From 059e0fda44491f74a2dd51f595b82b5748b6cead Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <info@metux.net>
Date: Tue, 30 Jan 2024 15:05:37 +0100
Subject: [PATCH] Client: store auth credentials for later use

Store the client's auth credentials, so they can be used by extensions later.
---
 dix/dispatch.c      |  8 ++++++++
 include/dixstruct.h |  6 ++++++
 include/meson.build |  3 +++
 meson.build         | 10 ++++++++++
 os/connection.c     | 17 +++++++++++++++++
 5 files changed, 44 insertions(+)

diff --git a/dix/dispatch.c b/dix/dispatch.c
index eaac39b7c9..7aba3088b9 100644
--- a/dix/dispatch.c
+++ b/dix/dispatch.c
@@ -3549,6 +3549,14 @@ CloseDownClient(ClientPtr client)
             nextFreeClientID = client->index;
         clients[client->index] = NullClient;
         SmartLastClient = NullClient;
+
+#ifdef CONFIG_STORE_CLIENT_CREDS
+        if (client->authProto)
+            free(client->authProto);
+        if (client->authToken)
+            free(client->authToken);
+#endif /* CONFIG_STORE_CLIENT_CREDS */
+
         dixFreeObjectWithPrivates(client, PRIVATE_CLIENT);
 
         while (!clients[currentMaxClients - 1])
diff --git a/include/dixstruct.h b/include/dixstruct.h
index fb0ac14b89..64bdd7ca28 100644
--- a/include/dixstruct.h
+++ b/include/dixstruct.h
@@ -111,6 +111,12 @@ typedef struct _Client {
     DeviceIntPtr clientPtr;
     ClientIdPtr clientIds;
     int req_fds;
+
+#ifdef CONFIG_STORE_CLIENT_CREDS
+    /* auth credentials used to connect */
+    char *authProto;
+    char *authToken; // hex printed
+#endif /* CONFIG_STORE_CLIENT_CREDS */
 } ClientRec;
 
 static inline void
diff --git a/include/meson.build b/include/meson.build
index 236b953636..825db320f7 100644
--- a/include/meson.build
+++ b/include/meson.build
@@ -242,6 +242,9 @@ conf_data.set('XV', build_xv ? '1' : false)
 conf_data.set('XvExtension', build_xv ? '1' : false)
 conf_data.set('XvMCExtension', build_xvmc ? '1' : false)
 
+# enable auto-selected internal lib functions
+conf_data.set('CONFIG_STORE_CLIENT_CREDS', build_store_client_creds ? '1' : false)
+
 conf_data.set('HAVE_SHA1_IN_' + sha1.to_upper(), '1', description: 'Use @0@ SHA1 functions'.format(sha1))
 conf_data.set('HAVE_LIBUNWIND', get_option('libunwind'))
 
diff --git a/meson.build b/meson.build
index 1de3e2a4f4..e1e43d1605 100644
--- a/meson.build
+++ b/meson.build
@@ -114,8 +114,18 @@ if not libsystemd_daemon_dep.found()
     libsystemd_daemon_dep = dependency('libsystemd-daemon', required: false)
 endif
 
+#
+# internal lib components needed by other features
+# (will be enabled later, as needed)
+#
+
+# small hashtable implementation
 build_hashtable = false
 
+# storing client's auth credentials so they can later be retrieved by extensions
+build_store_client_creds = false
+
+
 # Resolve default values of some options
 xkb_dir = get_option('xkb_dir')
 if xkb_dir == ''
diff --git a/os/connection.c b/os/connection.c
index a3c8f2a998..6a5bc383dd 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -576,6 +576,23 @@ ClientAuthorized(ClientPtr client,
     priv->auth_id = auth_id;
     priv->conn_time = 0;
 
+#ifdef CONFIG_STORE_CLIENT_CREDS
+    {
+        /* store auth credentials for later use */
+        client->authProto = calloc(proto_n+1, 1);
+        memcpy(client->authProto, auth_proto, proto_n);
+
+        client->authToken = calloc(string_n*2+1, 1);
+        char *ptr = client->authToken;
+        for (int x=0; x<string_n; x++)
+        {
+            snprintf(ptr, 3, "%02hhx", auth_string[x]);
+            ptr++;
+            ptr++;
+        }
+    }
+#endif /* CONFIG_STORE_CLIENT_CREDS */
+
 #ifdef XDMCP
     /* indicate to Xdmcp protocol that we've opened new client */
     XdmcpOpenDisplay(priv->fd);