DH_get_1024_160() and DH_get_2048_224() return parameters from
RFC5114. Those parameters include primes with known small subgroups,
making them unsafe. Change the code to use parameters from
RFC 2409 and RFC 3526 instead (group 2 and 14 respectively).
This patch also adds automatic selection of 4096 bit params for 4096 bit
RSA keys
backport of
7646610
Signed-off-by: Hubert Kario <hkario@redhat.com>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/12160)
#ifndef OPENSSL_NO_DH
DH *ssl_get_auto_dh(SSL *s)
{
#ifndef OPENSSL_NO_DH
DH *ssl_get_auto_dh(SSL *s)
{
+ DH *dhp = NULL;
+ BIGNUM *p = NULL, *g = NULL;
- if (s->cert->dh_tmp_auto == 2)
- return DH_get_1024_160();
- if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aPSK)) {
- if (s->s3->tmp.new_cipher->strength_bits == 256)
- dh_secbits = 128;
- else
- dh_secbits = 80;
- } else {
- if (s->s3->tmp.cert == NULL)
- return NULL;
- dh_secbits = EVP_PKEY_security_bits(s->s3->tmp.cert->privatekey);
+ if (s->cert->dh_tmp_auto != 2) {
+ if (s->s3->tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aPSK)) {
+ if (s->s3->tmp.new_cipher->strength_bits == 256)
+ dh_secbits = 128;
+ else
+ dh_secbits = 80;
+ } else {
+ if (s->s3->tmp.cert == NULL)
+ return NULL;
+ dh_secbits = EVP_PKEY_security_bits(s->s3->tmp.cert->privatekey);
+ }
- if (dh_secbits >= 128) {
- DH *dhp = DH_new();
- BIGNUM *p, *g;
- if (dhp == NULL)
- return NULL;
- g = BN_new();
- if (g == NULL || !BN_set_word(g, 2)) {
- DH_free(dhp);
- BN_free(g);
- return NULL;
- }
- if (dh_secbits >= 192)
- p = BN_get_rfc3526_prime_8192(NULL);
- else
- p = BN_get_rfc3526_prime_3072(NULL);
- if (p == NULL || !DH_set0_pqg(dhp, p, NULL, g)) {
- DH_free(dhp);
- BN_free(p);
- BN_free(g);
- return NULL;
- }
- return dhp;
+ dhp = DH_new();
+ if (dhp == NULL)
+ return NULL;
+ g = BN_new();
+ if (g == NULL || !BN_set_word(g, 2)) {
+ DH_free(dhp);
+ BN_free(g);
+ return NULL;
+ }
+ if (dh_secbits >= 192)
+ p = BN_get_rfc3526_prime_8192(NULL);
+ else if (dh_secbits >= 152)
+ p = BN_get_rfc3526_prime_4096(NULL);
+ else if (dh_secbits >= 128)
+ p = BN_get_rfc3526_prime_3072(NULL);
+ else if (dh_secbits >= 112)
+ p = BN_get_rfc3526_prime_2048(NULL);
+ else
+ p = BN_get_rfc2409_prime_1024(NULL);
+ if (p == NULL || !DH_set0_pqg(dhp, p, NULL, g)) {
+ DH_free(dhp);
+ BN_free(p);
+ BN_free(g);
+ return NULL;
- if (dh_secbits >= 112)
- return DH_get_2048_224();
- return DH_get_1024_160();