wsd: to filter clientAddress before POST action.

Change-Id: I293580f041bc46b36c57f63fe4a2c0131763b3c1
Reviewed-on: https://gerrit.libreoffice.org/50977
Reviewed-by: pranavk <pranavk@collabora.co.uk>
Tested-by: pranavk <pranavk@collabora.co.uk>

loolwsd.xml.in

@@ -64,6 +64,9 @@
 
     <net desc="Network settings">
       <proto type="string" default="all" desc="Protocol to use IPv4, IPv6 or all for both">all</proto>
+      <post_allow desc="Allow/deny client IP address for POST(REST)." allow="true">
+        <host desc="Regex pattern of ip address to allow.">192\.168\.[0-9]{1,3}\.[0-9]{1,3}</host>
+      </post_allow>
     </net>
 
     <ssl desc="SSL settings">

net/ServerSocket.hpp

@@ -60,13 +60,22 @@ public:
     std::shared_ptr<Socket> accept()
     {
         // Accept a connection (if any) and set it to non-blocking.
-        // We don't care about the client's address, so ignored.
-        const int rc = ::accept4(getFD(), nullptr, nullptr, SOCK_NONBLOCK);
+        // There still need the client's address to filter request from POST(call from REST) here.
+        struct sockaddr_in clientInfo;
+        socklen_t addrlen = sizeof(struct sockaddr_in);
+        const int rc = ::accept4(getFD(), (struct sockaddr *)&clientInfo, &addrlen, SOCK_NONBLOCK);
         LOG_DBG("Accepted socket #" << rc << ", creating socket object.");
         try
         {
             // Create a socket object using the factory.
-            return rc != -1 ? _sockFactory->create(rc) : std::shared_ptr<Socket>(nullptr);
+            if (rc != -1)
+            {
+                std::string ip = inet_ntoa(clientInfo.sin_addr);
+                std::shared_ptr<Socket> _socket = _sockFactory->create(rc);
+                _socket->_clientAddress = ip;
+                return _socket;
+            }
+            return std::shared_ptr<Socket>(nullptr);
         }
         catch (const std::exception& ex)
         {

net/Socket.hpp

@@ -95,6 +95,7 @@ public:
     static const int DefaultSendBufferSize = 16 * 1024;
     static const int MaximumSendBufferSize = 128 * 1024;
     static std::atomic<bool> InhibitThreadChecks;
+    std::string _clientAddress;
 
     enum Type { IPv4, IPv6, All };
 
@@ -838,6 +839,11 @@ public:
         recv = _bytesRecvd;
     }
 
+    const std::string clientAddress()
+    {
+        return _clientAddress;
+    }
+
 protected:
 
     /// Called when a polling event is received.

wsd/LOOLWSD.cpp

@@ -1877,8 +1877,42 @@ private:
                 if (!(request.find("Upgrade") != request.end() && Poco::icompare(request["Upgrade"], "websocket") == 0) &&
                     reqPathTokens.count() > 0 && reqPathTokens[0] == "lool")
                 {
-                    // All post requests have url prefix 'lool'.
-                    handlePostRequest(request, message, disposition);
+                    // allow/deny for POST
+                    const auto& app = Poco::Util::Application::instance();
+                    Util::RegexListMatcher hosts;
+                    // Parse the host allow settings.
+                    for (size_t i = 0; ; ++i)
+                    {
+                        const std::string path = "post_allow.host[" + std::to_string(i) + "]";
+                        const auto host = app.config().getString(path, "");
+                        if (!host.empty())
+                        {
+                            LOG_INF("Adding trusted POST_ALLOW host: [" << host << "].");
+                            hosts.allow(host);
+                        }
+                        else if (!app.config().has(path))
+                        {
+                            break;
+                        }
+                    }
+                    if (!hosts.match(socket->clientAddress()))
+                    {
+                        LOG_ERR("client address DENY: " << socket->clientAddress().c_str());
+
+                        std::ostringstream oss;
+                        oss << "HTTP/1.1 403\r\n"
+                            << "Date: " << Poco::DateTimeFormatter::format(Poco::Timestamp(), Poco::DateTimeFormat::HTTP_FORMAT) << "\r\n"
+                            << "User-Agent: " << HTTP_AGENT_STRING << "\r\n"
+                            << "Content-Length: 0\r\n"
+                            << "\r\n";
+                        socket->send(oss.str());
+                        socket->shutdown();
+                    }
+                    else
+                    {
+                        // All post requests have url prefix 'lool'.
+                        handlePostRequest(request, message, disposition);
+                    }
                 }
                 else if (reqPathTokens.count() > 2 && reqPathTokens[0] == "lool" && reqPathTokens[2] == "ws" &&
                          request.find("Upgrade") != request.end() && Poco::icompare(request["Upgrade"], "websocket") == 0)