Commit 09599b52 authored by Dr. Stephen Henson's avatar Dr. Stephen Henson
Browse files

Auto DH support. 

Add auto DH parameter support. This is roughly equivalent to the
ECDH auto curve selection but for DH. An application can just call

SSL_CTX_set_auto_dh(ctx, 1);

and appropriate DH parameters will be used based on the size of the
server key.

Unlike ECDH there is no way a peer can indicate the range of DH parameters
it supports. Some peers cannot handle DH keys larger that 1024 bits for
example. In this case if you call:

SSL_CTX_set_auto_dh(ctx, 2);

Only 1024 bit DH parameters will be used.

If the server key is 7680 bits or more in size then 8192 bit DH parameters
will be used: these will be *very* slow.

The old export ciphersuites aren't supported but those are very
insecure anyway.
parent 2514fa79

apps/s_server.c

+18 −31
Original line number Diff line number Diff line
@@ -218,7 +218,6 @@ static void init_session_cache_ctx(SSL_CTX *sctx); 
static void free_sessions(void);

#ifndef OPENSSL_NO_DH

static DH *load_dh_param(const char *dhfile);

static DH *get_dh512(void);

#endif



#ifdef MONOLITH
@@ -239,33 +238,6 @@ static int client_provided_client_authz = 0; 


#endif



#ifndef OPENSSL_NO_DH

static unsigned char dh512_p[]={

	0xDA,0x58,0x3C,0x16,0xD9,0x85,0x22,0x89,0xD0,0xE4,0xAF,0x75,

	0x6F,0x4C,0xCA,0x92,0xDD,0x4B,0xE5,0x33,0xB8,0x04,0xFB,0x0F,

	0xED,0x94,0xEF,0x9C,0x8A,0x44,0x03,0xED,0x57,0x46,0x50,0xD3,

	0x69,0x99,0xDB,0x29,0xD7,0x76,0x27,0x6B,0xA2,0xD3,0xD4,0x12,

	0xE2,0x18,0xF4,0xDD,0x1E,0x08,0x4C,0xF6,0xD8,0x00,0x3E,0x7C,

	0x47,0x74,0xE8,0x33,

	};

static unsigned char dh512_g[]={

	0x02,

	};



static DH *get_dh512(void)

	{

	DH *dh=NULL;



	if ((dh=DH_new()) == NULL) return(NULL);

	dh->p=BN_bin2bn(dh512_p,sizeof(dh512_p),NULL);

	dh->g=BN_bin2bn(dh512_g,sizeof(dh512_g),NULL);

	if ((dh->p == NULL) || (dh->g == NULL))

		return(NULL);

	return(dh);

	}

#endif





/* static int load_CA(SSL_CTX *ctx, char *file);*/



#undef BUFSIZZ
@@ -1931,11 +1903,18 @@ bad: 
		else

			{

			BIO_printf(bio_s_out,"Using default temp DH parameters\n");

			dh=get_dh512();

			}

		(void)BIO_flush(bio_s_out);



		SSL_CTX_set_tmp_dh(ctx,dh);

		if (dh == NULL)

			SSL_CTX_set_dh_auto(ctx, 1);

		else if (!SSL_CTX_set_tmp_dh(ctx,dh))

			{

			BIO_puts(bio_err, "Error setting temp DH parameters\n");

			ERR_print_errors(bio_err);

			DH_free(dh);

			goto end;

			}

#ifndef OPENSSL_NO_TLSEXT

		if (ctx2)

			{
@@ -1951,7 +1930,15 @@ bad: 
					dh = dh2;

					}

				}

			SSL_CTX_set_tmp_dh(ctx2,dh);

			if (dh == NULL)

				SSL_CTX_set_dh_auto(ctx2, 1);

			else if (!SSL_CTX_set_tmp_dh(ctx2,dh))

				{

				BIO_puts(bio_err, "Error setting temp DH parameters\n");

				ERR_print_errors(bio_err);

				DH_free(dh);

				goto end;

				}

			}

#endif

		DH_free(dh);

ssl/s3_lib.c

+6 −0
Original line number Diff line number Diff line
@@ -3254,6 +3254,9 @@ long ssl3_ctrl(SSL *s, int cmd, long larg, void *parg) 
		return(ret);

		}

		break;

	case SSL_CTRL_SET_DH_AUTO:

		s->cert->dh_tmp_auto = larg;

		return 1;

#endif

#ifndef OPENSSL_NO_ECDH

	case SSL_CTRL_SET_TMP_ECDH:
@@ -3759,6 +3762,9 @@ long ssl3_ctx_ctrl(SSL_CTX *ctx, int cmd, long larg, void *parg) 
		return(0);

		}

		break;

	case SSL_CTRL_SET_DH_AUTO:

		ctx->cert->dh_tmp_auto = larg;

		return 1;

#endif

#ifndef OPENSSL_NO_ECDH

	case SSL_CTRL_SET_TMP_ECDH:

ssl/s3_srvr.c

+15 −2
Original line number Diff line number Diff line
@@ -1679,6 +1679,17 @@ int ssl3_send_server_key_exchange(SSL *s) 
#ifndef OPENSSL_NO_DH

			if (type & SSL_kDHE)

			{

			if (s->cert->dh_tmp_auto)

				{

				dhp = ssl_get_auto_dh(s);

				if (dhp == NULL)

					{

					al=SSL_AD_INTERNAL_ERROR;

					SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_INTERNAL_ERROR);

					goto f_err;

					}

				}

			else

				dhp=cert->dh_tmp;

			if ((dhp == NULL) && (s->cert->dh_tmp_cb != NULL))

				dhp=s->cert->dh_tmp_cb(s,
@@ -1697,7 +1708,9 @@ int ssl3_send_server_key_exchange(SSL *s) 
				goto err;

				}



			if ((dh=DHparams_dup(dhp)) == NULL)

			if (s->cert->dh_tmp_auto)

				dh = dhp;

			else if ((dh=DHparams_dup(dhp)) == NULL)

				{

				SSLerr(SSL_F_SSL3_SEND_SERVER_KEY_EXCHANGE,ERR_R_DH_LIB);

				goto err;

ssl/ssl.h

+7 −0
Original line number Diff line number Diff line
@@ -1957,6 +1957,8 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION) 
#define SSL_CERT_SET_NEXT			2

#define SSL_CERT_SET_SERVER			3



#define SSL_CTRL_SET_DH_AUTO			118



#define DTLSv1_get_timeout(ssl, arg) \

	SSL_ctrl(ssl,DTLS_CTRL_GET_TIMEOUT,0, (void *)arg)

#define DTLSv1_handle_timeout(ssl) \
@@ -1982,6 +1984,11 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION) 
#define SSL_CTX_set_tmp_ecdh(ctx,ecdh) \

	SSL_CTX_ctrl(ctx,SSL_CTRL_SET_TMP_ECDH,0,(char *)ecdh)



#define SSL_CTX_set_dh_auto(ctx, onoff) \

	SSL_CTX_ctrl(ctx,SSL_CTRL_SET_DH_AUTO,onoff,NULL)

#define SSL_set_dh_auto(s, onoff) \

	SSL_ctrl(s,SSL_CTRL_SET_DH_AUTO,onoff,NULL)



#define SSL_need_tmp_RSA(ssl) \

	SSL_ctrl(ssl,SSL_CTRL_NEED_TMP_RSA,0,NULL)

#define SSL_set_tmp_rsa(ssl,rsa) \

ssl/ssl_cert.c

+1 −0
Original line number Diff line number Diff line
@@ -257,6 +257,7 @@ CERT *ssl_cert_dup(CERT *cert) 
			}

		}

	ret->dh_tmp_cb = cert->dh_tmp_cb;

	ret->dh_tmp_auto = cert->dh_tmp_auto;

#endif



#ifndef OPENSSL_NO_ECDH