From 227fbc117d58a87465804f7b2a5cd95ef1b94da6 Mon Sep 17 00:00:00 2001 From: Arne Schwabe Date: Sun, 28 Mar 2021 14:02:41 +0200 Subject: [PATCH] Fix condition to generate session keys When OpenVPN sees a new (SSL) connection via HARD_RESET or SOFT_RESET with the same port/ip as an existing session, it will give it the slot of the renegotiation session (TM_UNTRUSTED). And when the authentication succeeds it will replace the current session. In the case of a SOFT_RESET this a renegotiation and we will generated data channel keys at the of key_method_2_write function as key-id > 0. For a HARD RESET the key-id is 0. Since we already have gone through connect stages and set context_auth to CAS_SUCCEEDED, we don't call all the connect stages again, and therefore also never call multi_client_generate_tls_keys for this session. This commit changes postponing the key generation to be done only if the multi_connect has not yet been finished. Patch V2: Explain better in the commit message why this change is done. This is "sort of" a backport of commit a005044be9ca, except that the master commit only got 1 of 3 hunks from the mailing list patch merged while release/2.5 needs all 3. So this is exactly the patch as it was sent to the list, URL below. Trac: #1316 Signed-off-by: Arne Schwabe Acked-by: Antonio Quartulli Acked-by: Gert Doering Message-Id: <20210328120241.27605-2-arne@rfc2549.org> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21873.html Signed-off-by: Gert Doering --- src/openvpn/ssl.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c index d7494c2b3e..8359748b9b 100644 --- a/src/openvpn/ssl.c +++ b/src/openvpn/ssl.c @@ -2295,7 +2295,8 @@ push_peer_info(struct buffer *buf, struct tls_session *session) * to the TLS control channel (cleartext). */ static bool -key_method_2_write(struct buffer *buf, struct tls_session *session) +key_method_2_write(struct buffer *buf, struct tls_multi *multi, + struct tls_session *session) { struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */ @@ -2386,12 +2387,17 @@ key_method_2_write(struct buffer *buf, struct tls_session *session) goto error; } - /* Generate tunnel keys if we're a TLS server. - * If we're a p2mp server and IV_NCP >= 2 is negotiated, the first key - * generation is postponed until after the pull/push, so we can process pushed - * cipher directives. + /* + * Generate tunnel keys if we're a TLS server. + * + * If we're a p2mp server to allow NCP, the first key + * generation is postponed until after the connect script finished and the + * NCP options can be processed. Since that always happens at after connect + * script options are available the CAS_SUCCEEDED status is identical to + * NCP options are processed and we have no extra state for NCP finished. */ - if (session->opt->server && !(session->opt->mode == MODE_SERVER && ks->key_id <= 0)) + if (session->opt->server && (session->opt->mode != MODE_SERVER + || multi->multi_state == CAS_SUCCEEDED)) { if (ks->authenticated > KS_AUTH_FALSE) { @@ -2847,7 +2853,7 @@ tls_process(struct tls_multi *multi, if (!buf->len && ((ks->state == S_START && !session->opt->server) || (ks->state == S_GOT_KEY && session->opt->server))) { - if (!key_method_2_write(buf, session)) + if (!key_method_2_write(buf, multi, session)) { goto error; }