TLS1.3 FFDHE Support

[openssl.git] / crypto / dh / dh_key.c

diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c
index 204e5a7a421edf9385a67daa96e30c9bcb6bdee8..6b3a1247b2524e224e00648864e400975b88fd97 100644 (file)
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -1,7 +1,7 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2018 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
@@ -56,20 +56,37 @@ static DH_METHOD dh_ossl = {
     NULL
 };
 
+static const DH_METHOD *default_DH_method = &dh_ossl;
+
 const DH_METHOD *DH_OpenSSL(void)
 {
     return &dh_ossl;
 }
 
+void DH_set_default_method(const DH_METHOD *meth)
+{
+    default_DH_method = meth;
+}
+
+const DH_METHOD *DH_get_default_method(void)
+{
+    return default_DH_method;
+}
+
 static int generate_key(DH *dh)
 {
     int ok = 0;
     int generate_new_key = 0;
     unsigned l;
-    BN_CTX *ctx;
+    BN_CTX *ctx = NULL;
     BN_MONT_CTX *mont = NULL;
     BIGNUM *pub_key = NULL, *priv_key = NULL;
 
+    if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS) {
+        DHerr(DH_F_GENERATE_KEY, DH_R_MODULUS_TOO_LARGE);
+        return 0;
+    }
+
     ctx = BN_CTX_new();
     if (ctx == NULL)
         goto err;
@@ -99,14 +116,14 @@ static int generate_key(DH *dh)
     if (generate_new_key) {
         if (dh->q) {
             do {
-                if (!BN_rand_range(priv_key, dh->q))
+                if (!BN_priv_rand_range(priv_key, dh->q))
                     goto err;
             }
             while (BN_is_zero(priv_key) || BN_is_one(priv_key));
         } 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))
+            if (!BN_priv_rand(priv_key, l, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY))
                 goto err;
         }
     }
@@ -138,7 +155,7 @@ static int generate_key(DH *dh)
     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)
@@ -188,11 +205,9 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 
     ret = BN_bn2bin(tmp, key);
  err:
-    if (ctx != NULL) {
-        BN_CTX_end(ctx);
-        BN_CTX_free(ctx);
-    }
-    return (ret);
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    return ret;
 }
 
 static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
@@ -205,11 +220,74 @@ static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
 static int dh_init(DH *dh)
 {
     dh->flags |= DH_FLAG_CACHE_MONT_P;
-    return (1);
+    return 1;
 }
 
 static int dh_finish(DH *dh)
 {
     BN_MONT_CTX_free(dh->method_mont_p);
-    return (1);
+    return 1;
+}
+
+int dh_buf2key(DH *dh, const unsigned char *buf, size_t len)
+{
+    int err_reason = DH_R_BN_ERROR;
+    BIGNUM *pubkey = NULL;
+    const BIGNUM *p;
+    size_t p_size;
+
+    if ((pubkey = BN_bin2bn(buf, len, NULL)) == NULL)
+        goto err;
+    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;
+    }
+    /*
+     * 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_set0_key(dh, pubkey, NULL) != 1)
+        goto err;
+    return 1;
+err:
+    DHerr(DH_F_DH_BUF2KEY, err_reason);
+    BN_free(pubkey);
+    return 0;
+}
+
+size_t dh_key2buf(const DH *dh, unsigned char **pbuf_out)
+{
+    const BIGNUM *pubkey;
+    unsigned char *pbuf;
+    const BIGNUM *p;
+    int p_size;
+
+    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;
 }