diff mbox series

[Openvpn-devel,v2] Restrict access to the service pipe to SYSTEM and owner

Message ID 20251124165353.14923-1-gert@greenie.muc.de
State New
Headers
Series [Openvpn-devel,v2] Restrict access to the service pipe to SYSTEM and owner |

Commit Message

Gert Doering Nov. 24, 2025, 4:53 p.m. UTC 
  From: Selva Nair <selva.nair@gmail.com>

Access is restricted to SYSTEM and pipe client user
(the user starting openvpn.exe). The default is
full access to Administrtors, owner, and read access
to everyone. This hardens the pipe further.

Change-Id: I8aa1cf1585e2320fca9329bdd0227976606fe71e
Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1397
---

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/+/1397
This mail reflects revision 2 of this Change.

Acked-by according to Gerrit (reflected above):
Gert Doering <gert@greenie.muc.de>

Comments

Gert Doering Nov. 24, 2025, 5:56 p.m. UTC | #1 
This sort of windows stuff is somewhat beyond my understanding, but
"it looks good and useful" - and Lev has actually understood & tested
it, and +2'ed in gerrit (which gerrit then lost on pushing the v2 which
only changed a comment...).  Fixed here in the commit, recording Lev's ACK.

Test compiled on mingw/ubuntu24.04

Your patch has been applied to the master branch.

commit 0a429cb13557356ac14cc458de3b42e3e09f6c62
Author: Selva Nair
Date:   Mon Nov 24 17:53:47 2025 +0100

     Restrict access to the service pipe to SYSTEM and owner

     Signed-off-by: Selva Nair <selva.nair@gmail.com>
     Acked-by: Lev Stipakov <lstipakov@gmail.com>
     Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1397
     Message-Id: <20251124165353.14923-1-gert@greenie.muc.de>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg34640.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering
diff mbox series

Patch

diff --git a/src/openvpnserv/interactive.c b/src/openvpnserv/interactive.c
index 7a0a075..4583077 100644
--- a/src/openvpnserv/interactive.c
+++ b/src/openvpnserv/interactive.c
@@ -3418,9 +3418,26 @@ 
              GetCurrentThreadId(), pipe_uuid_str);
     RpcStringFree(&pipe_uuid_str);
 
+    /* make a security descriptor for the named pipe with access
+     * restricted to the user and SYSTEM
+     */
+
+    SECURITY_ATTRIBUTES sa;
+    PSECURITY_DESCRIPTOR pSD = NULL;
+    LPCWSTR szSDDL = L"D:(A;;GA;;;SY)(A;;GA;;;OW)";
+    if (!ConvertStringSecurityDescriptorToSecurityDescriptorW(
+            szSDDL, SDDL_REVISION_1, &pSD, NULL))
+    {
+        ReturnLastError(pipe, L"ConvertSDDL");
+        goto out;
+    }
+    sa.nLength = sizeof(sa);
+    sa.lpSecurityDescriptor = pSD;
+    sa.bInheritHandle = FALSE;
+
     ovpn_pipe = CreateNamedPipe(
         ovpn_pipe_name, PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE | FILE_FLAG_OVERLAPPED,
-        PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT | PIPE_REJECT_REMOTE_CLIENTS, 1, 128, 128, 0, NULL);
+        PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT | PIPE_REJECT_REMOTE_CLIENTS, 1, 128, 128, 0, &sa);
     if (ovpn_pipe == INVALID_HANDLE_VALUE)
     {
         ReturnLastError(pipe, L"CreateNamedPipe");