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Fix a crash which can occur if a user hits "Capture:Options" immediately followed by "Capture:Start" 

Fixes Bug #4645: https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=4645

Essentially: The "Capture Start" code "interrupted" the "Capture Options" code and attempted
 to use not yet initialized "Capture Options" state.

svn path=/trunk/; revision=35633
This commit is contained in:
Bill Meier 2011-01-23 20:59:12 +00:00
parent f7544b339e
commit becab16f36
1 changed files with 57 additions and 9 deletions
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66
gtk/capture_dlg.c
View File

@ -159,11 +159,15 @@
/*
* Keep a static pointer to the current "Capture Options" window, if
* any, so that if somebody tries to do "Capture:Start" while there's
* any, so that if somebody tries to do "Capture:Options" while there's
* already a "Capture Options" window up, we just pop up the existing
* one, rather than creating a new one.
* Also: Capture:Start obtains info from the "Capture Options" window
* if it exists and if its creation is complete.
*/
static GtkWidget *cap_open_w;
static GtkWidget *cap_open_w = NULL;
static gboolean cap_open_complete; /* valid only if cap_open_w != NULL */
static GHashTable *cap_settings_history=NULL;
#ifdef HAVE_PCAP_REMOTE
@ -368,9 +372,9 @@ set_if_capabilities(gboolean monitor_mode_changed)
if (iftype >= CAPTURE_IFREMOTE)
if_list = (GList *) g_object_get_data(G_OBJECT(cap_open_w), E_CAP_IF_LIST_KEY);
else
if_list = capture_interface_list(&err, NULL);
if_list = capture_interface_list(&err, NULL); /* Warning: see capture_prep_cb() */
#else
if_list = capture_interface_list(&err, NULL);
if_list = capture_interface_list(&err, NULL); /* Warning: see capture_prep_cb() */
#endif
if (if_list != NULL) {
/*
@ -909,7 +913,7 @@ update_interface_list()
&err, &err_str);
g_object_set_data(G_OBJECT(cap_open_w), E_CAP_IF_LIST_KEY, if_list);
} else {
if_list = capture_interface_list(&err, &err_str);
if_list = capture_interface_list(&err, &err_str); /* Warning: see capture_prep_cb() */
g_object_set_data(G_OBJECT(cap_open_w), E_CAP_IF_LIST_KEY, NULL);
}
@ -1557,6 +1561,38 @@ capture_filter_compile_cb(GtkWidget *w _U_, gpointer user_data _U_)
#endif
/* show capture prepare (options) dialog */
/* XXX: Warning:
Note that capture_interface_list() is called directly (or indirectly) during the
creation of (and changes to) the capture options dialog window.
Also note that capture_interface_list() indirectly runs the gtk main loop temporarily
to process queued events (which may include button-presses, key-presses, etc).
(This is done while awaiting a response from dumpcap which is invoked to obtain
the capture interface list).
This means other Wireshark callbacks can be invoked while the capture options window
is being created or updated (in effect an "interrupt" can occur).
Needless to say, "race conditions" may occur in "interrupt" code which depends upon the exact
state of the capture options dialog window and which may be invoked during the
creation of (or changes to) the capture options dialog window.
For example: if a user hits "Capture:Options" and then immediately hits "Capture:Start",
capture_start_cb() may be invoked before capture_prep_cb() has been completed (i.e., during
a call to capture_interface_list() in the code which creates the capture options window).
capture_start_cb() depends upon certain properties of the capture options window having been
initialized and thus fails if the properties have not (yet) been initialized.
An interlock has been added to handle this particular situation;
Ideally a more general solution should be implemented since it's probably difficult
(if not nearly impossible) to identify all the possible "race conditions".
? Prevent the temporary running of the gtk main loop in cases wherein dumpcap is invoked for a
simple request/reply ? (e.g., capture_interface_list()) ??
? Other ??
*/
void
capture_prep_cb(GtkWidget *w _U_, gpointer d _U_)
{
@ -1642,11 +1678,11 @@ capture_prep_cb(GtkWidget *w _U_, gpointer d _U_)
/* use user-defined title if preference is set */
cap_title = create_user_window_title("Wireshark: Capture Options");
cap_open_complete = FALSE;
cap_open_w = dlg_window_new(cap_title);
g_free(cap_title);
tooltips = gtk_tooltips_new();
#ifdef HAVE_PCAP_REMOTE
if (global_capture_opts.src_type == CAPTURE_IFREMOTE) {
if_list = get_remote_interface_list(global_capture_opts.remote_host,
@ -1665,18 +1701,18 @@ capture_prep_cb(GtkWidget *w _U_, gpointer d _U_)
g_free (global_capture_opts.iface_descr);
global_capture_opts.iface_descr = NULL;
}
if_list = capture_interface_list(&err, &err_str);
if_list = capture_interface_list(&err, &err_str); /* Warning: see capture_prep_cb() */
global_capture_opts.src_type = CAPTURE_IFLOCAL;
g_object_set_data(G_OBJECT(cap_open_w), E_CAP_IF_LIST_KEY, NULL);
} else {
g_object_set_data(G_OBJECT(cap_open_w), E_CAP_IF_LIST_KEY, if_list);
}
} else {
if_list = capture_interface_list(&err, &err_str);
if_list = capture_interface_list(&err, &err_str); /* Warning: see capture_prep_cb() */
g_object_set_data(G_OBJECT(cap_open_w), E_CAP_IF_LIST_KEY, NULL);
}
#else
if_list = capture_interface_list(&err, &err_str);
if_list = capture_interface_list(&err, &err_str); /* Warning: see capture_prep_cb() */
#endif
if (if_list == NULL && err == CANT_GET_INTERFACE_LIST) {
simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", err_str);
@ -1746,6 +1782,9 @@ capture_prep_cb(GtkWidget *w _U_, gpointer d _U_)
make the one from the preferences file the default */
if_device = g_strdup(prefs.capture_device);
global_capture_opts.iface = g_strdup(get_if_name(if_device));
/* Warning: see capture_prep_cb() */
/* XXX: Could the following code be changed to use the if_list obtained above instead */
/* of maybe calling capture_interface_list() again ? */
global_capture_opts.iface_descr = get_interface_descriptive_name(global_capture_opts.iface);
g_free(if_device);
}
@ -2437,6 +2476,8 @@ capture_prep_cb(GtkWidget *w _U_, gpointer d _U_)
gtk_widget_show_all(cap_open_w);
window_present(cap_open_w);
cap_open_complete = TRUE; /* "Capture:Start" is now OK */
}
/* everythings prepared, now it's really time to start the capture */
@ -2531,6 +2572,13 @@ capture_start_cb(GtkWidget *w _U_, gpointer d _U_)
*/
gboolean success;
/* Determine if "capture start" while building of the "capture options" window */
/* is in progress. If so, ignore the "capture start. */
/* XXX: Would it be better/cleaner for the "capture options" window code to */
/* disable the capture start button temporarily ? */
if (cap_open_complete == FALSE) {
return; /* Building options window: ignore "capture start" */
}
success = capture_dlg_prep(cap_open_w);
window_destroy(GTK_WIDGET(cap_open_w));
if (!success)