X-Git-Url: https://git.openssl.org/?a=blobdiff_plain;f=crypto%2Fdh%2Fdh_key.c;h=918949d95365acb7980f88542a972c19b4addaee;hb=738ee1819e3bb94723701fb505ce2971afe47a9b;hp=fe021904ccc86c633427d9cdbe9ee8a56800c3ad;hpb=2301d91dd58d9827865e360d616291f2549ec5bf;p=openssl.git

diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c
index fe021904cc..918949d953 100644
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -1,42 +1,119 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
  *
- * Licensed under the OpenSSL license (the "License").  You may not use
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
  */
 
+/*
+ * DH low level APIs are deprecated for public use, but still ok for
+ * internal use.
+ */
+#include "internal/deprecated.h"
+
 #include <stdio.h>
 #include "internal/cryptlib.h"
-#include "dh_locl.h"
-#include "internal/bn_int.h"
+#include "dh_local.h"
+#include "crypto/bn.h"
+#include "crypto/dh.h"
+#include "crypto/security_bits.h"
+
+#ifdef FIPS_MODE
+# define MIN_STRENGTH 112
+#else
+# define MIN_STRENGTH 80
+#endif
 
 static int generate_key(DH *dh);
-static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
 static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
                          const BIGNUM *a, const BIGNUM *p,
                          const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx);
 static int dh_init(DH *dh);
 static int dh_finish(DH *dh);
 
-int DH_generate_key(DH *dh)
+static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 {
-    return dh->meth->generate_key(dh);
+    BN_CTX *ctx = NULL;
+    BN_MONT_CTX *mont = NULL;
+    BIGNUM *tmp;
+    int ret = -1;
+#ifndef FIPS_MODE
+    int check_result;
+#endif
+
+    if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS) {
+        DHerr(0, DH_R_MODULUS_TOO_LARGE);
+        goto err;
+    }
+
+    if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS) {
+        DHerr(0, DH_R_MODULUS_TOO_SMALL);
+        return 0;
+    }
+
+    ctx = BN_CTX_new_ex(dh->libctx);
+    if (ctx == NULL)
+        goto err;
+    BN_CTX_start(ctx);
+    tmp = BN_CTX_get(ctx);
+    if (tmp == NULL)
+        goto err;
+
+    if (dh->priv_key == NULL) {
+        DHerr(0, DH_R_NO_PRIVATE_VALUE);
+        goto err;
+    }
+
+    if (dh->flags & DH_FLAG_CACHE_MONT_P) {
+        mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
+                                      dh->lock, dh->params.p, ctx);
+        BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
+        if (!mont)
+            goto err;
+    }
+/* TODO(3.0) : Solve in a PR related to Key validation for DH */
+#ifndef FIPS_MODE
+    if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
+        DHerr(0, DH_R_INVALID_PUBKEY);
+        goto err;
+    }
+#endif
+    if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->params.p, ctx,
+                              mont)) {
+        DHerr(0, ERR_R_BN_LIB);
+        goto err;
+    }
+
+    ret = BN_bn2bin(tmp, key);
+ err:
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    return ret;
 }
 
 int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 {
+#ifdef FIPS_MODE
+    return compute_key(key, pub_key, dh);
+#else
     return dh->meth->compute_key(key, pub_key, dh);
+#endif
 }
 
 int DH_compute_key_padded(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 {
     int rv, pad;
+
+#ifdef FIPS_MODE
+    rv = compute_key(key, pub_key, dh);
+#else
     rv = dh->meth->compute_key(key, pub_key, dh);
+#endif
     if (rv <= 0)
         return rv;
-    pad = BN_num_bytes(dh->p) - rv;
+    pad = BN_num_bytes(dh->params.p) - rv;
     if (pad > 0) {
         memmove(key + pad, key, rv);
         memset(key, 0, pad);
@@ -56,21 +133,104 @@ static DH_METHOD dh_ossl = {
     NULL
 };
 
+static const DH_METHOD *default_DH_method = &dh_ossl;
+
 const DH_METHOD *DH_OpenSSL(void)
 {
     return &dh_ossl;
 }
 
+const DH_METHOD *DH_get_default_method(void)
+{
+    return default_DH_method;
+}
+
+static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
+                         const BIGNUM *a, const BIGNUM *p,
+                         const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
+{
+    return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
+}
+
+static int dh_init(DH *dh)
+{
+    dh->flags |= DH_FLAG_CACHE_MONT_P;
+    ffc_params_init(&dh->params);
+    dh->dirty_cnt++;
+    return 1;
+}
+
+static int dh_finish(DH *dh)
+{
+    BN_MONT_CTX_free(dh->method_mont_p);
+    return 1;
+}
+
+#ifndef FIPS_MODE
+void DH_set_default_method(const DH_METHOD *meth)
+{
+    default_DH_method = meth;
+}
+#endif /* FIPS_MODE */
+
+int DH_generate_key(DH *dh)
+{
+#ifdef FIPS_MODE
+    return generate_key(dh);
+#else
+    return dh->meth->generate_key(dh);
+#endif
+}
+
+int dh_generate_public_key(BN_CTX *ctx, DH *dh, const BIGNUM *priv_key,
+                           BIGNUM *pub_key)
+{
+    int ret = 0;
+    BIGNUM *prk = BN_new();
+    BN_MONT_CTX *mont = NULL;
+
+    if (prk == NULL)
+        return 0;
+
+    if (dh->flags & DH_FLAG_CACHE_MONT_P) {
+        mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
+                                      dh->lock, dh->params.p, ctx);
+        if (mont == NULL)
+            goto err;
+    }
+    BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
+
+    /* pub_key = g^priv_key mod p */
+    if (!dh->meth->bn_mod_exp(dh, pub_key, dh->params.g, prk, dh->params.p,
+                              ctx, mont))
+        goto err;
+    ret = 1;
+err:
+    BN_clear_free(prk);
+    return ret;
+}
+
 static int generate_key(DH *dh)
 {
     int ok = 0;
     int generate_new_key = 0;
+#ifndef FIPS_MODE
     unsigned l;
-    BN_CTX *ctx;
-    BN_MONT_CTX *mont = NULL;
+#endif
+    BN_CTX *ctx = NULL;
     BIGNUM *pub_key = NULL, *priv_key = NULL;
 
-    ctx = BN_CTX_new();
+    if (BN_num_bits(dh->params.p) > OPENSSL_DH_MAX_MODULUS_BITS) {
+        DHerr(0, DH_R_MODULUS_TOO_LARGE);
+        return 0;
+    }
+
+    if (BN_num_bits(dh->params.p) < DH_MIN_MODULUS_BITS) {
+        DHerr(0, DH_R_MODULUS_TOO_SMALL);
+        return 0;
+    }
+
+    ctx = BN_CTX_new_ex(dh->libctx);
     if (ctx == NULL)
         goto err;
 
@@ -79,135 +239,146 @@ static int generate_key(DH *dh)
         if (priv_key == NULL)
             goto err;
         generate_new_key = 1;
-    } else
+    } else {
         priv_key = dh->priv_key;
+    }
 
     if (dh->pub_key == NULL) {
         pub_key = BN_new();
         if (pub_key == NULL)
             goto err;
-    } else
+    } else {
         pub_key = dh->pub_key;
-
-    if (dh->flags & DH_FLAG_CACHE_MONT_P) {
-        mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
-                                      dh->lock, dh->p, ctx);
-        if (!mont)
-            goto err;
     }
-
     if (generate_new_key) {
-        if (dh->q) {
-            do {
-                if (!BN_rand_range(priv_key, dh->q))
-                    goto err;
-            }
-            while (BN_is_zero(priv_key) || BN_is_one(priv_key));
+        /* Is it an approved safe prime ?*/
+        if (DH_get_nid(dh) != NID_undef) {
+            int max_strength =
+                    ifc_ffc_compute_security_bits(BN_num_bits(dh->params.p));
+
+            if (dh->params.q == NULL
+                || dh->length > BN_num_bits(dh->params.q))
+                goto err;
+            /* dh->length = maximum bit length of generated private key */
+            if (!ffc_generate_private_key(ctx, &dh->params, dh->length,
+                                          max_strength, priv_key))
+                goto err;
         } else {
-            /* secret exponent length */
-            l = dh->length ? dh->length : BN_num_bits(dh->p) - 1;
-            if (!BN_rand(priv_key, l, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY))
+#ifdef FIPS_MODE
+            if (dh->params.q == NULL)
                 goto err;
+#else
+            if (dh->params.q == NULL) {
+                /* secret exponent length */
+                l = dh->length ? dh->length : BN_num_bits(dh->params.p) - 1;
+                if (!BN_priv_rand_ex(priv_key, l, BN_RAND_TOP_ONE,
+                                     BN_RAND_BOTTOM_ANY, ctx))
+                    goto err;
+                /*
+                 * We handle just one known case where g is a quadratic non-residue:
+                 * for g = 2: p % 8 == 3
+                 */
+                if (BN_is_word(dh->params.g, DH_GENERATOR_2)
+                    && !BN_is_bit_set(dh->params.p, 2)) {
+                    /* clear bit 0, since it won't be a secret anyway */
+                    if (!BN_clear_bit(priv_key, 0))
+                        goto err;
+                }
+            } else
+#endif
+            {
+                /*
+                 * For FFC FIPS 186-4 keygen
+                 * security strength s = 112,
+                 * Max Private key size N = len(q)
+                 */
+                if (!ffc_generate_private_key(ctx, &dh->params,
+                                              BN_num_bits(dh->params.q),
+                                              MIN_STRENGTH,
+                                              priv_key))
+                    goto err;
+            }
         }
     }
 
-    {
-        BIGNUM *prk = BN_new();
-
-        if (prk == NULL)
-            goto err;
-        BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
-
-        if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) {
-            BN_free(prk);
-            goto err;
-        }
-        /* We MUST free prk before any further use of priv_key */
-        BN_free(prk);
-    }
+    if (!dh_generate_public_key(ctx, dh, priv_key, pub_key))
+        goto err;
 
     dh->pub_key = pub_key;
     dh->priv_key = priv_key;
+    dh->dirty_cnt++;
     ok = 1;
  err:
     if (ok != 1)
-        DHerr(DH_F_GENERATE_KEY, ERR_R_BN_LIB);
+        DHerr(0, ERR_R_BN_LIB);
 
     if (pub_key != dh->pub_key)
         BN_free(pub_key);
     if (priv_key != dh->priv_key)
         BN_free(priv_key);
     BN_CTX_free(ctx);
-    return (ok);
+    return ok;
 }
 
-static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
+int dh_buf2key(DH *dh, const unsigned char *buf, size_t len)
 {
-    BN_CTX *ctx = NULL;
-    BN_MONT_CTX *mont = NULL;
-    BIGNUM *tmp;
-    int ret = -1;
-    int check_result;
+    int err_reason = DH_R_BN_ERROR;
+    BIGNUM *pubkey = NULL;
+    const BIGNUM *p;
+    size_t p_size;
 
-    if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
-        DHerr(DH_F_COMPUTE_KEY, DH_R_MODULUS_TOO_LARGE);
+    if ((pubkey = BN_bin2bn(buf, len, NULL)) == NULL)
         goto err;
-    }
-
-    ctx = BN_CTX_new();
-    if (ctx == NULL)
-        goto err;
-    BN_CTX_start(ctx);
-    tmp = BN_CTX_get(ctx);
-
-    if (dh->priv_key == NULL) {
-        DHerr(DH_F_COMPUTE_KEY, DH_R_NO_PRIVATE_VALUE);
+    DH_get0_pqg(dh, &p, NULL, NULL);
+    if (p == NULL || (p_size = BN_num_bytes(p)) == 0) {
+        err_reason = DH_R_NO_PARAMETERS_SET;
         goto err;
     }
-
-    if (dh->flags & DH_FLAG_CACHE_MONT_P) {
-        mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
-                                      dh->lock, dh->p, ctx);
-        BN_set_flags(dh->priv_key, BN_FLG_CONSTTIME);
-        if (!mont)
-            goto err;
-    }
-
-    if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result) {
-        DHerr(DH_F_COMPUTE_KEY, DH_R_INVALID_PUBKEY);
+    /*
+     * As per Section 4.2.8.1 of RFC 8446 fail if DHE's
+     * public key is of size not equal to size of p
+     */
+    if (BN_is_zero(pubkey) || p_size != len) {
+        err_reason = DH_R_INVALID_PUBKEY;
         goto err;
     }
-
-    if (!dh->
-        meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key, dh->p, ctx, mont)) {
-        DHerr(DH_F_COMPUTE_KEY, ERR_R_BN_LIB);
+    if (DH_set0_key(dh, pubkey, NULL) != 1)
         goto err;
-    }
-
-    ret = BN_bn2bin(tmp, key);
- err:
-    if (ctx != NULL) {
-        BN_CTX_end(ctx);
-        BN_CTX_free(ctx);
-    }
-    return (ret);
+    return 1;
+err:
+    DHerr(DH_F_DH_BUF2KEY, err_reason);
+    BN_free(pubkey);
+    return 0;
 }
 
-static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
-                         const BIGNUM *a, const BIGNUM *p,
-                         const BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *m_ctx)
+size_t dh_key2buf(const DH *dh, unsigned char **pbuf_out)
 {
-    return BN_mod_exp_mont(r, a, p, m, ctx, m_ctx);
-}
+    const BIGNUM *pubkey;
+    unsigned char *pbuf;
+    const BIGNUM *p;
+    int p_size;
 
-static int dh_init(DH *dh)
-{
-    dh->flags |= DH_FLAG_CACHE_MONT_P;
-    return (1);
-}
-
-static int dh_finish(DH *dh)
-{
-    BN_MONT_CTX_free(dh->method_mont_p);
-    return (1);
+    DH_get0_pqg(dh, &p, NULL, NULL);
+    DH_get0_key(dh, &pubkey, NULL);
+    if (p == NULL || pubkey == NULL
+            || (p_size = BN_num_bytes(p)) == 0
+            || BN_num_bytes(pubkey) == 0) {
+        DHerr(DH_F_DH_KEY2BUF, DH_R_INVALID_PUBKEY);
+        return 0;
+    }
+    if ((pbuf = OPENSSL_malloc(p_size)) == NULL) {
+        DHerr(DH_F_DH_KEY2BUF, ERR_R_MALLOC_FAILURE);
+        return 0;
+    }
+    /*
+     * As per Section 4.2.8.1 of RFC 8446 left pad public
+     * key with zeros to the size of p
+     */
+    if (BN_bn2binpad(pubkey, pbuf, p_size) < 0) {
+        OPENSSL_free(pbuf);
+        DHerr(DH_F_DH_KEY2BUF, DH_R_BN_ERROR);
+        return 0;
+    }
+    *pbuf_out = pbuf;
+    return p_size;
 }