Add RPC Whitelist Feature from #12248

Author: JeremyRubin

src/httprpc.cpp

@@ -15,8 +15,13 @@
 #include <util/translation.h>
 #include <walletinitinterface.h>
 
+#include <algorithm>
+#include <iterator>
+#include <map>
 #include <memory>
 #include <stdio.h>
+#include <set>
+#include <string>
 
 #include <boost/algorithm/string.hpp> // boost::trim
 
@@ -64,6 +69,9 @@ class HTTPRPCTimerInterface : public RPCTimerInterface
 static std::string strRPCUserColonPass;
 /* Stored RPC timer interface (for unregistration) */
 static std::unique_ptr<HTTPRPCTimerInterface> httpRPCTimerInterface;
+/* RPC Auth Whitelist */
+static std::map<std::string, std::set<std::string>> g_rpc_whitelist;
+static bool g_rpc_whitelist_default = false;
 
 static void JSONErrorReply(HTTPRequest* req, const UniValue& objError, const UniValue& id)
 {
@@ -183,18 +191,45 @@ static bool HTTPReq_JSONRPC(HTTPRequest* req, const std::string &)
         jreq.URI = req->GetURI();
 
         std::string strReply;
+        bool user_has_whitelist = g_rpc_whitelist.count(jreq.authUser);
+        if (!user_has_whitelist && g_rpc_whitelist_default) {
+            LogPrintf("RPC User %s not allowed to call any methods\n", jreq.authUser);
+            req->WriteReply(HTTP_FORBIDDEN);
+            return false;
+
         // singleton request
-        if (valRequest.isObject()) {
+        } else if (valRequest.isObject()) {
             jreq.parse(valRequest);
-
+            if (user_has_whitelist && !g_rpc_whitelist[jreq.authUser].count(jreq.strMethod)) {
+                LogPrintf("RPC User %s not allowed to call method %s\n", jreq.authUser, jreq.strMethod);
+                req->WriteReply(HTTP_FORBIDDEN);
+                return false;
+            }
             UniValue result = tableRPC.execute(jreq);
 
             // Send reply
             strReply = JSONRPCReply(result, NullUniValue, jreq.id);
 
         // array of requests
-        } else if (valRequest.isArray())
+        } else if (valRequest.isArray()) {
+            if (user_has_whitelist) {
+                for (unsigned int reqIdx = 0; reqIdx < valRequest.size(); reqIdx++) {
+                    if (!valRequest[reqIdx].isObject()) {
+                        throw JSONRPCError(RPC_INVALID_REQUEST, "Invalid Request object");
+                    } else {
+                        const UniValue& request = valRequest[reqIdx].get_obj();
+                        // Parse method
+                        std::string strMethod = find_value(request, "method").get_str();
+                        if (!g_rpc_whitelist[jreq.authUser].count(strMethod)) {
+                            LogPrintf("RPC User %s not allowed to call method %s\n", jreq.authUser, strMethod);
+                            req->WriteReply(HTTP_FORBIDDEN);
+                            return false;
+                        }
+                    }
+                }
+            }
             strReply = JSONRPCExecBatch(jreq, valRequest.get_array());
+        }
         else
             throw JSONRPCError(RPC_PARSE_ERROR, "Top-level object parse error");
 
@@ -229,6 +264,27 @@ static bool InitRPCAuthentication()
     {
         LogPrintf("Using rpcauth authentication.\n");
     }
+
+    g_rpc_whitelist_default = gArgs.GetBoolArg("-rpcwhitelistdefault", gArgs.IsArgSet("-rpcwhitelist"));
+    for (const std::string& strRPCWhitelist : gArgs.GetArgs("-rpcwhitelist")) {
+        auto pos = strRPCWhitelist.find(':');
+        std::string strUser = strRPCWhitelist.substr(0, pos);
+        bool intersect = g_rpc_whitelist.count(strUser);
+        std::set<std::string>& whitelist = g_rpc_whitelist[strUser];
+        if (pos != std::string::npos) {
+            std::string strWhitelist = strRPCWhitelist.substr(pos + 1);
+            std::set<std::string> new_whitelist;
+            boost::split(new_whitelist, strWhitelist, boost::is_any_of(", "));
+            if (intersect) {
+                std::set<std::string> tmp_whitelist;
+                std::set_intersection(new_whitelist.begin(), new_whitelist.end(),
+                       whitelist.begin(), whitelist.end(), std::inserter(tmp_whitelist, tmp_whitelist.end()));
+                new_whitelist = std::move(tmp_whitelist);
+            }
+            whitelist = std::move(new_whitelist);
+        }
+    }
+
     return true;
 }
 

src/init.cpp

@@ -534,6 +534,8 @@ void SetupServerArgs()
     gArgs.AddArg("-rpcservertimeout=<n>", strprintf("Timeout during HTTP requests (default: %d)", DEFAULT_HTTP_SERVER_TIMEOUT), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::RPC);
     gArgs.AddArg("-rpcthreads=<n>", strprintf("Set the number of threads to service RPC calls (default: %d)", DEFAULT_HTTP_THREADS), ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
     gArgs.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections", ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
+    gArgs.AddArg("-rpcwhitelist=<whitelist>", "Set a whitelist to filter incoming RPC calls for a specific user. The field <whitelist> comes in the format: <USERNAME>:<rpc 1>,<rpc 2>,...,<rpc n>. If multiple whitelists are set for a given user, they are set-intersected. See -rpcwhitelistdefault documentation for information on default whitelist behavior.", ArgsManager::ALLOW_ANY, OptionsCategory::RPC);
+    gArgs.AddArg("-rpcwhitelistdefault", "Sets default behavior for rpc whitelisting. Unless rpcwhitelistdefault is set to 0, if any -rpcwhitelist is set, the rpc server acts as if all rpc users are subject to empty-unless-otherwise-specified whitelists. If rpcwhitelistdefault is set to 1 and no -rpcwhitelist is set, rpc server acts as if all rpc users are subject to empty whitelists.", ArgsManager::ALLOW_BOOL, OptionsCategory::RPC);
     gArgs.AddArg("-rpcworkqueue=<n>", strprintf("Set the depth of the work queue to service RPC calls (default: %d)", DEFAULT_HTTP_WORKQUEUE), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::RPC);
     gArgs.AddArg("-server", "Accept command line and JSON-RPC commands", ArgsManager::ALLOW_ANY, OptionsCategory::RPC);