Qt: fix several crashes in the SCTP Dialogs

Store the association id instead of a pointer to the volatile
"sctp_assoc_info_t" structure because it gets freed after a rescan.

Bug: 14970
Change-Id: Id8fe2dfe3549bd711fc8ddef0770b217e83c2088
Fixes: v1.11.3-rc1-604-g796bf409b0 ("Add dialogs and graphs to analyse SCTP behavior similar to the GTK version.")
Reviewed-on: https://code.wireshark.org/review/28711
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

15 files changed, 173 insertions, 140 deletions

diff --git a/ui/qt/main_window_slots.cpp b/ui/qt/main_window_slots.cpp
index 4dfb0f468b..ef03920384 100644
--- a/ui/qt/main_window_slots.cpp
+++ b/ui/qt/main_window_slots.cpp
@@ -2815,7 +2815,11 @@ void MainWindow::on_actionSCTPShowAllAssociations_triggered()
 
 void MainWindow::on_actionSCTPAnalyseThisAssociation_triggered()
 {
-    SCTPAssocAnalyseDialog *sctp_analyse = new SCTPAssocAnalyseDialog(this, NULL, capture_file_.capFile());
+    const sctp_assoc_info_t* assoc = SCTPAssocAnalyseDialog::findAssocForPacket(capture_file_.capFile());
+    if (!assoc) {
+        return;
+    }
+    SCTPAssocAnalyseDialog *sctp_analyse = new SCTPAssocAnalyseDialog(this, assoc, capture_file_.capFile());
     connect(sctp_analyse, SIGNAL(filterPackets(QString,bool)),
             this, SLOT(filterPackets(QString,bool)));
 
@@ -2834,7 +2838,7 @@ void MainWindow::on_actionSCTPAnalyseThisAssociation_triggered()
 
 void MainWindow::on_actionSCTPFilterThisAssociation_triggered()
 {
-    sctp_assoc_info_t* assoc = SCTPAssocAnalyseDialog::findAssocForPacket(capture_file_.capFile());
+    const sctp_assoc_info_t* assoc = SCTPAssocAnalyseDialog::findAssocForPacket(capture_file_.capFile());
     if (assoc) {
         QString newFilter = QString("sctp.assoc_index==%1").arg(assoc->assoc_id);
         assoc = NULL;
diff --git a/ui/qt/sctp_all_assocs_dialog.cpp b/ui/qt/sctp_all_assocs_dialog.cpp
index 15bd635f1f..6f9646a909 100644
--- a/ui/qt/sctp_all_assocs_dialog.cpp
+++ b/ui/qt/sctp_all_assocs_dialog.cpp
@@ -44,7 +44,7 @@ SCTPAllAssocsDialog::~SCTPAllAssocsDialog()
 void SCTPAllAssocsDialog::fillTable()
 {
     GList *list;
-    sctp_assoc_info_t* assinfo;
+    const sctp_assoc_info_t* assinfo;
     int numAssocs;
 
     ui->assocList->setColumnHidden(0, true);
@@ -54,7 +54,7 @@ void SCTPAllAssocsDialog::fillTable()
     ui->assocList->setColumnWidth(4,  150);
 
     sctp_assocs = (sctp_allassocs_info_t*)sctp_stat_get_info();
-    if (sctp_stat_get_info()->is_registered == FALSE) {
+    if (sctp_assocs->is_registered == FALSE) {
         register_tap_listener_sctp_stat();
         /*  (redissect all packets) */
         cf_retap_packets(cap_file_);
@@ -65,7 +65,7 @@ void SCTPAllAssocsDialog::fillTable()
     list = g_list_first(sctp_assocs->assoc_info_list);
 
     while (list) {
-        assinfo = (sctp_assoc_info_t*)(list->data);
+        assinfo = (const sctp_assoc_info_t*)(list->data);
         ui->assocList->setItem(numAssocs, 0, new QTableWidgetItem(QString("%1").arg(assinfo->assoc_id)));
         ui->assocList->setItem(numAssocs, 1, new QTableWidgetItem(QString("%1").arg(assinfo->port1)));
         ui->assocList->setItem(numAssocs, 2, new QTableWidgetItem(QString("%1").arg(assinfo->port2)));
@@ -80,45 +80,20 @@ void SCTPAllAssocsDialog::fillTable()
     connect(ui->assocList, SIGNAL(itemSelectionChanged()), this, SLOT(getSelectedItem()));
  }
 
-sctp_assoc_info_t* SCTPAllAssocsDialog::findSelectedAssoc()
-{
-    QTableWidgetItem *selection;
-    GList *list;
-    sctp_assoc_info_t* assinfo;
-    int row, id;
-
-    selection = ui->assocList->selectedItems()[0];
-    row = selection->row();
-    selection = ui->assocList->item(row, 0);
-    id = (selection->data(0)).toInt();
-    list = g_list_first(sctp_assocs->assoc_info_list);
-
-    while (list) {
-        assinfo = (sctp_assoc_info_t*)(list->data);
-        if (assinfo->assoc_id == id) {
-            return assinfo;
-        }
-        list = g_list_next(list);
-    }
-    return NULL;
-}
-
 void SCTPAllAssocsDialog::getSelectedItem()
 {
     ui->analyseButton->setEnabled(true);
     ui->setFilterButton->setEnabled(true);
     ui->analyseButton->setFocus(Qt::OtherFocusReason);
-    selected_assoc = findSelectedAssoc();
+    selected_assoc_id = ui->assocList->item(ui->assocList->selectedItems().at(0)->row(), 0)->data(0).toInt();
 }
 
 void SCTPAllAssocsDialog::on_analyseButton_clicked()
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
 
-    if (!selected_assoc) {
-        selected_assoc = findSelectedAssoc();
-    }
-
-    SCTPAssocAnalyseDialog *sctp_analyse = new SCTPAssocAnalyseDialog(this, selected_assoc, cap_file_, this);
+    SCTPAssocAnalyseDialog *sctp_analyse = new SCTPAssocAnalyseDialog(this, selected_assoc, cap_file_);
     connect(sctp_analyse, SIGNAL(filterPackets(QString&,bool)),
             parent(), SLOT(filterPackets(QString&,bool)));
 
@@ -137,13 +112,7 @@ void SCTPAllAssocsDialog::on_analyseButton_clicked()
 
 void SCTPAllAssocsDialog::on_setFilterButton_clicked()
 {
-
-    if (!selected_assoc){
-        selected_assoc = findSelectedAssoc();
-    }
-
-    QString newFilter = QString("sctp.assoc_index==%1").arg(selected_assoc->assoc_id);
-    selected_assoc = NULL;
+    QString newFilter = QString("sctp.assoc_index==%1").arg(selected_assoc_id);
     emit filterPackets(newFilter, false);
 }
 
diff --git a/ui/qt/sctp_all_assocs_dialog.h b/ui/qt/sctp_all_assocs_dialog.h
index 094cacf965..7c6a106910 100644
--- a/ui/qt/sctp_all_assocs_dialog.h
+++ b/ui/qt/sctp_all_assocs_dialog.h
@@ -36,8 +36,6 @@ public:
     ~SCTPAllAssocsDialog();
 
     void fillTable();
-    sctp_assoc_info_t* getSelectedAssoc() { return selected_assoc; }
-    sctp_assoc_info_t* findSelectedAssoc();
 
 public slots:
     void setCaptureFile(capture_file *cf) { cap_file_ = cf; }
@@ -51,7 +49,7 @@ private:
     Ui::SCTPAllAssocsDialog *ui;
     capture_file *cap_file_;
     sctp_allassocs_info_t *sctp_assocs;
-    sctp_assoc_info_t     *selected_assoc;
+    guint16 selected_assoc_id;
 
 
 signals:
diff --git a/ui/qt/sctp_assoc_analyse_dialog.cpp b/ui/qt/sctp_assoc_analyse_dialog.cpp
index b965c94241..9d401a0961 100644
--- a/ui/qt/sctp_assoc_analyse_dialog.cpp
+++ b/ui/qt/sctp_assoc_analyse_dialog.cpp
@@ -18,29 +18,25 @@
 #include "sctp_graph_byte_dialog.h"
 #include "sctp_chunk_statistics_dialog.h"
 
-SCTPAssocAnalyseDialog::SCTPAssocAnalyseDialog(QWidget *parent, sctp_assoc_info_t *assoc, capture_file *cf, SCTPAllAssocsDialog* caller) :
+SCTPAssocAnalyseDialog::SCTPAssocAnalyseDialog(QWidget *parent, const sctp_assoc_info_t *assoc,
+        capture_file *cf) :
     QDialog(parent),
     ui(new Ui::SCTPAssocAnalyseDialog),
-    selected_assoc(assoc),
-    cap_file_(cf),
-    caller_(caller)
+    cap_file_(cf)
 {
+    Q_ASSERT(assoc);
+    selected_assoc_id = assoc->assoc_id;
+
     ui->setupUi(this);
     ui->SCTPAssocAnalyseTab->setCurrentWidget(ui->Statistics);
-    if (!selected_assoc) {
-        if (sctp_stat_get_info()->is_registered == FALSE) {
-            register_tap_listener_sctp_stat();
-        }
-        /*  (redissect all packets) */
-        cf_retap_packets(cap_file_);
-        selected_assoc = findAssocForPacket(cap_file_);
-    }
     Qt::WindowFlags flags = Qt::Window | Qt::WindowSystemMenuHint
             | Qt::WindowMinimizeButtonHint
             | Qt::WindowCloseButtonHint;
     this->setWindowFlags(flags);
-    this->setWindowTitle(QString(tr("SCTP Analyse Association: %1 Port1 %2 Port2 %3")).arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(selected_assoc->port1).arg(selected_assoc->port2));
-    fillTabs();
+
+    this->setWindowTitle(QString(tr("SCTP Analyse Association: %1 Port1 %2 Port2 %3"))
+            .arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(assoc->port1).arg(assoc->port2));
+    fillTabs(assoc);
 }
 
 SCTPAssocAnalyseDialog::~SCTPAssocAnalyseDialog()
@@ -48,11 +44,11 @@ SCTPAssocAnalyseDialog::~SCTPAssocAnalyseDialog()
     delete ui;
 }
 
-sctp_assoc_info_t* SCTPAssocAnalyseDialog::findAssocForPacket(capture_file* cf)
+const sctp_assoc_info_t* SCTPAssocAnalyseDialog::findAssocForPacket(capture_file* cf)
 {
     frame_data     *fdata;
     GList          *list, *framelist;
-    sctp_assoc_info_t *assoc;
+    const sctp_assoc_info_t *assoc;
     bool           frame_found = false;
 
     fdata = cf->current_frame;
@@ -64,7 +60,7 @@ sctp_assoc_info_t* SCTPAssocAnalyseDialog::findAssocForPacket(capture_file* cf)
     list = g_list_first(sctp_stat_get_info()->assoc_info_list);
 
     while (list) {
-        assoc = (sctp_assoc_info_t*)(list->data);
+        assoc = (const sctp_assoc_info_t*)(list->data);
 
         framelist = g_list_first(assoc->frame_numbers);
         guint32 fn;
@@ -91,8 +87,20 @@ sctp_assoc_info_t* SCTPAssocAnalyseDialog::findAssocForPacket(capture_file* cf)
     return NULL;
 }
 
-void SCTPAssocAnalyseDialog::fillTabs()
+const _sctp_assoc_info* SCTPAssocAnalyseDialog::findAssoc(QWidget *parent, guint16 assoc_id)
+{
+    const sctp_assoc_info_t* result = get_sctp_assoc_info(assoc_id);
+    if (result) return result;
+
+    QMessageBox::warning(parent, tr("Warning"), tr("Could not find SCTP Association with id: %1")
+            .arg(assoc_id));
+    return NULL;
+}
+
+void SCTPAssocAnalyseDialog::fillTabs(const sctp_assoc_info_t* selected_assoc)
 {
+    Q_ASSERT(selected_assoc);
+
     /* Statistics Tab */
 
     ui->checksumLabel->setText(selected_assoc->checksum_type);
@@ -209,6 +217,9 @@ void SCTPAssocAnalyseDialog::fillTabs()
 
 void SCTPAssocAnalyseDialog::openGraphDialog(int direction)
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     SCTPGraphDialog *sctp_dialog = new SCTPGraphDialog(this, selected_assoc, cap_file_, direction);
 
     if (sctp_dialog->isMinimized() == true) {
@@ -235,11 +246,9 @@ void SCTPAssocAnalyseDialog::on_GraphTSN_1_clicked()
 
 void SCTPAssocAnalyseDialog::on_chunkStatisticsButton_clicked()
 {
-    if (caller_ && !selected_assoc) {
-        selected_assoc = caller_->findSelectedAssoc();
-    } else if (!caller_ && !selected_assoc) {
-        selected_assoc = findAssocForPacket(cap_file_);
-    }
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     SCTPChunkStatisticsDialog *sctp_dialog = new SCTPChunkStatisticsDialog(this, selected_assoc, cap_file_);
 
     if (sctp_dialog->isMinimized() == true) {
@@ -254,13 +263,15 @@ void SCTPAssocAnalyseDialog::on_chunkStatisticsButton_clicked()
 
 void SCTPAssocAnalyseDialog::on_setFilterButton_clicked()
 {
-    QString newFilter = QString("sctp.assoc_index==%1").arg(selected_assoc->assoc_id);
-    selected_assoc = NULL;
+    QString newFilter = QString("sctp.assoc_index==%1").arg(selected_assoc_id);
     emit filterPackets(newFilter, false);
 }
 
 void SCTPAssocAnalyseDialog::openGraphByteDialog(int direction)
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     SCTPGraphByteDialog *sctp_dialog = new SCTPGraphByteDialog(this, selected_assoc, cap_file_, direction);
 
     if (sctp_dialog->isMinimized() == true) {
@@ -285,6 +296,9 @@ void SCTPAssocAnalyseDialog::on_GraphBytes_2_clicked()
 
 void SCTPAssocAnalyseDialog::openGraphArwndDialog(int direction)
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     SCTPGraphArwndDialog *sctp_dialog = new SCTPGraphArwndDialog(this, selected_assoc, cap_file_, direction);
 
     if (sctp_dialog->isMinimized() == true) {
diff --git a/ui/qt/sctp_assoc_analyse_dialog.h b/ui/qt/sctp_assoc_analyse_dialog.h
index d893c9dcb1..8f46729836 100644
--- a/ui/qt/sctp_assoc_analyse_dialog.h
+++ b/ui/qt/sctp_assoc_analyse_dialog.h
@@ -18,7 +18,6 @@
 
 #include <epan/dissectors/packet-sctp.h>
 
-#include "ui/tap-sctp-analysis.h"
 #include "sctp_all_assocs_dialog.h"
 
 #include <QDialog>
@@ -32,16 +31,20 @@ namespace Ui {
 class SCTPAssocAnalyseDialog;
 }
 
+struct _sctp_assoc_info;
+
 class SCTPAssocAnalyseDialog : public QDialog
 {
     Q_OBJECT
 
 public:
-    explicit SCTPAssocAnalyseDialog(QWidget *parent = 0, sctp_assoc_info_t *assoc = NULL, capture_file *cf = NULL, SCTPAllAssocsDialog *caller = NULL);
+    explicit SCTPAssocAnalyseDialog(QWidget *parent = 0, const _sctp_assoc_info *assoc = NULL,
+            capture_file *cf = NULL);
     ~SCTPAssocAnalyseDialog();
 
-    void fillTabs();
-    static sctp_assoc_info_t* findAssocForPacket(capture_file* cf);
+    void fillTabs(const _sctp_assoc_info* selected_assoc);
+    static const _sctp_assoc_info* findAssocForPacket(capture_file* cf);
+    static const _sctp_assoc_info* findAssoc(QWidget *parent, guint16 assoc_id);
 
 public slots:
     void setCaptureFile(capture_file *cf) { cap_file_ = cf; }
@@ -60,9 +63,8 @@ private slots:
 
 private:
     Ui::SCTPAssocAnalyseDialog *ui;
-    sctp_assoc_info_t     *selected_assoc;
+    guint16 selected_assoc_id;
     capture_file *cap_file_;
-    SCTPAllAssocsDialog *caller_;
     void openGraphDialog(int direction);
     void openGraphByteDialog(int direction);
     void openGraphArwndDialog(int direction);
diff --git a/ui/qt/sctp_chunk_statistics_dialog.cpp b/ui/qt/sctp_chunk_statistics_dialog.cpp
index 08496f6a29..e2f37a8011 100644
--- a/ui/qt/sctp_chunk_statistics_dialog.cpp
+++ b/ui/qt/sctp_chunk_statistics_dialog.cpp
@@ -8,19 +8,24 @@
  */
 
 #include "sctp_chunk_statistics_dialog.h"
+#include "sctp_assoc_analyse_dialog.h"
 #include <ui_sctp_chunk_statistics_dialog.h>
 #include "uat_dialog.h"
 
 #include <wsutil/strtoi.h>
 
+#include "ui/tap-sctp-analysis.h"
 #include <ui/qt/utils/qt_ui_utils.h>
 
-SCTPChunkStatisticsDialog::SCTPChunkStatisticsDialog(QWidget *parent, sctp_assoc_info_t *assoc, capture_file *cf) :
+SCTPChunkStatisticsDialog::SCTPChunkStatisticsDialog(QWidget *parent, const sctp_assoc_info_t *assoc,
+        capture_file *cf) :
     QDialog(parent),
     ui(new Ui::SCTPChunkStatisticsDialog),
-    selected_assoc(assoc),
     cap_file_(cf)
 {
+    Q_ASSERT(assoc);
+    selected_assoc_id = assoc->assoc_id;
+
     ui->setupUi(this);
     Qt::WindowFlags flags = Qt::Window | Qt::WindowSystemMenuHint
             | Qt::WindowMinimizeButtonHint
@@ -36,14 +41,16 @@ SCTPChunkStatisticsDialog::SCTPChunkStatisticsDialog(QWidget *parent, sctp_assoc
 
     ui->tableWidget->horizontalHeader()->setSectionResizeMode(QHeaderView::ResizeToContents);
 
-    this->setWindowTitle(QString(tr("SCTP Chunk Statistics: %1 Port1 %2 Port2 %3")).arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(selected_assoc->port1).arg(selected_assoc->port2));
+    this->setWindowTitle(QString(tr("SCTP Chunk Statistics: %1 Port1 %2 Port2 %3"))
+            .arg(gchar_free_to_qstring(cf_get_display_name(cap_file_)))
+            .arg(assoc->port1).arg(assoc->port2));
  //   connect(ui->tableWidget->verticalHeader(), SIGNAL(sectionMoved(int,int,int)), this, SLOT(on_sectionMoved(int, int, int)));
 
     ctx_menu_.addAction(ui->actionHideChunkType);
     ctx_menu_.addAction(ui->actionChunkTypePreferences);
     ctx_menu_.addAction(ui->actionShowAllChunkTypes);
     initializeChunkMap();
-    fillTable();
+    fillTable(false, assoc);
 }
 
 SCTPChunkStatisticsDialog::~SCTPChunkStatisticsDialog()
@@ -71,8 +78,13 @@ void SCTPChunkStatisticsDialog::initializeChunkMap()
     }
 }
 
-void SCTPChunkStatisticsDialog::fillTable(bool all)
+void SCTPChunkStatisticsDialog::fillTable(bool all, const sctp_assoc_info_t *selected_assoc)
 {
+    if (!selected_assoc) {
+        selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+        if (!selected_assoc) return;
+    }
+
     FILE* fp = NULL;
 
     pref_t *pref = prefs_find_preference(prefs_find_module("sctp"),"statistics_chunk_types");
diff --git a/ui/qt/sctp_chunk_statistics_dialog.h b/ui/qt/sctp_chunk_statistics_dialog.h
index 3fdb2aae1f..09e254b6fd 100644
--- a/ui/qt/sctp_chunk_statistics_dialog.h
+++ b/ui/qt/sctp_chunk_statistics_dialog.h
@@ -24,8 +24,6 @@
 #include <wsutil/filesystem.h>
 #include "wireshark_application.h"
 
-#include "ui/tap-sctp-analysis.h"
-
 #include <QTableWidgetItem>
 #include <QDialog>
 #include <QMenu>
@@ -35,12 +33,14 @@ namespace Ui {
 class SCTPChunkStatisticsDialog;
 }
 
+struct _sctp_assoc_info;
+
 class SCTPChunkStatisticsDialog : public QDialog
 {
     Q_OBJECT
 
 public:
-    explicit SCTPChunkStatisticsDialog(QWidget *parent = 0, sctp_assoc_info_t *assoc = NULL, capture_file *cf = NULL);
+    explicit SCTPChunkStatisticsDialog(QWidget *parent = 0, const _sctp_assoc_info *assoc = NULL, capture_file *cf = NULL);
     ~SCTPChunkStatisticsDialog();
 
 public slots:
@@ -62,7 +62,7 @@ signals:
 
 private:
     Ui::SCTPChunkStatisticsDialog *ui;
-    sctp_assoc_info_t     *selected_assoc;
+    guint16 selected_assoc_id;
     capture_file *cap_file_;
     QMenu ctx_menu_;
     QPoint selected_point;
@@ -77,7 +77,7 @@ private:
     QMap<int, struct chunkTypes> chunks, tempChunks;
 
     void initializeChunkMap();
-    void fillTable(bool all = false);
+    void fillTable(bool all = false, const _sctp_assoc_info *selected_assoc = NULL);
 };
 
 #endif // SCTP_CHUNK_STATISTICS_DIALOG_H
diff --git a/ui/qt/sctp_graph_arwnd_dialog.cpp b/ui/qt/sctp_graph_arwnd_dialog.cpp
index 18a6d35b2f..a1de32e669 100644
--- a/ui/qt/sctp_graph_arwnd_dialog.cpp
+++ b/ui/qt/sctp_graph_arwnd_dialog.cpp
@@ -22,32 +22,33 @@
 #include <ui/qt/widgets/qcustomplot.h>
 #include "sctp_graph_dialog.h"
 
-SCTPGraphArwndDialog::SCTPGraphArwndDialog(QWidget *parent, sctp_assoc_info_t *assoc, _capture_file *cf, int dir) :
+SCTPGraphArwndDialog::SCTPGraphArwndDialog(QWidget *parent, const sctp_assoc_info_t *assoc,
+        _capture_file *cf, int dir) :
     QDialog(parent),
     ui(new Ui::SCTPGraphArwndDialog),
-    selected_assoc(assoc),
     cap_file_(cf),
     frame_num(0),
     direction(dir),
     startArwnd(0)
 {
+    Q_ASSERT(assoc);
+    selected_assoc_id = assoc->assoc_id;
+
     ui->setupUi(this);
-    if (!selected_assoc) {
-        selected_assoc = SCTPAssocAnalyseDialog::findAssocForPacket(cap_file_);
-    }
     Qt::WindowFlags flags = Qt::Window | Qt::WindowSystemMenuHint
             | Qt::WindowMinimizeButtonHint
             | Qt::WindowMaximizeButtonHint
             | Qt::WindowCloseButtonHint;
     this->setWindowFlags(flags);
-    this->setWindowTitle(QString(tr("SCTP Data and Adv. Rec. Window over Time: %1 Port1 %2 Port2 %3")).arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(selected_assoc->port1).arg(selected_assoc->port2));
-    if ((direction == 1 && selected_assoc->n_array_tsn1 == 0) || (direction == 2 && selected_assoc->n_array_tsn2 == 0)) {
+    this->setWindowTitle(QString(tr("SCTP Data and Adv. Rec. Window over Time: %1 Port1 %2 Port2 %3"))
+            .arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(assoc->port1).arg(assoc->port2));
+    if ((direction == 1 && assoc->n_array_tsn1 == 0) || (direction == 2 && assoc->n_array_tsn2 == 0)) {
         QMessageBox msgBox;
         msgBox.setText(tr("No Data Chunks sent"));
         msgBox.exec();
         return;
     } else {
-        drawGraph();
+        drawGraph(assoc);
     }
 }
 
@@ -56,7 +57,7 @@ SCTPGraphArwndDialog::~SCTPGraphArwndDialog()
     delete ui;
 }
 
-void SCTPGraphArwndDialog::drawArwndGraph()
+void SCTPGraphArwndDialog::drawArwndGraph(const sctp_assoc_info_t *selected_assoc)
 {
     GList *listSACK = NULL, *tlist;
     struct sack_chunk_header *sack_header;
@@ -126,10 +127,10 @@ void SCTPGraphArwndDialog::drawArwndGraph()
 }
 
 
-void SCTPGraphArwndDialog::drawGraph()
+void SCTPGraphArwndDialog::drawGraph(const sctp_assoc_info_t *selected_assoc)
 {
     ui->sctpPlot->clearGraphs();
-    drawArwndGraph();
+    drawArwndGraph(selected_assoc);
     ui->sctpPlot->setInteractions(QCP::iRangeZoom | QCP::iRangeDrag | QCP::iSelectPlottables);
     ui->sctpPlot->axisRect(0)->setRangeZoomAxes(ui->sctpPlot->xAxis, ui->sctpPlot->yAxis);
     ui->sctpPlot->axisRect(0)->setRangeZoom(Qt::Horizontal);
@@ -140,6 +141,9 @@ void SCTPGraphArwndDialog::drawGraph()
 
 void SCTPGraphArwndDialog::on_pushButton_4_clicked()
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     ui->sctpPlot->xAxis->setRange(selected_assoc->min_secs+selected_assoc->min_usecs/1000000.0, selected_assoc->max_secs+selected_assoc->max_usecs/1000000.0);
     ui->sctpPlot->yAxis->setRange(0, startArwnd);
     ui->sctpPlot->replot();
diff --git a/ui/qt/sctp_graph_arwnd_dialog.h b/ui/qt/sctp_graph_arwnd_dialog.h
index c682014f4b..16087c4d3d 100644
--- a/ui/qt/sctp_graph_arwnd_dialog.h
+++ b/ui/qt/sctp_graph_arwnd_dialog.h
@@ -30,7 +30,8 @@ class SCTPGraphArwndDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit SCTPGraphArwndDialog(QWidget *parent = 0, struct _sctp_assoc_info *assoc = NULL, capture_file *cf = NULL, int dir = 0);
+    explicit SCTPGraphArwndDialog(QWidget *parent = 0, const _sctp_assoc_info *assoc = NULL,
+            capture_file *cf = NULL, int dir = 0);
     ~SCTPGraphArwndDialog();
 
 public slots:
@@ -45,7 +46,7 @@ private slots:
 
 private:
     Ui::SCTPGraphArwndDialog *ui;
-    struct _sctp_assoc_info *selected_assoc;
+    guint16 selected_assoc_id;
     capture_file *cap_file_;
     int frame_num;
     int direction;
@@ -54,8 +55,8 @@ private:
     QVector<guint32> fa;
  //   QVector<QString> typeStrings;
 
-    void drawGraph();
-    void drawArwndGraph();
+    void drawGraph(const _sctp_assoc_info *selected_assoc);
+    void drawArwndGraph(const _sctp_assoc_info *selected_assoc);
 };
 
 #endif // SCTP_GRAPH_DIALOG_H
diff --git a/ui/qt/sctp_graph_byte_dialog.cpp b/ui/qt/sctp_graph_byte_dialog.cpp
index 3d3753e208..7bc6b3749d 100644
--- a/ui/qt/sctp_graph_byte_dialog.cpp
+++ b/ui/qt/sctp_graph_byte_dialog.cpp
@@ -22,25 +22,26 @@
 #include "sctp_graph_dialog.h"
 #include "sctp_assoc_analyse_dialog.h"
 
-SCTPGraphByteDialog::SCTPGraphByteDialog(QWidget *parent, sctp_assoc_info_t *assoc, capture_file *cf, int dir) :
+SCTPGraphByteDialog::SCTPGraphByteDialog(QWidget *parent, const sctp_assoc_info_t *assoc,
+        capture_file *cf, int dir) :
     QDialog(parent),
     ui(new Ui::SCTPGraphByteDialog),
-    selected_assoc(assoc),
     cap_file_(cf),
     frame_num(0),
     direction(dir)
 {
+    Q_ASSERT(assoc);
+    selected_assoc_id = assoc->assoc_id;
+
     ui->setupUi(this);
-    if (!selected_assoc) {
-        selected_assoc = SCTPAssocAnalyseDialog::findAssocForPacket(cap_file_);
-    }
     Qt::WindowFlags flags = Qt::Window | Qt::WindowSystemMenuHint
             | Qt::WindowMinimizeButtonHint
             | Qt::WindowMaximizeButtonHint
             | Qt::WindowCloseButtonHint;
     this->setWindowFlags(flags);
-    this->setWindowTitle(QString(tr("SCTP Data and Adv. Rec. Window over Time: %1 Port1 %2 Port2 %3")).arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(selected_assoc->port1).arg(selected_assoc->port2));
-    if ((direction == 1 && selected_assoc->n_array_tsn1 == 0) || (direction == 2 && selected_assoc->n_array_tsn2 == 0)) {
+    this->setWindowTitle(QString(tr("SCTP Data and Adv. Rec. Window over Time: %1 Port1 %2 Port2 %3"))
+            .arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(assoc->port1).arg(assoc->port2));
+    if ((direction == 1 && assoc->n_array_tsn1 == 0) || (direction == 2 && assoc->n_array_tsn2 == 0)) {
         QMessageBox msgBox;
         msgBox.setText(tr("No Data Chunks sent"));
         msgBox.exec();
@@ -56,7 +57,7 @@ SCTPGraphByteDialog::~SCTPGraphByteDialog()
 }
 
 
-void SCTPGraphByteDialog::drawBytesGraph()
+void SCTPGraphByteDialog::drawBytesGraph(const sctp_assoc_info_t *selected_assoc)
 {
     GList *listTSN = NULL,*tlist;
     tsn_t *tsn;
@@ -126,8 +127,11 @@ void SCTPGraphByteDialog::drawBytesGraph()
 
 void SCTPGraphByteDialog::drawGraph()
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     ui->sctpPlot->clearGraphs();
-    drawBytesGraph();
+    drawBytesGraph(selected_assoc);
     ui->sctpPlot->setInteractions(QCP::iRangeZoom | QCP::iRangeDrag | QCP::iSelectPlottables);
     connect(ui->sctpPlot, SIGNAL(plottableClick(QCPAbstractPlottable*,QMouseEvent*)), this, SLOT(graphClicked(QCPAbstractPlottable*, QMouseEvent*)));
     ui->sctpPlot->replot();
@@ -136,6 +140,9 @@ void SCTPGraphByteDialog::drawGraph()
 
 void SCTPGraphByteDialog::on_pushButton_4_clicked()
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     ui->sctpPlot->xAxis->setRange(selected_assoc->min_secs+selected_assoc->min_usecs/1000000.0, selected_assoc->max_secs+selected_assoc->max_usecs/1000000.0);
     if (direction == 1) {
         ui->sctpPlot->yAxis->setRange(0, selected_assoc->n_data_bytes_ep1);
diff --git a/ui/qt/sctp_graph_byte_dialog.h b/ui/qt/sctp_graph_byte_dialog.h
index f85ade9f14..dc10ce2722 100644
--- a/ui/qt/sctp_graph_byte_dialog.h
+++ b/ui/qt/sctp_graph_byte_dialog.h
@@ -30,7 +30,8 @@ class SCTPGraphByteDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit SCTPGraphByteDialog(QWidget *parent = 0, struct _sctp_assoc_info *assoc = NULL, capture_file *cf = NULL, int dir = 0);
+    explicit SCTPGraphByteDialog(QWidget *parent = 0, const _sctp_assoc_info *assoc = NULL,
+            capture_file *cf = NULL, int dir = 0);
     ~SCTPGraphByteDialog();
 
 public slots:
@@ -45,7 +46,7 @@ private slots:
 
 private:
     Ui::SCTPGraphByteDialog *ui;
-    struct _sctp_assoc_info *selected_assoc;
+    guint16 selected_assoc_id;
     capture_file *cap_file_;
     int frame_num;
     int direction;
@@ -53,7 +54,7 @@ private:
     QVector<guint32> fb;
 
     void drawGraph();
-    void drawBytesGraph();
+    void drawBytesGraph(const _sctp_assoc_info *selected_assoc);
 };
 
 #endif // SCTP_GRAPH_DIALOG_H
diff --git a/ui/qt/sctp_graph_dialog.cpp b/ui/qt/sctp_graph_dialog.cpp
index 82bc5794b3..03201e6923 100644
--- a/ui/qt/sctp_graph_dialog.cpp
+++ b/ui/qt/sctp_graph_dialog.cpp
@@ -27,33 +27,34 @@
 #include "ui/qt/widgets/wireshark_file_dialog.h"
 #include "wireshark_application.h"
 
-SCTPGraphDialog::SCTPGraphDialog(QWidget *parent, sctp_assoc_info_t *assoc, capture_file *cf, int dir) :
+SCTPGraphDialog::SCTPGraphDialog(QWidget *parent, const sctp_assoc_info_t *assoc,
+        capture_file *cf, int dir) :
     QDialog(parent),
     ui(new Ui::SCTPGraphDialog),
-    selected_assoc(assoc),
     cap_file_(cf),
     frame_num(0),
     direction(dir),
     relative(false),
     type(1)
 {
+    Q_ASSERT(assoc);
+    selected_assoc_id = assoc->assoc_id;
+
     ui->setupUi(this);
-    if (!selected_assoc) {
-        selected_assoc = SCTPAssocAnalyseDialog::findAssocForPacket(cap_file_);
-    }
     Qt::WindowFlags flags = Qt::Window | Qt::WindowSystemMenuHint
             | Qt::WindowMinimizeButtonHint
             | Qt::WindowMaximizeButtonHint
             | Qt::WindowCloseButtonHint;
     this->setWindowFlags(flags);
-    this->setWindowTitle(QString(tr("SCTP TSNs and SACKs over Time: %1 Port1 %2 Port2 %3")).arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(selected_assoc->port1).arg(selected_assoc->port2));
-    if ((direction == 1 && selected_assoc->n_array_tsn1 == 0) || (direction == 2 && selected_assoc->n_array_tsn2 == 0)) {
+    this->setWindowTitle(QString(tr("SCTP TSNs and SACKs over Time: %1 Port1 %2 Port2 %3"))
+            .arg(gchar_free_to_qstring(cf_get_display_name(cap_file_))).arg(assoc->port1).arg(assoc->port2));
+    if ((direction == 1 && assoc->n_array_tsn1 == 0) || (direction == 2 && assoc->n_array_tsn2 == 0)) {
         QMessageBox msgBox;
         msgBox.setText(tr("No Data Chunks sent"));
         msgBox.exec();
         return;
     } else {
-        drawGraph();
+        drawGraph(assoc);
     }
 }
 
@@ -62,7 +63,7 @@ SCTPGraphDialog::~SCTPGraphDialog()
     delete ui;
 }
 
-void SCTPGraphDialog::drawNRSACKGraph()
+void SCTPGraphDialog::drawNRSACKGraph(const sctp_assoc_info_t* selected_assoc)
 {
     tsn_t *sack;
     GList *list=NULL, *tlist;
@@ -129,7 +130,7 @@ void SCTPGraphDialog::drawNRSACKGraph()
     }
 }
 
-void SCTPGraphDialog::drawSACKGraph()
+void SCTPGraphDialog::drawSACKGraph(const sctp_assoc_info_t* selected_assoc)
 {
     GList *listSACK = NULL, *tlist;
     guint16 gap_start=0, gap_end=0, nr, dup_nr;
@@ -257,7 +258,7 @@ void SCTPGraphDialog::drawSACKGraph()
     }
 }
 
-void SCTPGraphDialog::drawTSNGraph()
+void SCTPGraphDialog::drawTSNGraph(const sctp_assoc_info_t* selected_assoc)
 {
     GList *listTSN = NULL,*tlist;
     tsn_t *tsn;
@@ -313,8 +314,13 @@ void SCTPGraphDialog::drawTSNGraph()
     }
 }
 
-void SCTPGraphDialog::drawGraph()
+void SCTPGraphDialog::drawGraph(const sctp_assoc_info_t* selected_assoc)
 {
+    if (!selected_assoc) {
+        selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+        if (!selected_assoc) return;
+    }
+
     guint32 maxTSN, minTSN;
 
     if (direction == 1) {
@@ -342,18 +348,23 @@ void SCTPGraphDialog::drawGraph()
     fn.clear();
     typeStrings.clear();
     switch (type) {
-    case 1: drawSACKGraph();
-        drawNRSACKGraph();
+    case 1:
+        drawSACKGraph(selected_assoc);
+        drawNRSACKGraph(selected_assoc);
         break;
-    case 2: drawTSNGraph();
+    case 2:
+        drawTSNGraph(selected_assoc);
         break;
-    case 3: drawTSNGraph();
-        drawSACKGraph();
-        drawNRSACKGraph();
+    case 3:
+        drawTSNGraph(selected_assoc);
+        drawSACKGraph(selected_assoc);
+        drawNRSACKGraph(selected_assoc);
+        break;
+    default:
+        drawTSNGraph(selected_assoc);
+        drawSACKGraph(selected_assoc);
+        drawNRSACKGraph(selected_assoc);
         break;
-    default: drawTSNGraph();
-        drawSACKGraph();
-        drawNRSACKGraph();
     }
 
     // give the axes some labels:
@@ -394,6 +405,9 @@ void SCTPGraphDialog::on_pushButton_3_clicked()
 
 void SCTPGraphDialog::on_pushButton_4_clicked()
 {
+    const sctp_assoc_info_t* selected_assoc = SCTPAssocAnalyseDialog::findAssoc(this, selected_assoc_id);
+    if (!selected_assoc) return;
+
     ui->sctpPlot->xAxis->setRange(selected_assoc->min_secs, selected_assoc->max_secs+1);
     if (relative) {
         if (direction == 1) {
diff --git a/ui/qt/sctp_graph_dialog.h b/ui/qt/sctp_graph_dialog.h
index 8c9de7acc1..dc3e5b9227 100644
--- a/ui/qt/sctp_graph_dialog.h
+++ b/ui/qt/sctp_graph_dialog.h
@@ -77,7 +77,8 @@ class SCTPGraphDialog : public QDialog
     Q_OBJECT
 
 public:
-    explicit SCTPGraphDialog(QWidget *parent = 0, struct _sctp_assoc_info *assoc = NULL, capture_file *cf = NULL, int dir = 0);
+    explicit SCTPGraphDialog(QWidget *parent = 0, const _sctp_assoc_info *assoc = NULL,
+            capture_file *cf = NULL, int dir = 0);
     ~SCTPGraphDialog();
     static void save_graph(QDialog *dlg, QCustomPlot *plot);
 
@@ -101,7 +102,7 @@ private slots:
 
 private:
     Ui::SCTPGraphDialog *ui;
-    struct _sctp_assoc_info *selected_assoc;
+    guint16 selected_assoc_id;
     capture_file *cap_file_;
     int frame_num;
     int direction;
@@ -111,10 +112,10 @@ private:
     bool relative;
     int type;
 
-    void drawGraph();
-    void drawTSNGraph();
-    void drawSACKGraph();
-    void drawNRSACKGraph();
+    void drawGraph(const _sctp_assoc_info* selected_assoc = NULL);
+    void drawTSNGraph(const _sctp_assoc_info* selected_assoc);
+    void drawSACKGraph(const _sctp_assoc_info* selected_assoc);
+    void drawNRSACKGraph(const _sctp_assoc_info* selected_assoc);
 };
 
 #endif // SCTP_GRAPH_DIALOG_H
diff --git a/ui/tap-sctp-analysis.c b/ui/tap-sctp-analysis.c
index 8400e7ec51..3747f4df3a 100644
--- a/ui/tap-sctp-analysis.c
+++ b/ui/tap-sctp-analysis.c
@@ -1258,6 +1258,12 @@ sctp_stat_get_info(void)
     return &sctp_tapinfo_struct;
 }
 
+const sctp_assoc_info_t *
+get_sctp_assoc_info(guint16 assoc_id)
+{
+    sctp_tmp_info_t needle = { .assoc_id = assoc_id };
+    return find_assoc(&needle);
+}
 
 void
 register_tap_listener_sctp_stat(void)
diff --git a/ui/tap-sctp-analysis.h b/ui/tap-sctp-analysis.h
index 40b7f50d59..10f4afd81b 100644
--- a/ui/tap-sctp-analysis.h
+++ b/ui/tap-sctp-analysis.h
@@ -295,7 +295,7 @@ void sctp_stat_scan(void);
 
 void remove_tap_listener_sctp_stat(void);
 
-
+const sctp_assoc_info_t* get_sctp_assoc_info(guint16 assoc_id);
 const sctp_assoc_info_t* get_selected_assoc(void);
 
 #ifdef __cplusplus