[Openvpn-devel] [PATCH v1] Fix logic when pushed cipher triggers tun reopen and ignore more options

[Gert D. <ge...@gr...>]

From: Arne Schwabe <ar...@rf...>

The logic was inverted. Only when link-mtu is used, pushing a cipher can
change the MTU and not the other way round. (found by zeropath)

Also ignore a few more options that should not trigger a reopen of tun
in push message.

Reported-By: co...@jo...
Found-By: Zeropath
Change-Id: I76eb584024610a6054a069340adbac988abf686c
Signed-off-by: Arne Schwabe <arn...@rf...>
Acked-by: Gert Doering <ge...@gr...>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1321
---

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/+/1321
This mail reflects revision 1 of this Change.

Signed-off-by line for the author was added as per our policy.

Acked-by according to Gerrit (reflected above):
Gert Doering <ge...@gr...>

        
diff --git a/src/openvpn/push.c b/src/openvpn/push.c
index 2c717c7..d7063e6 100644
--- a/src/openvpn/push.c
+++ b/src/openvpn/push.c
@@ -1025,15 +1025,25 @@
     char line[OPTION_PARM_SIZE];
     while (buf_parse(buf, ',', line, sizeof(line)))
     {
-        /* peer-id and auth-token might change on restart and this should not trigger reopening tun
+        /* peer-id and auth-token might change on restart and this should not
+         * trigger reopening tun
+         * Also other options that only affect the control channel should
+         * not trigger a reopen of the tun device
          */
-        if (strprefix(line, "peer-id ") || strprefix(line, "auth-token ")
-            || strprefix(line, "auth-token-user "))
+        if (strprefix(line, "peer-id ")
+            || strprefix(line, "auth-token ")
+            || strprefix(line, "auth-token-user")
+            || strprefix(line, "protocol-flags ")
+            || strprefix(line, "key-derivation ")
+            || strprefix(line, "explicit-exit-notify ")
+            || strprefix(line, "ping ")
+            || strprefix(line, "ping-restart ")
+            || strprefix(line, "ping-timer "))
         {
             continue;
         }
         /* tun reopen only needed if cipher change can change tun MTU */
-        if (strprefix(line, "cipher ") && !opt->ce.tun_mtu_defined)
+        if (strprefix(line, "cipher ") && opt->ce.tun_mtu_defined)
         {
             continue;
         }