MEDIUM: ssl: Add standardized DH parameters >= 1024 bits

This patch adds standardized (rfc 2409 / rfc 3526)
DH parameters with prime lengths of 1024, 2048, 3072, 4096, 6144 and
8192 bits, based on the private key size.

diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index a11aed24d209d22f1f816145c86b597682b66bee..f7c50c56845a3fe42ea56cafaa3c0ed700e4cffd 100644 (file)
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -270,36 +270,149 @@ static int ssl_sock_switchctx_cbk(SSL *ssl, int *al, struct bind_conf *s)
 #endif /* SSL_CTRL_SET_TLSEXT_HOSTNAME */
 
 #ifndef OPENSSL_NO_DH
+
+static DH *ssl_get_dh_1024(void)
+{
+       DH *dh = DH_new();
+       if (dh) {
+               dh->p = get_rfc2409_prime_1024(NULL);
+               /* See RFC 2409, Section 6 "Oakley Groups"
+                  for the reason why we use 2 as a generator.
+               */
+               BN_dec2bn(&dh->g, "2");
+               if (!dh->p || !dh->g) {
+                       DH_free(dh);
+                       dh = NULL;
+               }
+       }
+       return dh;
+}
+
+static DH *ssl_get_dh_2048(void)
+{
+       DH *dh = DH_new();
+       if (dh) {
+               dh->p = get_rfc3526_prime_2048(NULL);
+               /* See RFC 3526, Section 3 "2048-bit MODP Group"
+                  for the reason why we use 2 as a generator.
+                */
+               BN_dec2bn(&dh->g, "2");
+               if (!dh->p || !dh->g) {
+                       DH_free(dh);
+                       dh = NULL;
+               }
+       }
+       return dh;
+}
+
+static DH *ssl_get_dh_3072(void)
+{
+       DH *dh = DH_new();
+       if (dh) {
+               dh->p = get_rfc3526_prime_3072(NULL);
+               /* See RFC 3526, Section 4 "3072-bit MODP Group"
+                  for the reason why we use 2 as a generator.
+                */
+               BN_dec2bn(&dh->g, "2");
+               if (!dh->p || !dh->g) {
+                       DH_free(dh);
+                       dh = NULL;
+               }
+       }
+       return dh;
+}
+
+static DH *ssl_get_dh_4096(void)
+{
+       DH *dh = DH_new();
+       if (dh) {
+               dh->p = get_rfc3526_prime_4096(NULL);
+               /* See RFC 3526, Section 5 "4096-bit MODP Group"
+                  for the reason why we use 2 as a generator.
+                */
+               BN_dec2bn(&dh->g, "2");
+               if (!dh->p || !dh->g) {
+                       DH_free(dh);
+                       dh = NULL;
+               }
+       }
+       return dh;
+}
+
+static DH *ssl_get_dh_6144(void)
+{
+       DH *dh = DH_new();
+       if (dh) {
+               dh->p = get_rfc3526_prime_6144(NULL);
+               /* See RFC 3526, Section 6 "6144-bit MODP Group"
+                  for the reason why we use 2 as a generator.
+                */
+               BN_dec2bn(&dh->g, "2");
+               if (!dh->p || !dh->g) {
+                       DH_free(dh);
+                       dh = NULL;
+               }
+       }
+       return dh;
+}
+
+static DH *ssl_get_dh_8192(void)
+{
+       DH *dh = DH_new();
+       if (dh) {
+               dh->p = get_rfc3526_prime_8192(NULL);
+               /* See RFC 3526, Section 7 "8192-bit MODP Group"
+                  for the reason why we use 2 as a generator.
+                */
+               BN_dec2bn(&dh->g, "2");
+               if (!dh->p || !dh->g) {
+                       DH_free(dh);
+                       dh = NULL;
+               }
+       }
+       return dh;
+}
+
+/* Returns Diffie-Hellman parameters matching the private key length */
+static DH *ssl_get_tmp_dh(SSL *ssl, int export, int keylen)
+{
+       DH *dh = NULL;
+       EVP_PKEY *pkey = SSL_get_privatekey(ssl);
+       int type = pkey ? EVP_PKEY_type(pkey->type) : EVP_PKEY_NONE;
+
+       if (type == EVP_PKEY_RSA || type == EVP_PKEY_DSA) {
+               keylen = EVP_PKEY_bits(pkey);
+       }
+
+       if (keylen >= 8192) {
+               dh = ssl_get_dh_8192();
+       }
+       else if (keylen >= 6144) {
+               dh = ssl_get_dh_6144();
+       }
+       else if (keylen >= 4096) {
+               dh = ssl_get_dh_4096();
+       }
+       else if (keylen >= 3072) {
+               dh = ssl_get_dh_3072();
+       }
+       else if (keylen >= 2048) {
+               dh = ssl_get_dh_2048();
+       }
+       else {
+               dh = ssl_get_dh_1024();
+       }
+
+       return dh;
+}
+
 /* Loads Diffie-Hellman parameter from a file. Returns 1 if loaded, else -1
    if an error occured, and 0 if parameter not found. */
-int ssl_sock_load_dh_params(SSL_CTX *ctx, const char *file)
+static int ssl_sock_load_dh_params(SSL_CTX *ctx, const char *file)
 {
        int ret = -1;
        BIO *in;
        DH *dh = NULL;
-       /* If not present, use parameters generated using 'openssl dhparam 1024 -C':
-        * -----BEGIN DH PARAMETERS-----
-        * MIGHAoGBAJJAJDXDoS5E03MNjnjK36eOL1tRqVa/9NuOVlI+lpXmPjJQbP65EvKn
-        * fSLnG7VMhoCJO4KtG88zf393ltP7loGB2bofcDSr+x+XsxBM8yA/Zj6BmQt+CQ9s
-        * TF7hoOV+wXTT6ErZ5y5qx9pq6hLfKXwTGFT78hrE6HnCO7xgtPdTAgEC
-        * -----END DH PARAMETERS-----
-       */
-       static const unsigned char dh1024_p[] = {
-               0x92, 0x40, 0x24, 0x35, 0xC3, 0xA1, 0x2E, 0x44, 0xD3, 0x73, 0x0D, 0x8E,
-               0x78, 0xCA, 0xDF, 0xA7, 0x8E, 0x2F, 0x5B, 0x51, 0xA9, 0x56, 0xBF, 0xF4,
-               0xDB, 0x8E, 0x56, 0x52, 0x3E, 0x96, 0x95, 0xE6, 0x3E, 0x32, 0x50, 0x6C,
-               0xFE, 0xB9, 0x12, 0xF2, 0xA7, 0x7D, 0x22, 0xE7, 0x1B, 0xB5, 0x4C, 0x86,
-               0x80, 0x89, 0x3B, 0x82, 0xAD, 0x1B, 0xCF, 0x33, 0x7F, 0x7F, 0x77, 0x96,
-               0xD3, 0xFB, 0x96, 0x81, 0x81, 0xD9, 0xBA, 0x1F, 0x70, 0x34, 0xAB, 0xFB,
-               0x1F, 0x97, 0xB3, 0x10, 0x4C, 0xF3, 0x20, 0x3F, 0x66, 0x3E, 0x81, 0x99,
-               0x0B, 0x7E, 0x09, 0x0F, 0x6C, 0x4C, 0x5E, 0xE1, 0xA0, 0xE5, 0x7E, 0xC1,
-               0x74, 0xD3, 0xE8, 0x4A, 0xD9, 0xE7, 0x2E, 0x6A, 0xC7, 0xDA, 0x6A, 0xEA,
-               0x12, 0xDF, 0x29, 0x7C, 0x13, 0x18, 0x54, 0xFB, 0xF2, 0x1A, 0xC4, 0xE8,
-               0x79, 0xC2, 0x3B, 0xBC, 0x60, 0xB4, 0xF7, 0x53,
-       };
-       static const unsigned char dh1024_g[] = {
-               0x02,
-       };
 
        in = BIO_new(BIO_s_file());
        if (in == NULL)
@@ -309,28 +422,17 @@ int ssl_sock_load_dh_params(SSL_CTX *ctx, const char *file)
                goto end;
 
        dh = PEM_read_bio_DHparams(in, NULL, ctx->default_passwd_callback, ctx->default_passwd_callback_userdata);
-       if (!dh) {
+       if (dh) {
+               ret = 1;
+               SSL_CTX_set_tmp_dh(ctx, dh);
+       }
+       else {
                /* Clear openssl global errors stack */
                ERR_clear_error();
 
-               dh = DH_new();
-               if (dh == NULL)
-                       goto end;
-
-               dh->p = BN_bin2bn(dh1024_p, sizeof(dh1024_p), NULL);
-               if (dh->p == NULL)
-                       goto end;
-
-               dh->g = BN_bin2bn(dh1024_g, sizeof(dh1024_g), NULL);
-               if (dh->g == NULL)
-                       goto end;
-
+               SSL_CTX_set_tmp_dh_callback(ctx, ssl_get_tmp_dh);
                ret = 0; /* DH params not found */
        }
-       else
-               ret = 1;
-
-       SSL_CTX_set_tmp_dh(ctx, dh);
 
 end:
        if (dh)