Initial Commit

openssl-1.0.2f/engines/ccgost/gost_sign.c

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+/**********************************************************************
+ *                          gost_sign.c                               *
+ *             Copyright (c) 2005-2006 Cryptocom LTD                  *
+ *         This file is distributed under the same license as OpenSSL *
+ *                                                                    *
+ *       Implementation of GOST R 34.10-94 signature algorithm        *
+ *       for OpenSSL                                                  *
+ *          Requires OpenSSL 0.9.9 for compilation                    *
+ **********************************************************************/
+#include <string.h>
+#include <openssl/rand.h>
+#include <openssl/bn.h>
+#include <openssl/dsa.h>
+#include <openssl/evp.h>
+#include <openssl/err.h>
+
+#include "gost_params.h"
+#include "gost_lcl.h"
+#include "e_gost_err.h"
+
+#ifdef DEBUG_SIGN
+void dump_signature(const char *message, const unsigned char *buffer,
+                    size_t len)
+{
+    size_t i;
+    fprintf(stderr, "signature %s Length=%d", message, len);
+    for (i = 0; i < len; i++) {
+        if (i % 16 == 0)
+            fputc('\n', stderr);
+        fprintf(stderr, " %02x", buffer[i]);
+    }
+    fprintf(stderr, "\nEnd of signature\n");
+}
+
+void dump_dsa_sig(const char *message, DSA_SIG *sig)
+{
+    fprintf(stderr, "%s\nR=", message);
+    BN_print_fp(stderr, sig->r);
+    fprintf(stderr, "\nS=");
+    BN_print_fp(stderr, sig->s);
+    fprintf(stderr, "\n");
+}
+
+#else
+
+# define dump_signature(a,b,c)
+# define dump_dsa_sig(a,b)
+#endif
+
+/*
+ * Computes signature and returns it as DSA_SIG structure
+ */
+DSA_SIG *gost_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
+{
+    BIGNUM *k = NULL, *tmp = NULL, *tmp2 = NULL;
+    DSA_SIG *newsig = NULL, *ret = NULL;
+    BIGNUM *md = hashsum2bn(dgst);
+    /* check if H(M) mod q is zero */
+    BN_CTX *ctx = BN_CTX_new();
+    if(!ctx) {
+        GOSTerr(GOST_F_GOST_DO_SIGN, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+    BN_CTX_start(ctx);
+    newsig = DSA_SIG_new();
+    if (!newsig) {
+        GOSTerr(GOST_F_GOST_DO_SIGN, GOST_R_NO_MEMORY);
+        goto err;
+    }
+    tmp = BN_CTX_get(ctx);
+    k = BN_CTX_get(ctx);
+    tmp2 = BN_CTX_get(ctx);
+    if(!tmp || !k || !tmp2) {
+        GOSTerr(GOST_F_GOST_DO_SIGN, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+    BN_mod(tmp, md, dsa->q, ctx);
+    if (BN_is_zero(tmp)) {
+        BN_one(md);
+    }
+    do {
+        do {
+            /*
+             * Generate random number k less than q
+             */
+            BN_rand_range(k, dsa->q);
+            /* generate r = (a^x mod p) mod q */
+            BN_mod_exp(tmp, dsa->g, k, dsa->p, ctx);
+            if (!(newsig->r)) {
+                newsig->r = BN_new();
+                if(!newsig->r) {
+                    GOSTerr(GOST_F_GOST_DO_SIGN, ERR_R_MALLOC_FAILURE);
+                    goto err;
+                }
+            }
+            BN_mod(newsig->r, tmp, dsa->q, ctx);
+        }
+        while (BN_is_zero(newsig->r));
+        /* generate s = (xr + k(Hm)) mod q */
+        BN_mod_mul(tmp, dsa->priv_key, newsig->r, dsa->q, ctx);
+        BN_mod_mul(tmp2, k, md, dsa->q, ctx);
+        if (!newsig->s) {
+            newsig->s = BN_new();
+            if(!newsig->s) {
+                GOSTerr(GOST_F_GOST_DO_SIGN, ERR_R_MALLOC_FAILURE);
+                goto err;
+            }
+        }
+        BN_mod_add(newsig->s, tmp, tmp2, dsa->q, ctx);
+    }
+    while (BN_is_zero(newsig->s));
+
+    ret = newsig;
+ err:
+    BN_free(md);
+    if(ctx) {
+        BN_CTX_end(ctx);
+        BN_CTX_free(ctx);
+    }
+    if(!ret && newsig) {
+        DSA_SIG_free(newsig);
+    }
+    return ret;
+}
+
+/*
+ * Packs signature according to Cryptocom rules
+ * and frees up DSA_SIG structure
+ */
+/*-
+int pack_sign_cc(DSA_SIG *s,int order,unsigned char *sig, size_t *siglen)
+        {
+        *siglen = 2*order;
+        memset(sig,0,*siglen);
+        store_bignum(s->r, sig,order);
+        store_bignum(s->s, sig + order,order);
+        dump_signature("serialized",sig,*siglen);
+        DSA_SIG_free(s);
+        return 1;
+        }
+*/
+/*
+ * Packs signature according to Cryptopro rules
+ * and frees up DSA_SIG structure
+ */
+int pack_sign_cp(DSA_SIG *s, int order, unsigned char *sig, size_t *siglen)
+{
+    *siglen = 2 * order;
+    memset(sig, 0, *siglen);
+    store_bignum(s->s, sig, order);
+    store_bignum(s->r, sig + order, order);
+    dump_signature("serialized", sig, *siglen);
+    DSA_SIG_free(s);
+    return 1;
+}
+
+/*
+ * Verifies signature passed as DSA_SIG structure
+ *
+ */
+
+int gost_do_verify(const unsigned char *dgst, int dgst_len,
+                   DSA_SIG *sig, DSA *dsa)
+{
+    BIGNUM *md = NULL, *tmp = NULL;
+    BIGNUM *q2 = NULL;
+    BIGNUM *u = NULL, *v = NULL, *z1 = NULL, *z2 = NULL;
+    BIGNUM *tmp2 = NULL, *tmp3 = NULL;
+    int ok = 0;
+    BN_CTX *ctx = BN_CTX_new();
+    if(!ctx) {
+        GOSTerr(GOST_F_GOST_DO_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    BN_CTX_start(ctx);
+    if (BN_cmp(sig->s, dsa->q) >= 1 || BN_cmp(sig->r, dsa->q) >= 1) {
+        GOSTerr(GOST_F_GOST_DO_VERIFY, GOST_R_SIGNATURE_PARTS_GREATER_THAN_Q);
+        goto err;
+    }
+    md = hashsum2bn(dgst);
+
+    tmp = BN_CTX_get(ctx);
+    v = BN_CTX_get(ctx);
+    q2 = BN_CTX_get(ctx);
+    z1 = BN_CTX_get(ctx);
+    z2 = BN_CTX_get(ctx);
+    tmp2 = BN_CTX_get(ctx);
+    tmp3 = BN_CTX_get(ctx);
+    u = BN_CTX_get(ctx);
+    if(!tmp || !v || !q2 || !z1 || !z2 || !tmp2 || !tmp3 || !u) {
+        GOSTerr(GOST_F_GOST_DO_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    BN_mod(tmp, md, dsa->q, ctx);
+    if (BN_is_zero(tmp)) {
+        BN_one(md);
+    }
+    BN_copy(q2, dsa->q);
+    BN_sub_word(q2, 2);
+    BN_mod_exp(v, md, q2, dsa->q, ctx);
+    BN_mod_mul(z1, sig->s, v, dsa->q, ctx);
+    BN_sub(tmp, dsa->q, sig->r);
+    BN_mod_mul(z2, tmp, v, dsa->p, ctx);
+    BN_mod_exp(tmp, dsa->g, z1, dsa->p, ctx);
+    BN_mod_exp(tmp2, dsa->pub_key, z2, dsa->p, ctx);
+    BN_mod_mul(tmp3, tmp, tmp2, dsa->p, ctx);
+    BN_mod(u, tmp3, dsa->q, ctx);
+    ok = (BN_cmp(u, sig->r) == 0);
+
+    if (!ok) {
+        GOSTerr(GOST_F_GOST_DO_VERIFY, GOST_R_SIGNATURE_MISMATCH);
+    }
+err:
+    if(md) BN_free(md);
+    if(ctx) {
+        BN_CTX_end(ctx);
+        BN_CTX_free(ctx);
+    }
+    return ok;
+}
+
+/*
+ * Computes public keys for GOST R 34.10-94 algorithm
+ *
+ */
+int gost94_compute_public(DSA *dsa)
+{
+    /* Now fill algorithm parameters with correct values */
+    BN_CTX *ctx;
+    if (!dsa->g) {
+        GOSTerr(GOST_F_GOST94_COMPUTE_PUBLIC, GOST_R_KEY_IS_NOT_INITALIZED);
+        return 0;
+    }
+    ctx = BN_CTX_new();
+    if(!ctx) {
+        GOSTerr(GOST_F_GOST94_COMPUTE_PUBLIC, ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+
+    dsa->pub_key = BN_new();
+    if(!dsa->pub_key) {
+        GOSTerr(GOST_F_GOST94_COMPUTE_PUBLIC, ERR_R_MALLOC_FAILURE);
+        BN_CTX_free(ctx);
+        return 0;
+    }
+    /* Compute public key  y = a^x mod p */
+    BN_mod_exp(dsa->pub_key, dsa->g, dsa->priv_key, dsa->p, ctx);
+    BN_CTX_free(ctx);
+    return 1;
+}
+
+/*
+ * Fill GOST 94 params, searching them in R3410_paramset array
+ * by nid of paramset
+ *
+ */
+int fill_GOST94_params(DSA *dsa, int nid)
+{
+    R3410_params *params = R3410_paramset;
+    while (params->nid != NID_undef && params->nid != nid)
+        params++;
+    if (params->nid == NID_undef) {
+        GOSTerr(GOST_F_FILL_GOST94_PARAMS, GOST_R_UNSUPPORTED_PARAMETER_SET);
+        return 0;
+    }
+#define dump_signature(a,b,c)
+    if (dsa->p) {
+        BN_free(dsa->p);
+    }
+    dsa->p = NULL;
+    BN_dec2bn(&(dsa->p), params->p);
+    if (dsa->q) {
+        BN_free(dsa->q);
+    }
+    dsa->q = NULL;
+    BN_dec2bn(&(dsa->q), params->q);
+    if (dsa->g) {
+        BN_free(dsa->g);
+    }
+    dsa->g = NULL;
+    BN_dec2bn(&(dsa->g), params->a);
+    return 1;
+}
+
+/*
+ *  Generate GOST R 34.10-94 keypair
+ *
+ *
+ */
+int gost_sign_keygen(DSA *dsa)
+{
+    dsa->priv_key = BN_new();
+    if(!dsa->priv_key) {
+        GOSTerr(GOST_F_GOST_SIGN_KEYGEN, ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+    BN_rand_range(dsa->priv_key, dsa->q);
+    return gost94_compute_public(dsa);
+}
+
+/* Unpack signature according to cryptocom rules  */
+/*-
+DSA_SIG *unpack_cc_signature(const unsigned char *sig,size_t siglen)
+        {
+        DSA_SIG *s;
+        s = DSA_SIG_new();
+        if (s == NULL)
+                {
+                GOSTerr(GOST_F_UNPACK_CC_SIGNATURE,GOST_R_NO_MEMORY);
+                return(NULL);
+                }
+        s->r = getbnfrombuf(sig, siglen/2);
+        s->s = getbnfrombuf(sig + siglen/2, siglen/2);
+        return s;
+        }
+*/
+/* Unpack signature according to cryptopro rules  */
+DSA_SIG *unpack_cp_signature(const unsigned char *sig, size_t siglen)
+{
+    DSA_SIG *s;
+
+    s = DSA_SIG_new();
+    if (s == NULL) {
+        GOSTerr(GOST_F_UNPACK_CP_SIGNATURE, GOST_R_NO_MEMORY);
+        return NULL;
+    }
+    s->s = getbnfrombuf(sig, siglen / 2);
+    s->r = getbnfrombuf(sig + siglen / 2, siglen / 2);
+    return s;
+}
+
+/* Convert little-endian byte array into bignum */
+BIGNUM *hashsum2bn(const unsigned char *dgst)
+{
+    unsigned char buf[32];
+    int i;
+    for (i = 0; i < 32; i++) {
+        buf[31 - i] = dgst[i];
+    }
+    return getbnfrombuf(buf, 32);
+}
+
+/* Convert byte buffer to bignum, skipping leading zeros*/
+BIGNUM *getbnfrombuf(const unsigned char *buf, size_t len)
+{
+    while (*buf == 0 && len > 0) {
+        buf++;
+        len--;
+    }
+    if (len) {
+        return BN_bin2bn(buf, len, NULL);
+    } else {
+        BIGNUM *b = BN_new();
+        BN_zero(b);
+        return b;
+    }
+}
+
+/*
+ * Pack bignum into byte buffer of given size, filling all leading bytes by
+ * zeros
+ */
+int store_bignum(BIGNUM *bn, unsigned char *buf, int len)
+{
+    int bytes = BN_num_bytes(bn);
+    if (bytes > len)
+        return 0;
+    memset(buf, 0, len);
+    BN_bn2bin(bn, buf + len - bytes);
+    return 1;
+}