sm: fix deadlock semantics surrounding mitm installation

libraries/libstratosphere/include/stratosphere/sm/impl/sm_user_interface.hpp

@@ -32,6 +32,7 @@ namespace ams::sm::impl {
         AMS_SF_METHOD_INFO(C, H, 65004, Result, AtmosphereHasMitm,                (sf::Out<bool> out, ServiceName service))                                             \
         AMS_SF_METHOD_INFO(C, H, 65005, Result, AtmosphereWaitMitm,               (ServiceName service))                                                                \
         AMS_SF_METHOD_INFO(C, H, 65006, Result, AtmosphereDeclareFutureMitm,      (ServiceName service))                                                                \
+        AMS_SF_METHOD_INFO(C, H, 65007, Result, AtmosphereClearFutureMitm,        (ServiceName service))                                                                \
         AMS_SF_METHOD_INFO(C, H, 65100, Result, AtmosphereHasService,             (sf::Out<bool> out, ServiceName service))                                             \
         AMS_SF_METHOD_INFO(C, H, 65101, Result, AtmosphereWaitService,            (ServiceName service))
 

libraries/libstratosphere/include/stratosphere/sm/sm_mitm_api.hpp

@@ -24,6 +24,7 @@ namespace ams::sm::mitm {
     Result InstallMitm(Handle *out_port, Handle *out_query, ServiceName name);
     Result UninstallMitm(ServiceName name);
     Result DeclareFutureMitm(ServiceName name);
+    Result ClearFutureMitm(ServiceName name);
     Result AcknowledgeSession(Service *out_service, MitmProcessInfo *out_info, ServiceName name);
     Result HasMitm(bool *out, ServiceName name);
     Result WaitMitm(ServiceName name);

libraries/libstratosphere/source/sf/hipc/sf_hipc_server_manager.cpp

@@ -27,6 +27,10 @@ namespace ams::sf::hipc {
 
         /* Register the query handle. */
         impl::RegisterMitmQueryHandle(query_handle, query_func);
+
+        /* Clear future declarations if any, now that our query handler is present. */
+        R_ABORT_UNLESS(sm::mitm::ClearFutureMitm(service_name));
+
         return ResultSuccess();
     }
 

libraries/libstratosphere/source/sm/sm_ams.c

@@ -107,6 +107,10 @@ Result smAtmosphereMitmDeclareFuture(SmServiceName name) {
     return _smAtmosphereCmdInServiceNameNoOut(name, smGetServiceSession(), 65006);
 }
 
+Result smAtmosphereMitmClearFuture(SmServiceName name) {
+    return _smAtmosphereCmdInServiceNameNoOut(name, smGetServiceSession(), 65007);
+}
+
 Result smAtmosphereMitmAcknowledgeSession(Service *srv_out, void *_out, SmServiceName name) {
     struct {
         u64 process_id;

libraries/libstratosphere/source/sm/sm_ams.h

@@ -26,6 +26,7 @@ void smAtmosphereCloseSession(Service *srv);
 Result smAtmosphereMitmInstall(Service *fwd_srv, Handle *handle_out, Handle *query_out, SmServiceName name);
 Result smAtmosphereMitmUninstall(SmServiceName name);
 Result smAtmosphereMitmDeclareFuture(SmServiceName name);
+Result smAtmosphereMitmClearFuture(SmServiceName name);
 Result smAtmosphereMitmAcknowledgeSession(Service *srv_out, void *info_out, SmServiceName name);
 
 #ifdef __cplusplus

libraries/libstratosphere/source/sm/sm_mitm_api.cpp

@@ -37,6 +37,12 @@ namespace ams::sm::mitm {
         });
     }
 
+    Result ClearFutureMitm(ServiceName name) {
+        return impl::DoWithUserSession([&]() {
+            return smAtmosphereMitmClearFuture(impl::ConvertName(name));
+        });
+    }
+
     Result AcknowledgeSession(Service *out_service, MitmProcessInfo *out_info, ServiceName name) {
         return impl::DoWithMitmAcknowledgementSession([&]() {
             return smAtmosphereMitmAcknowledgeSession(out_service, reinterpret_cast<void *>(out_info), impl::ConvertName(name));

stratosphere/sm/source/impl/sm_service_manager.cpp

@@ -588,6 +588,15 @@ namespace ams::sm::impl {
         *out = INVALID_HANDLE;
         *out_query = INVALID_HANDLE;
 
+        /* If we don't have a future mitm declaration, add one. */
+        /* Client will clear this when ready to process. */
+        bool has_existing_future_declaration = HasFutureMitmDeclaration(service);
+        if (!has_existing_future_declaration) {
+            R_TRY(AddFutureMitmDeclaration(service));
+        }
+
+        auto future_guard = SCOPE_GUARD { if (!has_existing_future_declaration) { ClearFutureMitmDeclaration(service); } };
+
         /* Create mitm handles. */
         {
             os::ManagedHandle hnd, port_hnd, qry_hnd, mitm_qry_hnd;
@@ -603,9 +612,7 @@ namespace ams::sm::impl {
             *out_query = qry_hnd.Move();
         }
 
-        /* Clear the future declaration, if one exists. */
+        future_guard.Cancel();
-        ClearFutureMitmDeclaration(service);
-
         return ResultSuccess();
     }
 
@@ -651,6 +658,34 @@ namespace ams::sm::impl {
         return ResultSuccess();
     }
 
+    Result ClearFutureMitm(os::ProcessId process_id, ServiceName service) {
+        /* Validate service name. */
+        R_TRY(ValidateServiceName(service));
+
+        /* Check that the process is registered and allowed to register the service. */
+        if (!IsInitialProcess(process_id)) {
+            ProcessInfo *proc = GetProcessInfo(process_id);
+            R_UNLESS(proc != nullptr, sm::ResultInvalidClient());
+            R_TRY(ValidateAccessControl(AccessControlEntry(proc->access_control, proc->access_control_size), service, true, false));
+        }
+
+        /* Check that a future mitm declaration is present or we have a mitm. */
+        if (HasMitm(service)) {
+            /* Validate that the service exists. */
+            ServiceInfo *service_info = GetServiceInfo(service);
+            R_UNLESS(service_info != nullptr, sm::ResultNotRegistered());
+
+            /* Validate that the client process_id is the mitm process. */
+            R_UNLESS(service_info->mitm_process_id == process_id, sm::ResultNotAllowed());
+        } else {
+            R_UNLESS(HasFutureMitmDeclaration(service), sm::ResultNotRegistered());
+        }
+
+        /* Clear the forward declaration. */
+        ClearFutureMitmDeclaration(service);
+        return ResultSuccess();
+    }
+
     Result AcknowledgeMitmSession(MitmProcessInfo *out_info, Handle *out_hnd, os::ProcessId process_id, ServiceName service) {
         /* Validate service name. */
         R_TRY(ValidateServiceName(service));

stratosphere/sm/source/impl/sm_service_manager.hpp

@@ -37,6 +37,7 @@ namespace ams::sm::impl {
     Result InstallMitm(Handle *out, Handle *out_query, os::ProcessId process_id, ServiceName service);
     Result UninstallMitm(os::ProcessId process_id, ServiceName service);
     Result DeclareFutureMitm(os::ProcessId process_id, ServiceName service);
+    Result ClearFutureMitm(os::ProcessId process_id, ServiceName service);
     Result AcknowledgeMitmSession(MitmProcessInfo *out_info, Handle *out_hnd, os::ProcessId process_id, ServiceName service);
 
     /* Dmnt record extensions. */

stratosphere/sm/source/sm_user_service.cpp

@@ -75,6 +75,11 @@ namespace ams::sm {
         return impl::DeclareFutureMitm(this->process_id, service);
     }
 
+    Result UserService::AtmosphereClearFutureMitm(ServiceName service) {
+        R_TRY(this->EnsureInitialized());
+        return impl::ClearFutureMitm(this->process_id, service);
+    }
+
 
     Result UserService::AtmosphereHasService(sf::Out<bool> out, ServiceName service) {
         R_TRY(this->EnsureInitialized());

stratosphere/sm/source/sm_user_service.hpp

@@ -40,6 +40,7 @@ namespace ams::sm {
             Result AtmosphereHasMitm(sf::Out<bool> out, ServiceName service);
             Result AtmosphereWaitMitm(ServiceName service);
             Result AtmosphereDeclareFutureMitm(ServiceName service);
+            Result AtmosphereClearFutureMitm(ServiceName service);
 
             Result AtmosphereHasService(sf::Out<bool> out, ServiceName service);
             Result AtmosphereWaitService(ServiceName service);