Qt: Fixed column issues when changing profile.

Always initialize prefs.col_list in pre_init_prefs.
When switching to a profile without a saved 'preferences' file we
have to initialize prefs.col_list to default values to avoid reusing
settings from the profile we leave.
This was introduced in 5012cf84e6d84a448171dac64c14d9c83e3d4ae6

Emit columnsChanged() before preferencesChanged().
This because columnsChanged() rebuilds cap_file_->cinfo which is used
in preferencesChanged() to align columns (and possible other actions).
Doing this in the wrong order will give an inconsistency and a
heap-buffer-overflow if having different number of columns.

Bug: 11493
Change-Id: I5792dfc0ede11b9457b96f092af8da00453787b1
Reviewed-on: https://code.wireshark.org/review/11971
Reviewed-by: Stig Bjørlykke <stig@bjorlykke.org>

1 files changed, 14 insertions, 13 deletions

diff --git a/epan/prefs.c b/epan/prefs.c
index 36cd4ebd7a..a1b4072b0e 100644
--- a/epan/prefs.c
+++ b/epan/prefs.c
@@ -3036,20 +3036,21 @@ pre_init_prefs(void)
 
     prefs.gui_qt_packet_list_separator = FALSE;
 
-    if (!prefs.col_list) {
-        /* First time through */
-        for (i = 0; i < DEF_NUM_COLS; i++) {
-            cfmt = g_new(fmt_data,1);
-            cfmt->title = g_strdup(col_fmt[i * 2]);
-            parse_column_format(cfmt, col_fmt[(i * 2) + 1]);
-            cfmt->visible = TRUE;
-            cfmt->resolved = TRUE;
-            cfmt->custom_field = NULL;
-            cfmt->custom_occurrence = 0;
-            prefs.col_list = g_list_append(prefs.col_list, cfmt);
-        }
-        prefs.num_cols  = DEF_NUM_COLS;
+    if (prefs.col_list) {
+        free_col_info(prefs.col_list);
+        prefs.col_list = NULL;
+    }
+    for (i = 0; i < DEF_NUM_COLS; i++) {
+        cfmt = g_new(fmt_data,1);
+        cfmt->title = g_strdup(col_fmt[i * 2]);
+        parse_column_format(cfmt, col_fmt[(i * 2) + 1]);
+        cfmt->visible = TRUE;
+        cfmt->resolved = TRUE;
+        cfmt->custom_field = NULL;
+        cfmt->custom_occurrence = 0;
+        prefs.col_list = g_list_append(prefs.col_list, cfmt);
     }
+    prefs.num_cols  = DEF_NUM_COLS;
 
 /* set the default values for the capture dialog box */
     prefs.capture_prom_mode             = TRUE;