summaryrefslogtreecommitdiffstats
path: root/channels/sshagent
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--channels/sshagent/CMakeLists.txt23
-rw-r--r--channels/sshagent/ChannelOptions.cmake12
-rw-r--r--channels/sshagent/client/CMakeLists.txt32
-rw-r--r--channels/sshagent/client/sshagent_main.c375
-rw-r--r--channels/sshagent/client/sshagent_main.h42
5 files changed, 484 insertions, 0 deletions
diff --git a/channels/sshagent/CMakeLists.txt b/channels/sshagent/CMakeLists.txt
new file mode 100644
index 0000000..71aab99
--- /dev/null
+++ b/channels/sshagent/CMakeLists.txt
@@ -0,0 +1,23 @@
+# FreeRDP: A Remote Desktop Protocol Implementation
+# FreeRDP cmake build script
+#
+# Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
+# Copyright 2017 Ben Cohen
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+define_channel("sshagent")
+
+if(WITH_CLIENT_CHANNELS)
+ add_channel_client(${MODULE_PREFIX} ${CHANNEL_NAME})
+endif()
diff --git a/channels/sshagent/ChannelOptions.cmake b/channels/sshagent/ChannelOptions.cmake
new file mode 100644
index 0000000..41b5a21
--- /dev/null
+++ b/channels/sshagent/ChannelOptions.cmake
@@ -0,0 +1,12 @@
+
+set(OPTION_DEFAULT OFF)
+set(OPTION_CLIENT_DEFAULT OFF)
+set(OPTION_SERVER_DEFAULT OFF)
+
+define_channel_options(NAME "sshagent" TYPE "dynamic"
+ DESCRIPTION "SSH Agent Forwarding (experimental)"
+ SPECIFICATIONS ""
+ DEFAULT ${OPTION_DEFAULT})
+
+define_channel_client_options(${OPTION_CLIENT_DEFAULT})
+
diff --git a/channels/sshagent/client/CMakeLists.txt b/channels/sshagent/client/CMakeLists.txt
new file mode 100644
index 0000000..daad106
--- /dev/null
+++ b/channels/sshagent/client/CMakeLists.txt
@@ -0,0 +1,32 @@
+# FreeRDP: A Remote Desktop Protocol Implementation
+# FreeRDP cmake build script
+#
+# Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
+# Copyright 2017 Ben Cohen
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+define_channel_client("sshagent")
+
+set(${MODULE_PREFIX}_SRCS
+ sshagent_main.c
+ sshagent_main.h
+)
+
+set(${MODULE_PREFIX}_LIBS
+ winpr
+)
+
+include_directories(..)
+
+add_channel_client_library(${MODULE_PREFIX} ${MODULE_NAME} ${CHANNEL_NAME} TRUE "DVCPluginEntry")
diff --git a/channels/sshagent/client/sshagent_main.c b/channels/sshagent/client/sshagent_main.c
new file mode 100644
index 0000000..9ee5102
--- /dev/null
+++ b/channels/sshagent/client/sshagent_main.c
@@ -0,0 +1,375 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Implementation
+ * SSH Agent Virtual Channel Extension
+ *
+ * Copyright 2013 Christian Hofstaedtler
+ * Copyright 2015 Thincast Technologies GmbH
+ * Copyright 2015 DI (FH) Martin Haimberger <martin.haimberger@thincast.com>
+ * Copyright 2017 Ben Cohen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * sshagent_main.c: DVC plugin to forward queries from RDP to the ssh-agent
+ *
+ * This relays data to and from an ssh-agent program equivalent running on the
+ * RDP server to an ssh-agent running locally. Unlike the normal ssh-agent,
+ * which sends data over an SSH channel, the data is send over an RDP dynamic
+ * virtual channel.
+ *
+ * protocol specification:
+ * Forward data verbatim over RDP dynamic virtual channel named "sshagent"
+ * between a ssh client on the xrdp server and the real ssh-agent where
+ * the RDP client is running. Each connection by a separate client to
+ * xrdp-ssh-agent gets a separate DVC invocation.
+ */
+
+#include <freerdp/config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <pwd.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <winpr/crt.h>
+#include <winpr/synch.h>
+#include <winpr/thread.h>
+#include <winpr/stream.h>
+
+#include "sshagent_main.h"
+
+#include <freerdp/freerdp.h>
+#include <freerdp/client/channels.h>
+#include <freerdp/channels/log.h>
+
+#define TAG CHANNELS_TAG("sshagent.client")
+
+typedef struct
+{
+ IWTSListenerCallback iface;
+
+ IWTSPlugin* plugin;
+ IWTSVirtualChannelManager* channel_mgr;
+
+ rdpContext* rdpcontext;
+ const char* agent_uds_path;
+} SSHAGENT_LISTENER_CALLBACK;
+
+typedef struct
+{
+ GENERIC_CHANNEL_CALLBACK generic;
+
+ rdpContext* rdpcontext;
+ int agent_fd;
+ HANDLE thread;
+ CRITICAL_SECTION lock;
+} SSHAGENT_CHANNEL_CALLBACK;
+
+typedef struct
+{
+ IWTSPlugin iface;
+
+ SSHAGENT_LISTENER_CALLBACK* listener_callback;
+
+ rdpContext* rdpcontext;
+} SSHAGENT_PLUGIN;
+
+/**
+ * Function to open the connection to the sshagent
+ *
+ * @return The fd on success, otherwise -1
+ */
+static int connect_to_sshagent(const char* udspath)
+{
+ int agent_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+
+ if (agent_fd == -1)
+ {
+ WLog_ERR(TAG, "Can't open Unix domain socket!");
+ return -1;
+ }
+
+ struct sockaddr_un addr = { 0 };
+
+ addr.sun_family = AF_UNIX;
+
+ strncpy(addr.sun_path, udspath, sizeof(addr.sun_path) - 1);
+
+ int rc = connect(agent_fd, (struct sockaddr*)&addr, sizeof(addr));
+
+ if (rc != 0)
+ {
+ WLog_ERR(TAG, "Can't connect to Unix domain socket \"%s\"!", udspath);
+ close(agent_fd);
+ return -1;
+ }
+
+ return agent_fd;
+}
+
+/**
+ * Entry point for thread to read from the ssh-agent socket and forward
+ * the data to RDP
+ *
+ * @return NULL
+ */
+static DWORD WINAPI sshagent_read_thread(LPVOID data)
+{
+ SSHAGENT_CHANNEL_CALLBACK* callback = (SSHAGENT_CHANNEL_CALLBACK*)data;
+ BYTE buffer[4096];
+ int going = 1;
+ UINT status = CHANNEL_RC_OK;
+
+ while (going)
+ {
+ int bytes_read = read(callback->agent_fd, buffer, sizeof(buffer));
+
+ if (bytes_read == 0)
+ {
+ /* Socket closed cleanly at other end */
+ going = 0;
+ }
+ else if (bytes_read < 0)
+ {
+ if (errno != EINTR)
+ {
+ WLog_ERR(TAG, "Error reading from sshagent, errno=%d", errno);
+ status = ERROR_READ_FAULT;
+ going = 0;
+ }
+ }
+ else
+ {
+ /* Something read: forward to virtual channel */
+ IWTSVirtualChannel* channel = callback->generic.channel;
+ status = channel->Write(channel, bytes_read, buffer, NULL);
+
+ if (status != CHANNEL_RC_OK)
+ {
+ going = 0;
+ }
+ }
+ }
+
+ close(callback->agent_fd);
+
+ if (status != CHANNEL_RC_OK)
+ setChannelError(callback->rdpcontext, status, "sshagent_read_thread reported an error");
+
+ ExitThread(status);
+ return status;
+}
+
+/**
+ * Callback for data received from the RDP server; forward this to ssh-agent
+ *
+ * @return 0 on success, otherwise a Win32 error code
+ */
+static UINT sshagent_on_data_received(IWTSVirtualChannelCallback* pChannelCallback, wStream* data)
+{
+ SSHAGENT_CHANNEL_CALLBACK* callback = (SSHAGENT_CHANNEL_CALLBACK*)pChannelCallback;
+ BYTE* pBuffer = Stream_Pointer(data);
+ UINT32 cbSize = Stream_GetRemainingLength(data);
+ BYTE* pos = pBuffer;
+ /* Forward what we have received to the ssh agent */
+ UINT32 bytes_to_write = cbSize;
+ errno = 0;
+
+ while (bytes_to_write > 0)
+ {
+ int bytes_written = write(callback->agent_fd, pos, bytes_to_write);
+
+ if (bytes_written < 0)
+ {
+ if (errno != EINTR)
+ {
+ WLog_ERR(TAG, "Error writing to sshagent, errno=%d", errno);
+ return ERROR_WRITE_FAULT;
+ }
+ }
+ else
+ {
+ bytes_to_write -= bytes_written;
+ pos += bytes_written;
+ }
+ }
+
+ /* Consume stream */
+ Stream_Seek(data, cbSize);
+ return CHANNEL_RC_OK;
+}
+
+/**
+ * Callback for when the virtual channel is closed
+ *
+ * @return 0 on success, otherwise a Win32 error code
+ */
+static UINT sshagent_on_close(IWTSVirtualChannelCallback* pChannelCallback)
+{
+ SSHAGENT_CHANNEL_CALLBACK* callback = (SSHAGENT_CHANNEL_CALLBACK*)pChannelCallback;
+ /* Call shutdown() to wake up the read() in sshagent_read_thread(). */
+ shutdown(callback->agent_fd, SHUT_RDWR);
+ EnterCriticalSection(&callback->lock);
+
+ if (WaitForSingleObject(callback->thread, INFINITE) == WAIT_FAILED)
+ {
+ UINT error = GetLastError();
+ WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "!", error);
+ return error;
+ }
+
+ CloseHandle(callback->thread);
+ LeaveCriticalSection(&callback->lock);
+ DeleteCriticalSection(&callback->lock);
+ free(callback);
+ return CHANNEL_RC_OK;
+}
+
+/**
+ * Callback for when a new virtual channel is opened
+ *
+ * @return 0 on success, otherwise a Win32 error code
+ */
+static UINT sshagent_on_new_channel_connection(IWTSListenerCallback* pListenerCallback,
+ IWTSVirtualChannel* pChannel, BYTE* Data,
+ BOOL* pbAccept,
+ IWTSVirtualChannelCallback** ppCallback)
+{
+ SSHAGENT_CHANNEL_CALLBACK* callback;
+ GENERIC_CHANNEL_CALLBACK* generic;
+ SSHAGENT_LISTENER_CALLBACK* listener_callback = (SSHAGENT_LISTENER_CALLBACK*)pListenerCallback;
+ callback = (SSHAGENT_CHANNEL_CALLBACK*)calloc(1, sizeof(SSHAGENT_CHANNEL_CALLBACK));
+
+ if (!callback)
+ {
+ WLog_ERR(TAG, "calloc failed!");
+ return CHANNEL_RC_NO_MEMORY;
+ }
+
+ /* Now open a connection to the local ssh-agent. Do this for each
+ * connection to the plugin in case we mess up the agent session. */
+ callback->agent_fd = connect_to_sshagent(listener_callback->agent_uds_path);
+
+ if (callback->agent_fd == -1)
+ {
+ free(callback);
+ return CHANNEL_RC_INITIALIZATION_ERROR;
+ }
+
+ InitializeCriticalSection(&callback->lock);
+ generic = &callback->generic;
+ generic->iface.OnDataReceived = sshagent_on_data_received;
+ generic->iface.OnClose = sshagent_on_close;
+ generic->plugin = listener_callback->plugin;
+ generic->channel_mgr = listener_callback->channel_mgr;
+ generic->channel = pChannel;
+ callback->rdpcontext = listener_callback->rdpcontext;
+ callback->thread = CreateThread(NULL, 0, sshagent_read_thread, (void*)callback, 0, NULL);
+
+ if (!callback->thread)
+ {
+ WLog_ERR(TAG, "CreateThread failed!");
+ DeleteCriticalSection(&callback->lock);
+ free(callback);
+ return CHANNEL_RC_INITIALIZATION_ERROR;
+ }
+
+ *ppCallback = (IWTSVirtualChannelCallback*)callback;
+ return CHANNEL_RC_OK;
+}
+
+/**
+ * Callback for when the plugin is initialised
+ *
+ * @return 0 on success, otherwise a Win32 error code
+ */
+static UINT sshagent_plugin_initialize(IWTSPlugin* pPlugin, IWTSVirtualChannelManager* pChannelMgr)
+{
+ SSHAGENT_PLUGIN* sshagent = (SSHAGENT_PLUGIN*)pPlugin;
+ sshagent->listener_callback =
+ (SSHAGENT_LISTENER_CALLBACK*)calloc(1, sizeof(SSHAGENT_LISTENER_CALLBACK));
+
+ if (!sshagent->listener_callback)
+ {
+ WLog_ERR(TAG, "calloc failed!");
+ return CHANNEL_RC_NO_MEMORY;
+ }
+
+ sshagent->listener_callback->rdpcontext = sshagent->rdpcontext;
+ sshagent->listener_callback->iface.OnNewChannelConnection = sshagent_on_new_channel_connection;
+ sshagent->listener_callback->plugin = pPlugin;
+ sshagent->listener_callback->channel_mgr = pChannelMgr;
+ sshagent->listener_callback->agent_uds_path = getenv("SSH_AUTH_SOCK");
+
+ if (sshagent->listener_callback->agent_uds_path == NULL)
+ {
+ WLog_ERR(TAG, "Environment variable $SSH_AUTH_SOCK undefined!");
+ free(sshagent->listener_callback);
+ sshagent->listener_callback = NULL;
+ return CHANNEL_RC_INITIALIZATION_ERROR;
+ }
+
+ return pChannelMgr->CreateListener(pChannelMgr, "SSHAGENT", 0,
+ (IWTSListenerCallback*)sshagent->listener_callback, NULL);
+}
+
+/**
+ * Callback for when the plugin is terminated
+ *
+ * @return 0 on success, otherwise a Win32 error code
+ */
+static UINT sshagent_plugin_terminated(IWTSPlugin* pPlugin)
+{
+ SSHAGENT_PLUGIN* sshagent = (SSHAGENT_PLUGIN*)pPlugin;
+ free(sshagent);
+ return CHANNEL_RC_OK;
+}
+
+/**
+ * Main entry point for sshagent DVC plugin
+ *
+ * @return 0 on success, otherwise a Win32 error code
+ */
+FREERDP_ENTRY_POINT(UINT sshagent_DVCPluginEntry(IDRDYNVC_ENTRY_POINTS* pEntryPoints))
+{
+ UINT status = CHANNEL_RC_OK;
+ SSHAGENT_PLUGIN* sshagent;
+ sshagent = (SSHAGENT_PLUGIN*)pEntryPoints->GetPlugin(pEntryPoints, "sshagent");
+
+ if (!sshagent)
+ {
+ sshagent = (SSHAGENT_PLUGIN*)calloc(1, sizeof(SSHAGENT_PLUGIN));
+
+ if (!sshagent)
+ {
+ WLog_ERR(TAG, "calloc failed!");
+ return CHANNEL_RC_NO_MEMORY;
+ }
+
+ sshagent->iface.Initialize = sshagent_plugin_initialize;
+ sshagent->iface.Connected = NULL;
+ sshagent->iface.Disconnected = NULL;
+ sshagent->iface.Terminated = sshagent_plugin_terminated;
+ sshagent->rdpcontext = pEntryPoints->GetRdpContext(pEntryPoints);
+ status = pEntryPoints->RegisterPlugin(pEntryPoints, "sshagent", &sshagent->iface);
+ }
+
+ return status;
+}
+
+/* vim: set sw=8:ts=8:noet: */
diff --git a/channels/sshagent/client/sshagent_main.h b/channels/sshagent/client/sshagent_main.h
new file mode 100644
index 0000000..1fcc214
--- /dev/null
+++ b/channels/sshagent/client/sshagent_main.h
@@ -0,0 +1,42 @@
+/**
+ * FreeRDP: A Remote Desktop Protocol Implementation
+ * SSH Agent Virtual Channel Extension
+ *
+ * Copyright 2013 Christian Hofstaedtler
+ * Copyright 2017 Ben Cohen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SSHAGENT_MAIN_H
+#define SSHAGENT_MAIN_H
+
+#include <freerdp/config.h>
+
+#include <winpr/stream.h>
+
+#include <freerdp/svc.h>
+#include <freerdp/addin.h>
+#include <freerdp/channels/log.h>
+
+#define DVC_TAG CHANNELS_TAG("sshagent.client")
+#ifdef WITH_DEBUG_SSHAGENT
+#define DEBUG_SSHAGENT(...) WLog_DBG(DVC_TAG, __VA_ARGS__)
+#else
+#define DEBUG_SSHAGENT(...) \
+ do \
+ { \
+ } while (0)
+#endif
+
+#endif /* SSHAGENT_MAIN_H */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-27 18:21:30 +0000