libssh2: Fix infinite loop when enabling callback without handlers

When libssh2_session_callback_set() is used to activate a callback for which no handler was registered in libssh2_session_init_ex(), this can result in an infinite loop because the user event from lvssh2 is always registered automatically. When the callback is activated, it always returns default values because the VI refnum is undefined. This changes the implementation so that the LabVIEW user event is only created when a valid VI refnum is provided. The extension library returns an error if the user event does not exist, which effectively breaks any infinite loops.
logmanoriginal · Oct 4, 2024 · 898305a · 898305a
1 parent 89c0972
commit 898305a
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Showing 22 changed files with 44 additions and 6 deletions.
diff --git a/extensions/lvssh2_extensions.c b/extensions/lvssh2_extensions.c
@@ -20,6 +20,12 @@ void lvssh2_trace_handler_function(LIBSSH2_SESSION* session, void* context, cons
 LIBSSH2_SEND_FUNC(lvssh2_session_callback_send_function) {
 	ASSERT_LABVIEW_MAXLEN(length);
 
+	lvssh2_abstract* lv_abstract = *(lvssh2_abstract**)abstract;
+	if (!lv_abstract->send)
+	{
+		return LIBSSH2_ERROR_BAD_USE;
+	}
+
 	lvssh2_session_callback_send_function_input_args payload = { 0 };
 	payload.socket = socket;
 	payload.buffer = NULL;
@@ -30,7 +36,6 @@ LIBSSH2_SEND_FUNC(lvssh2_session_callback_send_function) {
 
 	data_buffer_to_LStrHandle(buffer, (int32)length, &payload.buffer);
 
-	lvssh2_abstract* lv_abstract = *(lvssh2_abstract**)abstract;
 	PostLVUserEvent(lv_abstract->send, &payload);
 
 	DSDisposeHandle(payload.buffer);
@@ -39,6 +44,12 @@ LIBSSH2_SEND_FUNC(lvssh2_session_callback_send_function) {
 }
 
 LIBSSH2_RECV_FUNC(lvssh2_session_callback_recv_function) {
+	lvssh2_abstract* lv_abstract = *(lvssh2_abstract**)abstract;
+	if (!lv_abstract->recv)
+	{
+		return LIBSSH2_ERROR_BAD_USE;
+	}
+
 	lvssh2_session_callback_recv_function_input_args payload = { 0 };
 	payload.socket = socket;
 	payload.buffer = buffer;
@@ -48,8 +59,6 @@ LIBSSH2_RECV_FUNC(lvssh2_session_callback_recv_function) {
 	ssize_t bytes_received = 0;
 	payload.bytes_received = &bytes_received;
 
-	lvssh2_abstract* lv_abstract = *(lvssh2_abstract**)abstract;
-
 	PostLVUserEvent(lv_abstract->recv, &payload);
 
 	return bytes_received;
@@ -63,6 +72,12 @@ LIBSSH2_USERAUTH_KBDINT_RESPONSE_FUNC(lvssh2_userauth_keyboard_interactive_respo
 		return;
 	}
 
+	lvssh2_abstract* lv_abstract = *(lvssh2_abstract**)abstract;
+	if (!lv_abstract->kbdint_response)
+	{
+		return;
+	}
+
 	LStrHandle* lv_responses = (LStrHandle*)malloc(num_prompts * sizeof(LStrHandle));
 	if (!lv_responses) {
 		return;
@@ -81,8 +96,6 @@ LIBSSH2_USERAUTH_KBDINT_RESPONSE_FUNC(lvssh2_userauth_keyboard_interactive_respo
 	payload.prompts = prompts;
 	payload.responses = lv_responses;
 
-	lvssh2_abstract* lv_abstract = *(lvssh2_abstract**)abstract;
-
 	PostLVUserEvent(lv_abstract->kbdint_response, &payload);
 
 	for (int i = 0; i < num_prompts; i++) {

diff --git a/libssh2/Create Session Refnum.vi b/libssh2/Create Session Refnum.vi
diff --git a/libssh2/Delete Session Refnum.vi b/libssh2/Delete Session Refnum.vi
diff --git a/libssh2/Read Session Refnum.vi b/libssh2/Read Session Refnum.vi
diff --git a/libssh2/Session Refnum Data.ctl b/libssh2/Session Refnum Data.ctl
diff --git a/libssh2/libssh2.lvlib b/libssh2/libssh2.lvlib
@@ -124,6 +124,9 @@
 		<Item Name="Read Session Refnum.vi" Type="VI" URL="../Read Session Refnum.vi">
 			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
 		</Item>
+		<Item Name="Session Refnum Data.ctl" Type="VI" URL="../Session Refnum Data.ctl">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
 		<Item Name="Session Refnum.ctl" Type="VI" URL="../Session Refnum.ctl"/>
 	</Item>
 	<Item Name="Session Callback" Type="Folder">
@@ -133,7 +136,9 @@
 		<Item Name="lvssh2_session_callback_events_init.vi" Type="VI" URL="../lvssh2_session_callback_events_init.vi">
 			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
 		</Item>
-		<Item Name="lvssh2_session_callback_get_function.vi" Type="VI" URL="../lvssh2_session_callback_get_function.vi"/>
+		<Item Name="lvssh2_session_callback_get_function.vi" Type="VI" URL="../lvssh2_session_callback_get_function.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
 		<Item Name="lvssh2_session_callback_receive.vit" Type="VI" URL="../lvssh2_session_callback_receive.vit"/>
 		<Item Name="lvssh2_session_callback_receive_function_input_args_32.ctl" Type="VI" URL="../lvssh2_session_callback_receive_function_input_args_32.ctl">
 			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
@@ -147,6 +152,24 @@
 		<Item Name="lvssh2_session_callback_receive_handler_64.vi" Type="VI" URL="../lvssh2_session_callback_receive_handler_64.vi">
 			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
 		</Item>
+		<Item Name="lvssh2_session_callback_register_kbdint_response_32.vi" Type="VI" URL="../lvssh2_session_callback_register_kbdint_response_32.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
+		<Item Name="lvssh2_session_callback_register_kbdint_response_64.vi" Type="VI" URL="../lvssh2_session_callback_register_kbdint_response_64.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
+		<Item Name="lvssh2_session_callback_register_receive_32.vi" Type="VI" URL="../lvssh2_session_callback_register_receive_32.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
+		<Item Name="lvssh2_session_callback_register_receive_64.vi" Type="VI" URL="../lvssh2_session_callback_register_receive_64.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
+		<Item Name="lvssh2_session_callback_register_send_32.vi" Type="VI" URL="../lvssh2_session_callback_register_send_32.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
+		<Item Name="lvssh2_session_callback_register_send_64.vi" Type="VI" URL="../lvssh2_session_callback_register_send_64.vi">
+			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>
+		</Item>
 		<Item Name="lvssh2_session_callback_send.vit" Type="VI" URL="../lvssh2_session_callback_send.vit"/>
 		<Item Name="lvssh2_session_callback_send_function_input_args_32.ctl" Type="VI" URL="../lvssh2_session_callback_send_function_input_args_32.ctl">
 			<Property Name="NI.LibItem.Scope" Type="Int">2</Property>

diff --git a/libssh2/libssh2_session_abstract.vi b/libssh2/libssh2_session_abstract.vi
diff --git a/libssh2/libssh2_session_init_ex.vi b/libssh2/libssh2_session_init_ex.vi
diff --git a/libssh2/lvssh2_extensions.dll b/libssh2/lvssh2_extensions.dll
diff --git a/libssh2/lvssh2_extensions_64.dll b/libssh2/lvssh2_extensions_64.dll
diff --git a/libssh2/lvssh2_session_callback_events_init.vi b/libssh2/lvssh2_session_callback_events_init.vi
diff --git a/libssh2/lvssh2_session_callback_receive_handler_64.vi b/libssh2/lvssh2_session_callback_receive_handler_64.vi
diff --git a/libssh2/lvssh2_session_callback_register_kbdint_response_32.vi b/libssh2/lvssh2_session_callback_register_kbdint_response_32.vi
diff --git a/libssh2/lvssh2_session_callback_register_kbdint_response_64.vi b/libssh2/lvssh2_session_callback_register_kbdint_response_64.vi
diff --git a/libssh2/lvssh2_session_callback_register_receive_32.vi b/libssh2/lvssh2_session_callback_register_receive_32.vi
diff --git a/libssh2/lvssh2_session_callback_register_receive_64.vi b/libssh2/lvssh2_session_callback_register_receive_64.vi
diff --git a/libssh2/lvssh2_session_callback_register_send_32.vi b/libssh2/lvssh2_session_callback_register_send_32.vi
diff --git a/libssh2/lvssh2_session_callback_register_send_64.vi b/libssh2/lvssh2_session_callback_register_send_64.vi
diff --git a/libssh2/lvssh2_session_callback_send_handler_64.vi b/libssh2/lvssh2_session_callback_send_handler_64.vi
diff --git a/tests/integration_tests/integration_tests.lvlib b/tests/integration_tests/integration_tests.lvlib
@@ -38,6 +38,7 @@
 	<Item Name="test_libssh2_session_banner_get.vi" Type="VI" URL="../test_libssh2_session_banner_get.vi"/>
 	<Item Name="test_libssh2_session_banner_set.vi" Type="VI" URL="../test_libssh2_session_banner_set.vi"/>
 	<Item Name="test_libssh2_session_block_directions.vi" Type="VI" URL="../test_libssh2_session_block_directions.vi"/>
+	<Item Name="test_libssh2_session_callback_set - no handler.vi" Type="VI" URL="../test_libssh2_session_callback_set - no handler.vi"/>
 	<Item Name="test_libssh2_session_callback_set.vi" Type="VI" URL="../test_libssh2_session_callback_set.vi"/>
 	<Item Name="test_libssh2_session_disconnect.vi" Type="VI" URL="../test_libssh2_session_disconnect.vi"/>
 	<Item Name="test_libssh2_session_handshake.vi" Type="VI" URL="../test_libssh2_session_handshake.vi"/>
@@ -72,6 +73,7 @@
 	<Item Name="test_libssh2_sftp_write.vi" Type="VI" URL="../test_libssh2_sftp_write.vi"/>
 	<Item Name="test_libssh2_userauth_authenticated.vi" Type="VI" URL="../test_libssh2_userauth_authenticated.vi"/>
 	<Item Name="test_libssh2_userauth_banner.vi" Type="VI" URL="../test_libssh2_userauth_banner.vi"/>
+	<Item Name="test_libssh2_userauth_keyboard_interactive_ex - no handler.vi" Type="VI" URL="../test_libssh2_userauth_keyboard_interactive_ex - no handler.vi"/>
 	<Item Name="test_libssh2_userauth_keyboard_interactive_ex.vi" Type="VI" URL="../test_libssh2_userauth_keyboard_interactive_ex.vi"/>
 	<Item Name="test_libssh2_userauth_list.vi" Type="VI" URL="../test_libssh2_userauth_list.vi"/>
 	<Item Name="test_libssh2_userauth_password.vi" Type="VI" URL="../test_libssh2_userauth_password.vi"/>

diff --git a/tests/integration_tests/test_libssh2_session_callback_set - no handler.vi b/tests/integration_tests/test_libssh2_session_callback_set - no handler.vi
diff --git a/tests/integration_tests/test_libssh2_userauth_keyboard_interactive_ex - no handler.vi b/tests/integration_tests/test_libssh2_userauth_keyboard_interactive_ex - no handler.vi