GUACAMOLE-1059: Add explanatory comments and additional logging.

src/protocols/rdp/channels/rdpdr/rdpdr-fs-messages-file-info.c

@@ -136,9 +136,13 @@ void guac_rdpdr_fs_process_set_rename_info(guac_rdp_common_svc* svc,
     char destination_path[GUAC_RDP_FS_MAX_PATH];
 
     /* Check stream size prior to reading. */
-    if (Stream_GetRemainingLength(input_stream) < 6)
+    if (Stream_GetRemainingLength(input_stream) < 6) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File Stream does not "
+                "contain the required number of bytes.  File sharing may not "
+                "work as expected.");
         return;
-    
+    }
+        
     /* Read structure */
     Stream_Seek_UINT8(input_stream); /* ReplaceIfExists */
     Stream_Seek_UINT8(input_stream); /* RootDirectory */

src/protocols/rdp/channels/rdpdr/rdpdr-fs-messages.c

@@ -49,8 +49,12 @@ void guac_rdpdr_fs_process_create(guac_rdp_common_svc* svc,
     char path[GUAC_RDP_FS_MAX_PATH];
 
     /* Check remaining stream data prior to reading. */
-    if (Stream_GetRemainingLength(input_stream) < 32)
+    if (Stream_GetRemainingLength(input_stream) < 32) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     /* Read "create" information */
     Stream_Read_UINT32(input_stream, desired_access);
@@ -128,8 +132,12 @@ void guac_rdpdr_fs_process_read(guac_rdp_common_svc* svc,
     wStream* output_stream;
 
     /* Check remaining bytes before reading stream. */
-    if (Stream_GetRemainingLength(input_stream) < 12)
+    if (Stream_GetRemainingLength(input_stream) < 12) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File Stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     /* Read packet */
     Stream_Read_UINT32(input_stream, length);
@@ -181,8 +189,12 @@ void guac_rdpdr_fs_process_write(guac_rdp_common_svc* svc,
     wStream* output_stream;
 
     /* Check remaining length. */
-    if (Stream_GetRemainingLength(input_stream) < 32)
+    if (Stream_GetRemainingLength(input_stream) < 32) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File Stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     /* Read packet */
     Stream_Read_UINT32(input_stream, length);
@@ -257,8 +269,12 @@ void guac_rdpdr_fs_process_volume_info(guac_rdp_common_svc* svc,
     int fs_information_class;
 
     /* Check remaining length */
-    if (Stream_GetRemainingLength(input_stream) < 4)
+    if (Stream_GetRemainingLength(input_stream) < 4) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File Stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     Stream_Read_UINT32(input_stream, fs_information_class);
 
@@ -299,8 +315,12 @@ void guac_rdpdr_fs_process_file_info(guac_rdp_common_svc* svc,
     int fs_information_class;
 
     /* Check remaining length */
-    if (Stream_GetRemainingLength(input_stream) < 4)
+    if (Stream_GetRemainingLength(input_stream) < 4) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File Stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     Stream_Read_UINT32(input_stream, fs_information_class);
 
@@ -349,8 +369,12 @@ void guac_rdpdr_fs_process_set_file_info(guac_rdp_common_svc* svc,
     int length;
 
     /* Check remaining length */
-    if (Stream_GetRemainingLength(input_stream) < 32)
+    if (Stream_GetRemainingLength(input_stream) < 32) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     Stream_Read_UINT32(input_stream, fs_information_class);
     Stream_Read_UINT32(input_stream, length); /* Length */
@@ -430,8 +454,12 @@ void guac_rdpdr_fs_process_query_directory(guac_rdp_common_svc* svc,
     if (file == NULL)
         return;
 
-    if (Stream_GetRemainingLength(input_stream) < 9)
+    if (Stream_GetRemainingLength(input_stream) < 9) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "File stream does not "
+                "contain the expected number of bytes. File sharing may not "
+                "work as expected.");
         return;
+    }
     
     /* Read main header */
     Stream_Read_UINT32(input_stream, fs_information_class);
@@ -441,8 +469,16 @@ void guac_rdpdr_fs_process_query_directory(guac_rdp_common_svc* svc,
     /* If this is the first query, the path is included after padding */
     if (initial_query) {
 
-        if (Stream_GetRemainingLength(input_stream) < 23)
+        /*
+         * Check to make sure Stream has at least the 23 padding bytes in it
+         * prior to seeking.
+         */
+        if (Stream_GetRemainingLength(input_stream) < 23) {
+            guac_client_log(svc->client, GUAC_LOG_WARNING, "File stream does "
+                    "not contain the expected number of bytes. File sharing "
+                    "may not work as expected.");
             return;
+        }
         
         Stream_Seek(input_stream, 23);       /* Padding */
 

src/protocols/rdp/channels/rdpdr/rdpdr-messages.c

@@ -212,6 +212,7 @@ void guac_rdpdr_process_server_announce(guac_rdp_common_svc* svc,
 
     unsigned int major, minor, client_id;
 
+    /* Stream should contain at least 8 bytes (UINT16 + UINT16 + UINT32) */
     if (Stream_GetRemainingLength(input_stream) < 8)
         return;
     
@@ -246,8 +247,13 @@ void guac_rdpdr_process_device_reply(guac_rdp_common_svc* svc,
     unsigned int device_id, ntstatus;
     int severity, c, n, facility, code;
 
-    if (Stream_GetRemainingLength(input_stream) < 8)
+    /* Stream should contain at least 8 bytes (UINT32 + UINT32 ) */
+    if (Stream_GetRemainingLength(input_stream) < 8) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Device Stream does not "
+                "contain the expected number of bytes. Device redirection may "
+                "not work.");
         return;
+    }
     
     Stream_Read_UINT32(input_stream, device_id);
     Stream_Read_UINT32(input_stream, ntstatus);
@@ -284,8 +290,13 @@ void guac_rdpdr_process_device_iorequest(guac_rdp_common_svc* svc,
     guac_rdpdr* rdpdr = (guac_rdpdr*) svc->data;
     guac_rdpdr_iorequest iorequest;
 
-    if (Stream_GetRemainingLength(input_stream) < 20)
+    /* Check to make sure the Stream contains at least 20 bytes (5 x UINT32 ). */
+    if (Stream_GetRemainingLength(input_stream) < 20) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Device Stream does not "
+                "contain the expected number of bytes. Device redirection may "
+                "not work as expected.");
         return;
+    }
     
     /* Read header */
     Stream_Read_UINT32(input_stream, iorequest.device_id);
@@ -315,8 +326,13 @@ void guac_rdpdr_process_server_capability(guac_rdp_common_svc* svc,
     int count;
     int i;
 
-    if (Stream_GetRemainingLength(input_stream) < 4)
+    /* Check to make sure the Stream has at least 4 bytes (UINT16 + 2) */
+    if (Stream_GetRemainingLength(input_stream) < 4) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Redirection Stream "
+                "does not contain the expected number of bytes. Device "
+                "redirection may not work as expected.");
         return;
+    }
     
     /* Read header */
     Stream_Read_UINT16(input_stream, count);
@@ -328,14 +344,24 @@ void guac_rdpdr_process_server_capability(guac_rdp_common_svc* svc,
         int type;
         int length;
 
-        if (Stream_GetRemainingLength(input_stream) < 4)
+        /* Make sure Stream has at least 4 bytes (UINT16 + UINT16) */
+        if (Stream_GetRemainingLength(input_stream) < 4) {
+            guac_client_log(svc->client, GUAC_LOG_WARNING, "Redirection Stream "
+                    "does not contain the expected number of bytes. Device "
+                    "redirection may not work as expected.");
             break;
+        }
         
         Stream_Read_UINT16(input_stream, type);
         Stream_Read_UINT16(input_stream, length);
 
-        if (Stream_GetRemainingLength(input_stream) < (length - 4))
+        /* Make sure Stream has required length remaining for Seek below. */
+        if (Stream_GetRemainingLength(input_stream) < (length - 4)) {
+            guac_client_log(svc->client, GUAC_LOG_WARNING, "Redirection Stream "
+                    "does not contain the expected number of bytes. Device "
+                    "redirection may not work as expected.");
             break;
+        }
         
         /* Ignore all for now */
         guac_client_log(svc->client, GUAC_LOG_DEBUG, "Ignoring server capability set type=0x%04x, length=%i", type, length);

src/protocols/rdp/channels/rdpdr/rdpdr-printer.c

@@ -67,8 +67,13 @@ void guac_rdpdr_process_print_job_write(guac_rdp_common_svc* svc,
     int length;
     int status;
 
-    if (Stream_GetRemainingLength(input_stream) < 32)
+    /* Verify that Stream contains at least 32 bytes (UINT32 + 8 + 20) */
+    if (Stream_GetRemainingLength(input_stream) < 32) {
+        guac_client_log(client, GUAC_LOG_WARNING, "Printer Stream does not "
+                "contain the required number of bytes. Print redirection may "
+                "not work as expected.");
         return;
+    }
     
     /* Read buffer of print data */
     Stream_Read_UINT32(input_stream, length);

src/protocols/rdp/channels/rdpdr/rdpdr.c

@@ -38,8 +38,16 @@ void guac_rdpdr_process_receive(guac_rdp_common_svc* svc,
     int component;
     int packet_id;
 
-    if (Stream_GetRemainingLength(input_stream) < 4)
+    /* 
+     * Check that device redirection stream contains at least 4 bytes
+     * (UINT16 + UINT16).
+     */
+    if (Stream_GetRemainingLength(input_stream) < 4) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Device redirection "
+                "Stream does not contain the required number of bytes. Device "
+                "redirection may not function as expected.");
         return;
+    }
     
     /* Read header */
     Stream_Read_UINT16(input_stream, component);

src/protocols/rdp/channels/rdpsnd/rdpsnd-messages.c

@@ -50,8 +50,13 @@ void guac_rdpsnd_formats_handler(guac_rdp_common_svc* svc,
     /* Reset own format count */
     rdpsnd->format_count = 0;
 
-    if (Stream_GetRemainingLength(input_stream) < 20)
+    /* Check to make sure the stream has at least 20 bytes, which */
+    if (Stream_GetRemainingLength(input_stream) < 20) {
+        guac_client_log(client, GUAC_LOG_WARNING, "Audio Stream does not "
+                "contain the expected number of bytes. Sound may not work as "
+                "expected.");
         return;
+    }
     
     /* Format header */
     Stream_Seek(input_stream, 14);
@@ -99,8 +104,13 @@ void guac_rdpsnd_formats_handler(guac_rdp_common_svc* svc,
             /* Remember position in stream */
             Stream_GetPointer(input_stream, format_start);
 
-            if (Stream_GetRemainingLength(input_stream) < 18)
+            /* Check to make sure Stream has at least 18 bytes. */
+            if (Stream_GetRemainingLength(input_stream) < 18) {
+                guac_client_log(client, GUAC_LOG_WARNING, "Audio Stream does "
+                        "not contain the expected number of bytes. Sound may "
+                        "not work as expected.");
                 return;
+            }
             
             /* Read format */
             Stream_Read_UINT16(input_stream, format_tag);
@@ -113,8 +123,13 @@ void guac_rdpsnd_formats_handler(guac_rdp_common_svc* svc,
             /* Skip past extra data */
             Stream_Read_UINT16(input_stream, body_size);
             
-            if (Stream_GetRemainingLength(input_stream) < body_size)
+            /* Check that Stream has at least body_size bytes remaining. */
+            if (Stream_GetRemainingLength(input_stream) < body_size) {
+                guac_client_log(client, GUAC_LOG_WARNING, "Audio Stream does "
+                        "not contain the expected number of bytes. Sound may "
+                        "not work as expected.");
                 return;
+            }
             
             Stream_Seek(input_stream, body_size);
 
@@ -215,8 +230,13 @@ void guac_rdpsnd_training_handler(guac_rdp_common_svc* svc,
 
     guac_rdpsnd* rdpsnd = (guac_rdpsnd*) svc->data;
 
-    if (Stream_GetRemainingLength(input_stream) < 4)
+    /* Check to make sure audio stream contains a minimum number of bytes. */
+    if (Stream_GetRemainingLength(input_stream) < 4) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Audio Stream does not "
+                "contain the expected number of bytes. Sound may not work as "
+                "expected.");
         return;
+    }
     
     /* Read timestamp and data size */
     Stream_Read_UINT16(input_stream, rdpsnd->server_timestamp);
@@ -245,8 +265,13 @@ void guac_rdpsnd_wave_info_handler(guac_rdp_common_svc* svc,
     guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
     guac_audio_stream* audio = rdp_client->audio;
 
-    if (Stream_GetRemainingLength(input_stream) < 12)
+    /* Check to make sure audio stream contains a minimum number of bytes. */
+    if (Stream_GetRemainingLength(input_stream) < 12) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Audio stream does not "
+                "contain the expected number of bytes. Sound may not work as "
+                "expected.");
         return;
+    }
     
     /* Read wave information */
     Stream_Read_UINT16(input_stream, rdpsnd->server_timestamp);

src/protocols/rdp/channels/rdpsnd/rdpsnd.c

@@ -35,9 +35,13 @@ void guac_rdpsnd_process_receive(guac_rdp_common_svc* svc,
     guac_rdpsnd* rdpsnd = (guac_rdpsnd*) svc->data;
     guac_rdpsnd_pdu_header header;
 
-    /* Check that we at least have a header. */
+    /* Check that we at least the 4 byte header (UINT8 + UINT8 + UINT16) */
-    if (Stream_GetRemainingLength(input_stream) < 4)
+    if (Stream_GetRemainingLength(input_stream) < 4) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Audio Stream does not "
+                "contain the expected number of bytes. Sound may not work as "
+                "expected.");
         return;
+    }
     
     /* Read RDPSND PDU header */
     Stream_Read_UINT8(input_stream, header.message_type);
@@ -53,9 +57,13 @@ void guac_rdpsnd_process_receive(guac_rdp_common_svc* svc,
         return;
     }
     
-    /* Check body size */
+    /* Check Stream size against body size */
-    if (Stream_GetRemainingLength(input_stream) < header.body_size)
+    if (Stream_GetRemainingLength(input_stream) < header.body_size) {
+        guac_client_log(svc->client, GUAC_LOG_WARNING, "Audio Stream does not "
+                "contain the expected number of bytes. Sound may not work as "
+                "expected.");
         return;
+    }
 
     /* Dispatch message to standard handlers */
     switch (header.message_type) {

src/protocols/rdp/plugins/guacai/guacai-messages.c

@@ -39,6 +39,7 @@
 static void guac_rdp_ai_read_format(wStream* stream,
         guac_rdp_ai_format* format) {
 
+    /* Check that we have at least 18 bytes (5 x UINT16, 2 x UINT32) */
     if (Stream_GetRemainingLength(stream) < 18)
         return;
     
@@ -51,7 +52,7 @@ static void guac_rdp_ai_read_format(wStream* stream,
     Stream_Read_UINT16(stream, format->bps); /* wBitsPerSample */
     Stream_Read_UINT16(stream, format->data_size); /* cbSize */
 
-    /* Read arbitrary data block (if applicable) */
+    /* Read arbitrary data block (if applicable) and data is available. */
     if (format->data_size != 0
             && Stream_GetRemainingLength(stream) >= format->data_size) {
         format->data = Stream_Pointer(stream); /* data */
@@ -236,9 +237,11 @@ static void guac_rdp_ai_send_formatchange(IWTSVirtualChannel* channel,
 void guac_rdp_ai_process_version(guac_client* client,
         IWTSVirtualChannel* channel, wStream* stream) {
 
+    /* Verify we have at least 4 bytes available (UINT32) */
     if (Stream_GetRemainingLength(stream) < 4) {
-        guac_client_log(client, GUAC_LOG_WARNING,
+        guac_client_log(client, GUAC_LOG_WARNING, "Audio input stream does not "
-                "Invalid value provided for AUDIO_INPUT version.");
+                "contain the expected number of bytes. Audio input may not "
+                "work as expected.");
         return;
     }
     
@@ -268,8 +271,13 @@ void guac_rdp_ai_process_formats(guac_client* client,
     guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
     guac_rdp_audio_buffer* audio_buffer = rdp_client->audio_input;
 
-    if (Stream_GetRemainingLength(stream) < 8)
+    /* Verify we have at least 8 bytes available (2 x UINT32) */
+    if (Stream_GetRemainingLength(stream) < 8) {
+        guac_client_log(client, GUAC_LOG_WARNING, "Audio input stream does not "
+                "contain the expected number of bytes. Audio input may not "
+                "work as expected.");
         return;
+    }
     
     UINT32 num_formats;
     Stream_Read_UINT32(stream, num_formats); /* NumFormats */
@@ -319,8 +327,13 @@ void guac_rdp_ai_process_open(guac_client* client,
     guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
     guac_rdp_audio_buffer* audio_buffer = rdp_client->audio_input;
 
-    if (Stream_GetRemainingLength(stream) < 8)
+    /* Verify we have at least 8 bytes available (2 x UINT32) */
+    if (Stream_GetRemainingLength(stream) < 8) {
+        guac_client_log(client, GUAC_LOG_WARNING, "Audio input stream does not "
+                "contain the expected number of bytes. Audio input may not "
+                "work as expected.");
         return;
+    }
     
     UINT32 packet_frames;
     UINT32 initial_format;

src/protocols/rdp/plugins/guacai/guacai.c

@@ -52,8 +52,13 @@
 static void guac_rdp_ai_handle_data(guac_client* client,
         IWTSVirtualChannel* channel, wStream* stream) {
 
-    if (Stream_GetRemainingLength(stream) < 1)
+    /* Verify we have at least 1 byte in the stream (UINT8) */
+    if (Stream_GetRemainingLength(stream) < 1) {
+        guac_client_log(client, GUAC_LOG_WARNING, "Audio input stream does not "
+                "contain the expected number of bytes. Audio input may not "
+                "work as expected.");
         return;
+    }
     
     /* Read message ID from received PDU */
     BYTE message_id;