ftp-data: fix direction for active mode commands

Set correct direction for PORT mode, where the server connects
to the client.

The direction is not also strictly enforced. No data in the wrong
direction will be accepted to setup the file or to be added to the
file after setup.

This also fixes files getting closed twice.

Adds some general cleanups.

Bug: #3542.
(cherry picked from commit 07bf9214513e54e04508c055bb8ed29aa3bce60f)

diff --git a/src/app-layer-ftp.c b/src/app-layer-ftp.c
index 4ca994fbaac4a8bd1302893e46b4ef4c56d781af..2793a7d33844dd4947d9fead1b574e9fef624694 100644 (file)
--- a/src/app-layer-ftp.c
+++ b/src/app-layer-ftp.c
@@ -539,6 +539,7 @@ struct FtpTransferCmd {
     uint64_t flow_id;
     uint8_t *file_name;
     uint16_t file_len;
+    uint8_t direction; /**< direction in which the data will flow */
     FtpRequestCommand cmd;
 };
 
@@ -693,6 +694,7 @@ static AppLayerResult FTPParseRequest(Flow *f, void *ftp_state,
                     memcpy(data->file_name, state->current_line + 5, file_name_len);
                     data->cmd = state->command;
                     data->flow_id = FlowGetId(f);
+                    data->direction = direction;
                     int ret = AppLayerExpectationCreate(f, direction,
                                             0, state->dyn_port, ALPROTO_FTPDATA, data);
                     if (ret == -1) {
@@ -1099,13 +1101,29 @@ static AppLayerResult FTPDataParse(Flow *f, FtpDataState *ftpdata_state,
     int ret = 0;
     /* we depend on detection engine for file pruning */
     flags |= FILE_USE_DETECT;
-    if (ftpdata_state->files == NULL) {
+    const bool eof = (flags & STREAM_TOSERVER)
+                             ? AppLayerParserStateIssetFlag(pstate, APP_LAYER_PARSER_EOF_TS) != 0
+                             : AppLayerParserStateIssetFlag(pstate, APP_LAYER_PARSER_EOF_TC) != 0;
+
+    SCLogDebug("FTP-DATA input_len %u flags %04x dir %d/%s EOF %s", input_len, flags, direction,
+            (direction & STREAM_TOSERVER) ? "toserver" : "toclient", eof ? "true" : "false");
+    if (input_len && ftpdata_state->files == NULL) {
         struct FtpTransferCmd *data =
                 (struct FtpTransferCmd *)FlowGetStorageById(f, AppLayerExpectationGetFlowId());
         if (data == NULL) {
             SCReturnStruct(APP_LAYER_ERROR);
         }
 
+        /* we shouldn't get data in the wrong dir. Don't set things up for this dir */
+        if ((direction & data->direction) == 0) {
+            // TODO set event for data in wrong direction
+            SCLogDebug("input %u not for our direction (%s): %s/%s", input_len,
+                    (direction & STREAM_TOSERVER) ? "toserver" : "toclient",
+                    data->cmd == FTP_COMMAND_STOR ? "STOR" : "RETR",
+                    (data->direction & STREAM_TOSERVER) ? "toserver" : "toclient");
+            SCReturnStruct(APP_LAYER_OK);
+        }
+
         ftpdata_state->files = FileContainerAlloc();
         if (ftpdata_state->files == NULL) {
             FlowFreeStorageById(f, AppLayerExpectationGetFlowId());
@@ -1120,10 +1138,14 @@ static AppLayerResult FTPDataParse(Flow *f, FtpDataState *ftpdata_state,
         ftpdata_state->command = data->cmd;
         switch (data->cmd) {
             case FTP_COMMAND_STOR:
-                ftpdata_state->direction = STREAM_TOSERVER;
+                ftpdata_state->direction = data->direction;
+                SCLogDebug("STOR data to %s",
+                        (ftpdata_state->direction & STREAM_TOSERVER) ? "toserver" : "toclient");
                 break;
             case FTP_COMMAND_RETR:
-                ftpdata_state->direction = STREAM_TOCLIENT;
+                ftpdata_state->direction = data->direction;
+                SCLogDebug("RETR data to %s",
+                        (ftpdata_state->direction & STREAM_TOSERVER) ? "toserver" : "toclient");
                 break;
             default:
                 break;
@@ -1141,6 +1163,21 @@ static AppLayerResult FTPDataParse(Flow *f, FtpDataState *ftpdata_state,
         FlowFreeStorageById(f, AppLayerExpectationGetFlowId());
         ftpdata_state->tx_data.files_opened = 1;
     } else {
+        if (ftpdata_state->state == FTPDATA_STATE_FINISHED) {
+            SCLogDebug("state is already finished");
+            DEBUG_VALIDATE_BUG_ON(input_len); // data after state finished is a bug.
+            SCReturnStruct(APP_LAYER_OK);
+        }
+        if ((direction & ftpdata_state->direction) == 0) {
+            if (input_len) {
+                // TODO set event for data in wrong direction
+            }
+            SCLogDebug("input %u not for us (%s): %s/%s", input_len,
+                    (direction & STREAM_TOSERVER) ? "toserver" : "toclient",
+                    ftpdata_state->command == FTP_COMMAND_STOR ? "STOR" : "RETR",
+                    (ftpdata_state->direction & STREAM_TOSERVER) ? "toserver" : "toclient");
+            SCReturnStruct(APP_LAYER_OK);
+        }
         if (input_len != 0) {
             ret = FileAppendData(ftpdata_state->files, input, input_len);
             if (ret == -2) {
@@ -1152,22 +1189,15 @@ static AppLayerResult FTPDataParse(Flow *f, FtpDataState *ftpdata_state,
                 ret = -2;
                 goto out;
             }
-        } else {
-            ret = FileCloseFile(ftpdata_state->files, NULL, 0, flags);
-            ftpdata_state->state = FTPDATA_STATE_FINISHED;
-            if (ret < 0)
-                goto out;
         }
     }
 
-    const bool eof_flag = flags & STREAM_TOSERVER ?
-        AppLayerParserStateIssetFlag(pstate, APP_LAYER_PARSER_EOF_TS) != 0 :
-        AppLayerParserStateIssetFlag(pstate, APP_LAYER_PARSER_EOF_TC) != 0;
-    if (input_len && eof_flag) {
-        ret = FileCloseFile(ftpdata_state->files, (uint8_t *) NULL, 0, flags);
+    BUG_ON((direction & ftpdata_state->direction) == 0); // should be unreachble
+    if (eof) {
+        ret = FileCloseFile(ftpdata_state->files, NULL, 0, flags);
         ftpdata_state->state = FTPDATA_STATE_FINISHED;
+        SCLogDebug("closed because of eof");
     }
-
 out:
     if (ret < 0) {
         SCReturnStruct(APP_LAYER_ERROR);
@@ -1283,7 +1313,10 @@ static int FTPDataGetAlstateProgressCompletionStatus(uint8_t direction)
 static int FTPDataGetAlstateProgress(void *tx, uint8_t direction)
 {
     FtpDataState *ftpdata_state = (FtpDataState *)tx;
-    return ftpdata_state->state;
+    if (direction == ftpdata_state->direction)
+        return ftpdata_state->state;
+    else
+        return FTPDATA_STATE_FINISHED;
 }
 
 static FileContainer *FTPDataStateGetFiles(void *state, uint8_t direction)