controlscript must be located in plugin_dir

common/utils/string_utils.cpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2024  Johannes Pohl
+    Copyright (C) 2014-2025  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -105,6 +105,31 @@ std::string trim_copy(const std::string& s)
     return trim(str);
 }
 
+
+std::string urlEncode(const std::string& str)
+{
+    std::ostringstream os;
+    for (std::string::const_iterator ci = str.begin(); ci != str.end(); ++ci)
+    {
+        if ((*ci >= 'a' && *ci <= 'z') || (*ci >= 'A' && *ci <= 'Z') || (*ci >= '0' && *ci <= '9'))
+        { // allowed
+            os << *ci;
+        }
+        else if (*ci == ' ')
+        {
+            os << '+';
+        }
+        else
+        {
+            auto toHex = [](unsigned char x) { return static_cast<unsigned char>(x + (x > 9 ? ('A' - 10) : '0')); };
+            os << '%' << toHex(*ci >> 4) << toHex(*ci % 16);
+        }
+    }
+
+    return os.str();
+}
+
+
 // decode %xx to char
 std::string uriDecode(const std::string& src)
 {

common/utils/string_utils.hpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2024  Johannes Pohl
+    Copyright (C) 2014-2025  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -54,6 +54,9 @@ std::string trim_copy(const std::string& s);
 /// decode %xx to char
 std::string uriDecode(const std::string& src);
 
+/// @return uri encoded version of @p str
+std::string urlEncode(const std::string& str);
+
 /// Split string @p s at @p delim into @p left and @p right
 void split_left(const std::string& s, char delim, std::string& left, std::string& right);
 

doc/json_rpc_api/control.md

@@ -485,7 +485,7 @@ See [Plugin.Stream.Player.SetProperty](stream_plugin.md#pluginstreamplayersetpro
 ### Stream.AddStream
 
 Note: For security purposes, the RPC interface allows only adding streams of these types: `pipe`, `file`, `tcp`, `alsa`, `jack` and `meta`.
-It is also not allowed to set the `controlscript` query parameter of `streamUri`.
+The optional`controlscript` of the `streamUri` must be located in `[stream] plugin_dir` (configured in `snapserver.conf`, default `/usr/share/snapserver/plug-ins`), can be an absolute or relative path.
 
 #### Request
 

server/control_requests.cpp

@@ -22,11 +22,13 @@
 // local headers
 #include "common/aixlog.hpp"
 #include "common/message/server_settings.hpp"
+#include "jsonrpcpp.hpp"
 #include "server.hpp"
 
 // 3rd party headers
 
 // standard headers
+#include <filesystem>
 #include <memory>
 #include <tuple>
 
@@ -692,18 +694,35 @@ void StreamAddRequest::execute(const jsonrpcpp::request_ptr& request, AuthInfo&
 
     // Don't allow adding streams that start a user defined process: CVE-2023-36177
     static constexpr std::array whitelist{"pipe", "file", "tcp", "alsa", "jack", "meta"};
-    const std::string stream_uri = request->params().get("streamUri");
-    const StreamUri parsedUri(stream_uri);
+    std::string stream_uri = request->params().get("streamUri");
+    StreamUri parsed_uri(stream_uri);
 
-    if (std::find(whitelist.begin(), whitelist.end(), parsedUri.scheme) == whitelist.end())
-        throw jsonrpcpp::InvalidParamsException("Adding '" + parsedUri.scheme + "' streams is not allowed", request->id());
+    if (std::find(whitelist.begin(), whitelist.end(), parsed_uri.scheme) == whitelist.end())
+        throw jsonrpcpp::InvalidParamsException("Adding '" + parsed_uri.scheme + "' streams is not allowed", request->id());
 
-    // Don't allow settings the controlscript streamUri property
-    if (!parsedUri.getQuery("controlscript").empty())
-        throw jsonrpcpp::InvalidParamsException("No 'controlscript' streamUri property allowed", request->id());
+    std::filesystem::path script = parsed_uri.getQuery("controlscript");
+    if (!script.empty())
+    {
+        // script must be located in the [stream] plugin_dir
+        std::filesystem::path plugin_dir = getSettings().stream.plugin_dir;
+        // if script file name is relative, prepend the plugin_dir
+        if (!script.is_absolute())
+            script = plugin_dir / script;
+        // convert to normalized absolute path
+        script = std::filesystem::weakly_canonical(script);
+        LOG(DEBUG, LOG_TAG) << "controlscript: " << script.native() << "\n";
+        // check if script is directly located in plugin_dir
+        if (script.parent_path() != plugin_dir)
+            throw jsonrpcpp::InvalidParamsException("controlscript must be located in '" + plugin_dir.native() + "'");
+        if (!std::filesystem::exists(script))
+            throw jsonrpcpp::InvalidParamsException("controlscript '" + script.native() + "' does not exist");
+        parsed_uri.query["controlscript"] = script;
+        LOG(DEBUG, LOG_TAG) << "Raw stream uri: " << stream_uri << "\n";
+        stream_uri = parsed_uri.toString();
+    }
 
     std::ignore = authinfo;
-    LOG(INFO, LOG_TAG) << "Stream.AddStream(" << request->params().get("streamUri") << ")\n";
+    LOG(INFO, LOG_TAG) << "Stream.AddStream(" << stream_uri << ")\n";
 
     // Add stream
     PcmStreamPtr stream = getStreamManager().addStream(stream_uri);

server/etc/snapserver.conf

@@ -166,6 +166,9 @@ doc_root = /usr/share/snapserver/snapweb
 # meta: meta:///<name of source#1>/<name of source#2>/.../<name of source#N>?name=<name>
 source = pipe:///tmp/snapfifo?name=default
 
+# Plugin directory, containing scripts, referred by "controlscript"
+# plugin_dir = /usr/share/snapserver/plug-ins
+
 # Default sample format: <sample rate>:<bits per sample>:<channels>
 #sampleformat = 48000:16:2
 

server/server_settings.hpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2024  Johannes Pohl
+    Copyright (C) 2014-2025  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -92,6 +92,7 @@ struct ServerSettings
     struct Stream
     {
         size_t port{1704};
+        std::filesystem::path plugin_dir{"/usr/share/snapserver/plug-ins"};
         std::vector<std::string> sources;
         std::string codec{"flac"};
         int32_t bufferMs{1000};

server/snapserver.cpp

@@ -113,6 +113,7 @@ int main(int argc, char* argv[])
                                                            settings.tcp.bind_to_address.front(), &settings.tcp.bind_to_address[0]);
 
         // stream settings
+        conf.add<Value<std::filesystem::path>>("", "stream.plugin_dir", "stream plugin directory", settings.stream.plugin_dir, &settings.stream.plugin_dir);
         auto stream_bind_to_address = conf.add<Value<string>>("", "stream.bind_to_address", "address for the server to listen on",
                                                               settings.stream.bind_to_address.front(), &settings.stream.bind_to_address[0]);
         conf.add<Value<size_t>>("", "stream.port", "which port the server should listen on", settings.stream.port, &settings.stream.port);
@@ -296,6 +297,8 @@ int main(int argc, char* argv[])
         if (!streamValue->is_set() && !sourceValue->is_set())
             settings.stream.sources.push_back(sourceValue->value());
 
+        settings.stream.plugin_dir = std::filesystem::weakly_canonical(settings.stream.plugin_dir);
+        LOG(INFO, LOG_TAG) << "Stream plugin directory: " << settings.stream.plugin_dir << "\n";
         for (size_t n = 0; n < streamValue->count(); ++n)
         {
             LOG(INFO, LOG_TAG) << "Adding stream: " << streamValue->value(n) << "\n";

server/streamreader/pcm_stream.cpp

@@ -72,7 +72,7 @@ PcmStream::PcmStream(PcmStream::Listener* pcmListener, boost::asio::io_context&
         std::string params;
         if (uri_.query.find(kControlScriptParams) != uri_.query.end())
             params = uri_.query[kControlScriptParams];
-        stream_ctrl_ = std::make_unique<ScriptStreamControl>(strand_, uri_.query[kControlScript], params);
+        stream_ctrl_ = std::make_unique<ScriptStreamControl>(strand_, server_settings_.stream.plugin_dir, uri_.query[kControlScript], std::move(params));
     }
 
     if (uri_.query.find(kUriChunkMs) != uri_.query.end())

server/streamreader/stream_control.cpp

@@ -129,15 +129,15 @@ void StreamControl::onLog(std::string message)
 
 
 
-ScriptStreamControl::ScriptStreamControl(const boost::asio::any_io_executor& executor, const std::string& script, const std::string& params)
-    : StreamControl(executor), script_(script), params_(params)
+ScriptStreamControl::ScriptStreamControl(const boost::asio::any_io_executor& executor, const std::filesystem::path& plugin_dir, std::string script,
+                                         std::string params)
+    : StreamControl(executor), script_(std::move(script)), params_(std::move(params))
 {
     namespace fs = utils::file;
     if (!fs::exists(script_))
     {
-        std::string plugin_path = "/usr/share/snapserver/plug-ins/";
-        if (fs::exists(plugin_path + script_))
-            script_ = plugin_path + script_;
+        if (fs::exists(plugin_dir / script_))
+            script_ = plugin_dir / script_;
         else
             throw SnapException("Control script not found: \"" + script_ + "\"");
     }

server/streamreader/stream_control.hpp

@@ -28,6 +28,7 @@
 #include <boost/process.hpp>
 
 // standard headers
+#include <filesystem>
 #include <map>
 #include <string>
 
@@ -78,10 +79,10 @@ private:
 class ScriptStreamControl : public StreamControl
 {
 public:
-    ScriptStreamControl(const boost::asio::any_io_executor& executor, const std::string& script, const std::string& params);
+    ScriptStreamControl(const boost::asio::any_io_executor& executor, const std::filesystem::path& plugin_dir, std::string script, std::string params);
     virtual ~ScriptStreamControl() = default;
 
-protected:
+private:
     /// Send a message to stdin of the process
     void doCommand(const jsonrpcpp::Request& request) override;
     void doStart(const std::string& stream_id, const ServerSettings& server_setttings) override;

server/streamreader/stream_uri.cpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2024  Johannes Pohl
+    Copyright (C) 2014-2025  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -31,6 +31,8 @@
 using namespace std;
 namespace strutils = utils::string;
 
+static constexpr auto LOG_TAG = "StreamUri";
+
 namespace streamreader
 {
 
@@ -40,34 +42,39 @@ StreamUri::StreamUri(const std::string& uri)
 }
 
 
-void StreamUri::parse(const std::string& streamUri)
+void StreamUri::parse(const std::string& stream_uri)
 {
     // https://en.wikipedia.org/wiki/Uniform_Resource_Identifier
     // scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]
     // would be more elegant with regex. Not yet supported on my dev machine's gcc 4.8 :(
-    LOG(DEBUG) << "StreamUri: " << streamUri << "\n";
+    LOG(DEBUG, LOG_TAG) << "StreamUri: " << stream_uri << "\n";
     size_t pos;
-    uri = strutils::trim_copy(streamUri);
+
+    // Remove leading and trailing quotes
+    uri = strutils::trim_copy(stream_uri);
     while (!uri.empty() && ((uri[0] == '\'') || (uri[0] == '"')))
         uri = uri.substr(1);
     while (!uri.empty() && ((uri[uri.length() - 1] == '\'') || (uri[uri.length() - 1] == '"')))
         uri = uri.substr(0, this->uri.length() - 1);
 
     // string decodedUri = strutils::uriDecode(uri);
-    // LOG(DEBUG) << "StreamUri decoded: " << decodedUri << "\n";
+    // LOG(DEBUG, LOG_TAG) << "StreamUri decoded: " << decodedUri << "\n";
 
     string tmp(uri);
 
+    // Parse scheme
     pos = tmp.find(':');
     if (pos == string::npos)
         throw invalid_argument("missing ':'");
     scheme = strutils::uriDecode(strutils::trim_copy(tmp.substr(0, pos)));
     tmp = tmp.substr(pos + 1);
-    LOG(TRACE) << "scheme: '" << scheme << "', tmp: '" << tmp << "'\n";
+    LOG(TRACE, LOG_TAG) << "scheme: '" << scheme << "', tmp: '" << tmp << "'\n";
+    // tmp = //[user:password@]host[:port][/]path[?query][#fragment]
 
     if (tmp.find("//") != 0)
         throw invalid_argument("missing host separator: '//'");
     tmp = tmp.substr(2);
+    // tmp = [user:password@]host[:port][/]path[?query][#fragment]
 
     pos = tmp.find('/');
     if (pos == string::npos)
@@ -76,13 +83,15 @@ void StreamUri::parse(const std::string& streamUri)
         if (pos == string::npos)
             pos = tmp.length();
     }
+    // [user:password@]host[:port][/]path[?query][#fragment]
+    // pos:                        ^  or  ^  or             ^
 
     host = strutils::uriDecode(strutils::trim_copy(tmp.substr(0, pos)));
     tmp = tmp.substr(pos);
     path = tmp;
     pos = std::min(path.find('?'), path.find('#'));
     path = strutils::uriDecode(strutils::trim_copy(path.substr(0, pos)));
-    LOG(TRACE) << "host: '" << host << "', tmp: '" << tmp << "', path: '" << path << "'\n";
+    LOG(TRACE, LOG_TAG) << "host: '" << host << "', tmp: '" << tmp << "', path: '" << path << "'\n";
 
     string queryStr;
     pos = tmp.find('?');
@@ -90,7 +99,7 @@ void StreamUri::parse(const std::string& streamUri)
     {
         tmp = tmp.substr(pos + 1);
         queryStr = tmp;
-        LOG(TRACE) << "path: '" << path << "', tmp: '" << tmp << "', query: '" << queryStr << "'\n";
+        LOG(TRACE, LOG_TAG) << "path: '" << path << "', tmp: '" << tmp << "', query: '" << queryStr << "'\n";
     }
 
     pos = tmp.find('#');
@@ -99,7 +108,7 @@ void StreamUri::parse(const std::string& streamUri)
         queryStr = tmp.substr(0, pos);
         tmp = tmp.substr(pos + 1);
         fragment = strutils::uriDecode(strutils::trim_copy(tmp));
-        LOG(TRACE) << "query: '" << queryStr << "', fragment: '" << fragment << "', tmp: '" << tmp << "'\n";
+        LOG(TRACE, LOG_TAG) << "query: '" << queryStr << "', fragment: '" << fragment << "', tmp: '" << tmp << "'\n";
     }
 
     vector<string> keyValueList = strutils::split(queryStr, '&');
@@ -113,15 +122,16 @@ void StreamUri::parse(const std::string& streamUri)
             query[key] = value;
         }
     }
-    LOG(DEBUG) << "StreamUri.toString: " << toString() << "\n";
+    LOG(DEBUG, LOG_TAG) << "StreamUri.toString: " << toString() << "\n";
 }
 
 
 std::string StreamUri::toString() const
 {
+    // TODO: path must be properly be uri encoded
     // scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]
     stringstream ss;
-    ss << scheme << "://" << host << "/" + path;
+    ss << scheme << "://" << host << path;
     if (!query.empty())
     {
         ss << "?";
@@ -155,4 +165,10 @@ std::string StreamUri::getQuery(const std::string& key, const std::string& def)
         return iter->second;
     return def;
 }
+
+bool StreamUri::operator==(const StreamUri& other) const
+{
+    return (other.scheme == scheme) && (other.host == host) && (other.path == path) && (other.query == query) && (other.fragment == fragment);
+}
+
 } // namespace streamreader

server/streamreader/stream_uri.hpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2025  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -32,32 +32,49 @@ using json = nlohmann::json;
 namespace streamreader
 {
 
-// scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]
+/// URI with the general format:
+///  scheme:[//[user:password@]host[:port]][/]path[?query][#fragment]
 struct StreamUri
 {
-    StreamUri(const std::string& uri);
+    /// c'tor construct from string @p uri
+    explicit StreamUri(const std::string& uri);
+
+    /// the complete uri
     std::string uri;
+    /// the scheme component (pipe, http, file, tcp, ...)
     std::string scheme;
-    /*	struct Authority
-            {
-                    std::string username;
-                    std::string password;
-                    std::string host;
-                    size_t port;
-            };
-            Authority authority;
-    */
+    // struct Authority
+    // {
+    //     std::string username;
+    //     std::string password;
+    //     std::string host;
+    //     size_t port;
+    // };
+    // Authority authority;
+
+    /// the host component
     std::string host;
+    /// the path component
     std::string path;
+    /// the query component: "key = value" pairs
     std::map<std::string, std::string> query;
+    /// the fragment component
     std::string fragment;
 
-    std::string id() const;
+    /// @return URI as json
     json toJson() const;
+
+    /// @return value for a @p key or @p def, if key does not exist
     std::string getQuery(const std::string& key, const std::string& def = "") const;
 
-    void parse(const std::string& streamUri);
+    /// parse @p stream_uri string
+    void parse(const std::string& stream_uri);
+
+    /// @return uri as string
     std::string toString() const;
+
+    /// @return true if @p other is equal to this
+    bool operator==(const StreamUri& other) const;
 };
 
 } // namespace streamreader

test/test_main.cpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2024  Johannes Pohl
+    Copyright (C) 2014-2025  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -290,6 +290,9 @@ TEST_CASE("Uri")
     REQUIRE(uri.query["devicename"] == "Snapcast");
     REQUIRE(uri.query["bitrate"] == "320");
     REQUIRE(uri.query["killall"] == "false");
+    REQUIRE(uri.toString().find("spotify:///librespot?") == 0);
+    StreamUri uri_from_str{uri.toString()};
+    // REQUIRE(uri == uri_from_str);
 }