From: Arne Schwabe <a...@rfc2549.org> With TLS 1.0 to 1.2, the used key agreement was depended on the certificates themselves. With TLS 1.3 is no longer the case but basically always X25519 was used. So this information has been very interesting so far. But with OpenSSL 3.5.0 and the new X25519MLKEM768 hybrid key agreement, the used key agreement group actually becomes interesting information.
This commit adds printing this information for OpenSSL 3.0.0+ and uses a compat version for OpenSSL 3.0-3.1 to avoid an additional ifdef in the code itself. Example output with ML-DSA-65 certificates on the server (client output): Control Channel: TLSv1.3, cipher TLSv1.3 TLS_AES_256_GCM_SHA384, peer certificate: 15616 bits ML-DSA-65, signature: id-ml-dsa-65, peer signing digest/type: mldsa65 id-ml-dsa-65, key agreement: X25519MLKEM768 with an secp384r1 certificate: Control Channel: TLSv1.3, cipher TLSv1.3 TLS_AES_256_GCM_SHA384, peer certificate: 384 bits ECsecp384r1, signature: ecdsa-with-SHA256, peer signing digest/type: ecdsa_secp384r1_sha384 ECDSA, key agreement: X25519MLKEM768 Change-Id: I90d54853fe1b1d820661cc2c099e07ec5d31ed05 Signed-off-by: Arne Schwabe <a...@rfc2549.org> Acked-by: Gert Doering <g...@greenie.muc.de> --- This change was reviewed on Gerrit and approved by at least one developer. I request to merge it to master. Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/938 This mail reflects revision 1 of this Change. Acked-by according to Gerrit (reflected above): Gert Doering <g...@greenie.muc.de> diff --git a/src/openvpn/openssl_compat.h b/src/openvpn/openssl_compat.h index e2bd9bf..bd6f09c 100644 --- a/src/openvpn/openssl_compat.h +++ b/src/openvpn/openssl_compat.h @@ -197,6 +197,13 @@ } #endif /* if OPENSSL_VERSION_NUMBER < 0x30500000 && (!defined(LIBRESSL_VERSION_NUMBER) || LIBRESSL_VERSION_NUMBER > 0x3050400fL) */ - +#if OPENSSL_VERSION_NUMBER < 0x30200000L && OPENSSL_VERSION_NUMBER >= 0x30000000L +static inline const char * +SSL_get0_group_name(SSL *s) +{ + int nid = SSL_get_negotiated_group(s); + return SSL_group_to_name(s, nid); +} +#endif #endif /* OPENSSL_COMPAT_H_ */ diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c index 23b0266..d1d5d3e 100644 --- a/src/openvpn/ssl_openssl.c +++ b/src/openvpn/ssl_openssl.c @@ -2486,7 +2486,21 @@ peer_sig, peer_sig_type); } - +#if OPENSSL_VERSION_NUMBER >= 0x30000000L +void +print_tls_key_agreement_group(SSL *ssl, char *buf, size_t buflen) +{ + const char *groupname = SSL_get0_group_name(ssl); + if (!groupname) + { + snprintf(buf, buflen, ", key agreement: (error fetching group)"); + } + else + { + snprintf(buf, buflen, ", key agreement: %s", groupname); + } +} +#endif /* ************************************** * @@ -2503,8 +2517,9 @@ char s2[256]; char s3[256]; char s4[256]; + char s5[256]; - s1[0] = s2[0] = s3[0] = s4[0] = 0; + s1[0] = s2[0] = s3[0] = s4[0] = s5[0] = 0; ciph = SSL_get_current_cipher(ks_ssl->ssl); snprintf(s1, sizeof(s1), "%s %s, cipher %s %s", prefix, @@ -2520,8 +2535,11 @@ } print_server_tempkey(ks_ssl->ssl, s3, sizeof(s3)); print_peer_signature(ks_ssl->ssl, s4, sizeof(s4)); +#if OPENSSL_VERSION_NUMBER >= 0x30000000L + print_tls_key_agreement_group(ks_ssl->ssl, s5, sizeof(s5)); +#endif - msg(D_HANDSHAKE, "%s%s%s%s", s1, s2, s3, s4); + msg(D_HANDSHAKE, "%s%s%s%s%s", s1, s2, s3, s4, s5); } void _______________________________________________ Openvpn-devel mailing list Openvpn-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openvpn-devel
