa->p);
- BN_free(dsa->q);
- BN_free(dsa->g);
- dsa->p = BN_dup(p);
- dsa->q = BN_dup(q);
- dsa->g = BN_dup(g);
- if (dsa->p == NULL || dsa->q == NULL || dsa->g == NULL) {
- ok = 0;
- goto err;
- }
- if (out_counter != NULL) {
- *out_counter = counter;
- }
- if (out_h != NULL) {
- *out_h = h;
- }
- }
-
- if (ctx) {
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- }
-
- BN_MONT_CTX_free(mont);
-
- return ok;
- }
-
- DSA *DSAparams_dup(const DSA *dsa) {
- DSA *ret = DSA_new();
- if (ret == NULL) {
- return NULL;
- }
- ret->p = BN_dup(dsa->p);
- ret->q = BN_dup(dsa->q);
- ret->g = BN_dup(dsa->g);
- if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
- DSA_free(ret);
- return NULL;
- }
- return ret;
- }
-
- int DSA_generate_key(DSA *dsa) {
- int ok = 0;
- BN_CTX *ctx = NULL;
- BIGNUM *pub_key = NULL, *priv_key = NULL;
-
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
-
- priv_key = dsa->priv_key;
- if (priv_key == NULL) {
- priv_key = BN_new();
- if (priv_key == NULL) {
- goto err;
- }
- }
-
- if (!BN_rand_range_ex(priv_key, 1, dsa->q)) {
- goto err;
- }
-
- pub_key = dsa->pub_key;
- if (pub_key == NULL) {
- pub_key = BN_new();
- if (pub_key == NULL) {
- goto err;
- }
- }
-
- if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p, &dsa->method_mont_lock,
- dsa->p, ctx) ||
- !BN_mod_exp_mont_consttime(pub_key, dsa->g, priv_key, dsa->p, ctx,
- dsa->method_mont_p)) {
- goto err;
- }
-
- dsa->priv_key = priv_key;
- dsa->pub_key = pub_key;
- ok = 1;
-
- err:
- if (dsa->pub_key == NULL) {
- BN_free(pub_key);
- }
- if (dsa->priv_key == NULL) {
- BN_free(priv_key);
- }
- BN_CTX_free(ctx);
-
- return ok;
- }
-
- DSA_SIG *DSA_SIG_new(void) {
- DSA_SIG *sig;
- sig = OPENSSL_malloc(sizeof(DSA_SIG));
- if (!sig) {
- return NULL;
- }
- sig->r = NULL;
- sig->s = NULL;
- return sig;
- }
-
- void DSA_SIG_free(DSA_SIG *sig) {
- if (!sig) {
- return;
- }
-
- BN_free(sig->r);
- BN_free(sig->s);
- OPENSSL_free(sig);
- }
-
- // mod_mul_consttime sets |r| to |a| * |b| modulo |mont->N|, treating |a| and
- // |b| as secret. This function internally uses Montgomery reduction, but
- // neither inputs nor outputs are in Montgomery form.
- static int mod_mul_consttime(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
- const BN_MONT_CTX *mont, BN_CTX *ctx) {
- BN_CTX_start(ctx);
- BIGNUM *tmp = BN_CTX_get(ctx);
- // |BN_mod_mul_montgomery| removes a factor of R, so we cancel it with a
- // single |BN_to_montgomery| which adds one factor of R.
- int ok = tmp != NULL &&
- BN_to_montgomery(tmp, a, mont, ctx) &&
- BN_mod_mul_montgomery(r, tmp, b, mont, ctx);
- BN_CTX_end(ctx);
- return ok;
- }
-
- DSA_SIG *DSA_do_sign(const uint8_t *digest, size_t digest_len, const DSA *dsa) {
- BIGNUM *kinv = NULL, *r = NULL, *s = NULL;
- BIGNUM m;
- BIGNUM xr;
- BN_CTX *ctx = NULL;
- int reason = ERR_R_BN_LIB;
- DSA_SIG *ret = NULL;
-
- BN_init(&m);
- BN_init(&xr);
-
- if (!dsa->p || !dsa->q || !dsa->g) {
- reason = DSA_R_MISSING_PARAMETERS;
- goto err;
- }
-
- // We only support DSA keys that are a multiple of 8 bits. (This is a weaker
- // check than the one in |DSA_do_check_signature|, which only allows 160-,
- // 224-, and 256-bit keys.
- if (BN_num_bits(dsa->q) % 8 != 0) {
- reason = DSA_R_BAD_Q_VALUE;
- goto err;
- }
-
- s = BN_new();
- if (s == NULL) {
- goto err;
- }
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
-
- redo:
- if (!dsa_sign_setup(dsa, ctx, &kinv, &r)) {
- goto err;
- }
-
- if (digest_len > BN_num_bytes(dsa->q)) {
- // If the digest length is greater than the size of |dsa->q| use the
- // BN_num_bits(dsa->q) leftmost bits of the digest, see FIPS 186-3, 4.2.
- // Note the above check that |dsa->q| is a multiple of 8 bits.
- digest_len = BN_num_bytes(dsa->q);
- }
-
- if (BN_bin2bn(digest, digest_len, &m) == NULL) {
- goto err;
- }
-
- // |m| is bounded by 2^(num_bits(q)), which is slightly looser than q. This
- // violates |bn_mod_add_consttime| and |mod_mul_consttime|'s preconditions.
- // (The underlying algorithms could accept looser bounds, but we reduce for
- // simplicity.)
- size_t q_width = bn_minimal_width(dsa->q);
- if (!bn_resize_words(&m, q_width) ||
- !bn_resize_words(&xr, q_width)) {
- goto err;
- }
- bn_reduce_once_in_place(m.d, 0 /* no carry word */, dsa->q->d,
- xr.d /* scratch space */, q_width);
-
- // Compute s = inv(k) (m + xr) mod q. Note |dsa->method_mont_q| is
- // initialized by |dsa_sign_setup|.
- if (!mod_mul_consttime(&xr, dsa->priv_key, r, dsa->method_mont_q, ctx) ||
- !bn_mod_add_consttime(s, &xr, &m, dsa->q, ctx) ||
- !mod_mul_consttime(s, s, kinv, dsa->method_mont_q, ctx)) {
- goto err;
- }
-
- // Redo if r or s is zero as required by FIPS 186-3: this is
- // very unlikely.
- if (BN_is_zero(r) || BN_is_zero(s)) {
- goto redo;
- }
- ret = DSA_SIG_new();
- if (ret == NULL) {
- goto err;
- }
- ret->r = r;
- ret->s = s;
-
- err:
- if (ret == NULL) {
- OPENSSL_PUT_ERROR(DSA, reason);
- BN_free(r);
- BN_free(s);
- }
- BN_CTX_free(ctx);
- BN_clear_free(&m);
- BN_clear_free(&xr);
- BN_clear_free(kinv);
-
- return ret;
- }
-
- int DSA_do_verify(const uint8_t *digest, size_t digest_len, DSA_SIG *sig,
- const DSA *dsa) {
- int valid;
- if (!DSA_do_check_signature(&valid, digest, digest_len, sig, dsa)) {
- return -1;
- }
- return valid;
- }
-
- int DSA_do_check_signature(int *out_valid, const uint8_t *digest,
- size_t digest_len, DSA_SIG *sig, const DSA *dsa) {
- BN_CTX *ctx;
- BIGNUM u1, u2, t1;
- int ret = 0;
- unsigned i;
-
- *out_valid = 0;
-
- if (!dsa->p || !dsa->q || !dsa->g) {
- OPENSSL_PUT_ERROR(DSA, DSA_R_MISSING_PARAMETERS);
- return 0;
- }
-
- i = BN_num_bits(dsa->q);
- // FIPS 186-3 allows only different sizes for q.
- if (i != 160 && i != 224 && i != 256) {
- OPENSSL_PUT_ERROR(DSA, DSA_R_BAD_Q_VALUE);
- return 0;
- }
-
- if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) {
- OPENSSL_PUT_ERROR(DSA, DSA_R_MODULUS_TOO_LARGE);
- return 0;
- }
-
- BN_init(&u1);
- BN_init(&u2);
- BN_init(&t1);
-
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
-
- if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
- BN_ucmp(sig->r, dsa->q) >= 0) {
- ret = 1;
- goto err;
- }
- if (BN_is_zero(sig->s) || BN_is_negative(sig->s) ||
- BN_ucmp(sig->s, dsa->q) >= 0) {
- ret = 1;
- goto err;
- }
-
- // Calculate W = inv(S) mod Q
- // save W in u2
- if (BN_mod_inverse(&u2, sig->s, dsa->q, ctx) == NULL) {
- goto err;
- }
-
- // save M in u1
- if (digest_len > (i >> 3)) {
- // if the digest length is greater than the size of q use the
- // BN_num_bits(dsa->q) leftmost bits of the digest, see
- // fips 186-3, 4.2
- digest_len = (i >> 3);
- }
-
- if (BN_bin2bn(digest, digest_len, &u1) == NULL) {
- goto err;
- }
-
- // u1 = M * w mod q
- if (!BN_mod_mul(&u1, &u1, &u2, dsa->q, ctx)) {
- goto err;
- }
-
- // u2 = r * w mod q
- if (!BN_mod_mul(&u2, sig->r, &u2, dsa->q, ctx)) {
- goto err;
- }
-
- if (!BN_MONT_CTX_set_locked((BN_MONT_CTX **)&dsa->method_mont_p,
- (CRYPTO_MUTEX *)&dsa->method_mont_lock, dsa->p,
- ctx)) {
- goto err;
- }
-
- if (!BN_mod_exp2_mont(&t1, dsa->g, &u1, dsa->pub_key, &u2, dsa->p, ctx,
- dsa->method_mont_p)) {
- goto err;
- }
-
- // BN_copy(&u1,&t1);
- // let u1 = u1 mod q
- if (!BN_mod(&u1, &t1, dsa->q, ctx)) {
- goto err;
- }
-
- // V is now in u1. If the signature is correct, it will be
- // equal to R.
- *out_valid = BN_ucmp(&u1, sig->r) == 0;
- ret = 1;
-
- err:
- if (ret != 1) {
- OPENSSL_PUT_ERROR(DSA, ERR_R_BN_LIB);
- }
- BN_CTX_free(ctx);
- BN_free(&u1);
- BN_free(&u2);
- BN_free(&t1);
-
- return ret;
- }
-
- int DSA_sign(int type, const uint8_t *digest, size_t digest_len,
- uint8_t *out_sig, unsigned int *out_siglen, const DSA *dsa) {
- DSA_SIG *s;
-
- s = DSA_do_sign(digest, digest_len, dsa);
- if (s == NULL) {
- *out_siglen = 0;
- return 0;
- }
-
- *out_siglen = i2d_DSA_SIG(s, &out_sig);
- DSA_SIG_free(s);
- return 1;
- }
-
- int DSA_verify(int type, const uint8_t *digest, size_t digest_len,
- const uint8_t *sig, size_t sig_len, const DSA *dsa) {
- int valid;
- if (!DSA_check_signature(&valid, digest, digest_len, sig, sig_len, dsa)) {
- return -1;
- }
- return valid;
- }
-
- int DSA_check_signature(int *out_valid, const uint8_t *digest,
- size_t digest_len, const uint8_t *sig, size_t sig_len,
- const DSA *dsa) {
- DSA_SIG *s = NULL;
- int ret = 0;
- uint8_t *der = NULL;
-
- s = DSA_SIG_new();
- if (s == NULL) {
- goto err;
- }
-
- const uint8_t *sigp = sig;
- if (d2i_DSA_SIG(&s, &sigp, sig_len) == NULL || sigp != sig + sig_len) {
- goto err;
- }
-
- // Ensure that the signature uses DER and doesn't have trailing garbage.
- int der_len = i2d_DSA_SIG(s, &der);
- if (der_len < 0 || (size_t)der_len != sig_len ||
- OPENSSL_memcmp(sig, der, sig_len)) {
- goto err;
- }
-
- ret = DSA_do_check_signature(out_valid, digest, digest_len, s, dsa);
-
- err:
- OPENSSL_free(der);
- DSA_SIG_free(s);
- return ret;
- }
-
- // der_len_len returns the number of bytes needed to represent a length of |len|
- // in DER.
- static size_t der_len_len(size_t len) {
- if (len < 0x80) {
- return 1;
- }
- size_t ret = 1;
- while (len > 0) {
- ret++;
- len >>= 8;
- }
- return ret;
- }
-
- int DSA_size(const DSA *dsa) {
- size_t order_len = BN_num_bytes(dsa->q);
- // Compute the maximum length of an |order_len| byte integer. Defensively
- // assume that the leading 0x00 is included.
- size_t integer_len = 1 /* tag */ + der_len_len(order_len + 1) + 1 + order_len;
- if (integer_len < order_len) {
- return 0;
- }
- // A DSA signature is two INTEGERs.
- size_t value_len = 2 * integer_len;
- if (value_len < integer_len) {
- return 0;
- }
- // Add the header.
- size_t ret = 1 /* tag */ + der_len_len(value_len) + value_len;
- if (ret < value_len) {
- return 0;
- }
- return ret;
- }
-
- static int dsa_sign_setup(const DSA *dsa, BN_CTX *ctx_in, BIGNUM **out_kinv,
- BIGNUM **out_r) {
- BN_CTX *ctx;
- BIGNUM k, *kinv = NULL, *r = NULL;
- int ret = 0;
-
- if (!dsa->p || !dsa->q || !dsa->g) {
- OPENSSL_PUT_ERROR(DSA, DSA_R_MISSING_PARAMETERS);
- return 0;
- }
-
- BN_init(&k);
-
- ctx = ctx_in;
- if (ctx == NULL) {
- ctx = BN_CTX_new();
- if (ctx == NULL) {
- goto err;
- }
- }
-
- r = BN_new();
- kinv = BN_new();
- if (r == NULL || kinv == NULL ||
- // Get random k
- !BN_rand_range_ex(&k, 1, dsa->q) ||
- !BN_MONT_CTX_set_locked((BN_MONT_CTX **)&dsa->method_mont_p,
- (CRYPTO_MUTEX *)&dsa->method_mont_lock, dsa->p,
- ctx) ||
- !BN_MONT_CTX_set_locked((BN_MONT_CTX **)&dsa->method_mont_q,
- (CRYPTO_MUTEX *)&dsa->method_mont_lock, dsa->q,
- ctx) ||
- // Compute r = (g^k mod p) mod q
- !BN_mod_exp_mont_consttime(r, dsa->g, &k, dsa->p, ctx,
- dsa->method_mont_p) ||
- // Note |BN_mod| below is not constant-time and may leak information about
- // |r|. |dsa->p| may be significantly larger than |dsa->q|, so this is not
- // easily performed in constant-time with Montgomery reduction.
- //
- // However, |r| at this point is g^k (mod p). It is almost the value of
- // |r| revealed in the signature anyway (g^k (mod p) (mod q)), going from
- // it to |k| would require computing a discrete log.
- !BN_mod(r, r, dsa->q, ctx) ||
- // Compute part of 's = inv(k) (m + xr) mod q' using Fermat's Little
- // Theorem.
- !bn_mod_inverse_prime(kinv, &k, dsa->q, ctx, dsa->method_mont_q)) {
- goto err;
- }
-
- BN_clear_free(*out_kinv);
- *out_kinv = kinv;
- kinv = NULL;
- BN_clear_free(*out_r);
- *out_r = r;
- ret = 1;
-
- err:
- if (!ret) {
- OPENSSL_PUT_ERROR(DSA, ERR_R_BN_LIB);
- if (r != NULL) {
- BN_clear_free(r);
- }
- }
-
- if (ctx_in == NULL) {
- BN_CTX_free(ctx);
- }
- BN_clear_free(&k);
- BN_clear_free(kinv);
- return ret;
- }
-
- int DSA_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
- CRYPTO_EX_dup *dup_unused, CRYPTO_EX_free *free_func) {
- int index;
- if (!CRYPTO_get_ex_new_index(&g_ex_data_class, &index, argl, argp,
- free_func)) {
- return -1;
- }
- return index;
- }
-
- int DSA_set_ex_data(DSA *dsa, int idx, void *arg) {
- return CRYPTO_set_ex_data(&dsa->ex_data, idx, arg);
- }
-
- void *DSA_get_ex_data(const DSA *dsa, int idx) {
- return CRYPTO_get_ex_data(&dsa->ex_data, idx);
- }
-
- DH *DSA_dup_DH(const DSA *dsa) {
- if (dsa == NULL) {
- return NULL;
- }
-
- DH *ret = DH_new();
- if (ret == NULL) {
- goto err;
- }
- if (dsa->q != NULL) {
- ret->priv_length = BN_num_bits(dsa->q);
- if ((ret->q = BN_dup(dsa->q)) == NULL) {
- goto err;
- }
- }
- if ((dsa->p != NULL && (ret->p = BN_dup(dsa->p)) == NULL) ||
- (dsa->g != NULL && (ret->g = BN_dup(dsa->g)) == NULL) ||
- (dsa->pub_key != NULL && (ret->pub_key = BN_dup(dsa->pub_key)) == NULL) ||
- (dsa->priv_key != NULL &&
- (ret->priv_key = BN_dup(dsa->priv_key)) == NULL)) {
- goto err;
- }
-
- return ret;
-
- err:
- DH_free(ret);
- return NULL;
- }
|