Cherry-Pick "Fix condition to generate session keys"

Closes: #988478

2 files changed, 86 insertions, 0 deletions

diff --git a/debian/patches/Fix-condition-to-generate-session-keys.patch b/debian/patches/Fix-condition-to-generate-session-keys.patch
new file mode 100644
index 0000000..52fa248
--- /dev/null
+++ b/debian/patches/Fix-condition-to-generate-session-keys.patch
@@ -0,0 +1,85 @@
+From 227fbc117d58a87465804f7b2a5cd95ef1b94da6 Mon Sep 17 00:00:00 2001
+From: Arne Schwabe <arne@rfc2549.org>
+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 <arne@rfc2549.org>
+Acked-by: Antonio Quartulli <antonio@openvpn.net>
+Acked-by: Gert Doering <gert@greenie.muc.de>
+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 <gert@greenie.muc.de>
+---
+ 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;
+             }
diff --git a/debian/patches/series b/debian/patches/series
index 692c800..6bb0685 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -9,3 +9,4 @@ CVE-2020-15078-0.patch
 CVE-2020-15078-1.patch
 CVE-2020-15078-2.patch
 CVE-2020-15078-3.patch
+Fix-condition-to-generate-session-keys.patch