[virt-tools-list] [PATCH v2] remote-viewer: fix free on dangling pointer
Victor Toso
victortoso at redhat.com
Tue Oct 1 10:09:04 UTC 2019
Hi,
On Mon, Sep 30, 2019 at 11:01:42AM -0300, Eduardo Lima (Etrunko) wrote:
> On 9/30/19 5:08 AM, Victor Toso wrote:
> > From: Victor Toso <me at victortoso.com>
> >
> > On remote_viewer_session_connected() we are passing a dup of URI of
> > connection and freeing it afterwards. Problem is, we don't disconnect
> > from listening "session-connected" and on an eventual second emission
> > of this signal, remote-viewer crashes as seen in the backtrace below.
> >
> > This can happen over switch-host migration message from
> > SpiceMainChannel.
> >
> > To fix the issue, use VirtViewerApp URI information instead of passing
> > a dup char*. The other changes in this patch were warnings of unused
> > variables.
> >
> > Found it while improving migrate.py from spice/tests (server):
> > | Invalid free() / delete / delete[] / realloc()
> > | at 0x4839A0C: free (vg_replace_malloc.c:540)
> > | by 0x56EBD8C: g_free (in /usr/lib64/libglib-2.0.so.0.6000.6)
> > | by 0x11DED0: remote_viewer_session_connected (remote-viewer.c:658)
> > | by 0x564D741: g_closure_invoke (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x56614F3: ??? (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566A34D: g_signal_emit_valist (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566AF68: g_signal_emit_by_name (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x135E5D: virt_viewer_session_spice_main_channel_event (virt-viewer-session-spice.c:699)
> > | by 0x564D741: g_closure_invoke (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x56614F3: ??? (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566A34D: g_signal_emit_valist (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x53149E3: emit_main_context (gio-coroutine.c:198)
> > | Address 0x18f1ecc0 is 0 bytes inside a block of size 23 free'd
> > | at 0x4839A0C: free (vg_replace_malloc.c:540)
> > | by 0x56EBD8C: g_free (in /usr/lib64/libglib-2.0.so.0.6000.6)
> > | by 0x11DED0: remote_viewer_session_connected (remote-viewer.c:658)
> > | by 0x564D741: g_closure_invoke (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x56614F3: ??? (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566A34D: g_signal_emit_valist (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566AF68: g_signal_emit_by_name (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x135E5D: virt_viewer_session_spice_main_channel_event (virt-viewer-session-spice.c:699)
> > | by 0x564D741: g_closure_invoke (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x56614F3: ??? (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566A34D: g_signal_emit_valist (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x53149E3: emit_main_context (gio-coroutine.c:198)
> > | Block was alloc'd at
> > | at 0x483880B: malloc (vg_replace_malloc.c:309)
> > | by 0x56EBC98: g_malloc (in /usr/lib64/libglib-2.0.so.0.6000.6)
> > | by 0x5705C43: g_strdup (in /usr/lib64/libglib-2.0.so.0.6000.6)
> > | by 0x11EB80: remote_viewer_initial_connect (remote-viewer.c:696)
> > | by 0x11EB80: remote_viewer_start (remote-viewer.c:790)
> > | by 0x1250D3: virt_viewer_app_start (virt-viewer-app.c:1727)
> > | by 0x127108: virt_viewer_app_on_application_startup (virt-viewer-app.c:1870)
> > | by 0x564D741: g_closure_invoke (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x5661638: ??? (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566A34D: g_signal_emit_valist (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x566A972: g_signal_emit (in /usr/lib64/libgobject-2.0.so.0.6000.6)
> > | by 0x553ECA1: g_application_register (in /usr/lib64/libgio-2.0.so.0.6000.6)
> > | by 0x553F41D: g_application_run (in /usr/lib64/libgio-2.0.so.0.6000.6)
> >
> > Signed-off-by: Victor Toso <victortoso at redhat.com>
> > ---
> > src/remote-viewer.c | 18 ++++++++++--------
> > 1 file changed, 10 insertions(+), 8 deletions(-)
> >
> > diff --git a/src/remote-viewer.c b/src/remote-viewer.c
> > index 8938ef9..7cad231 100644
> > --- a/src/remote-viewer.c
> > +++ b/src/remote-viewer.c
> > @@ -396,7 +396,7 @@ virt_viewer_app_set_ovirt_foreign_menu(VirtViewerApp *app,
> > }
> > static gboolean
> > -create_ovirt_session(VirtViewerApp *app, const char *uri, GError **err)
> > +create_ovirt_session(VirtViewerApp *app, GError **err)
> > {
> > OvirtProxy *proxy = NULL;
> > OvirtApi *api = NULL;
> > @@ -421,9 +421,11 @@ create_ovirt_session(VirtViewerApp *app, const char *uri, GError **err)
> > gchar *ticket = NULL;
> > gchar *host_subject = NULL;
> > gchar *guid = NULL;
> > + gchar *uri = NULL;
> > g_return_val_if_fail(VIRT_VIEWER_IS_APP(app), FALSE);
> > + g_object_get(app, "guri", &uri, NULL);
> > if (!parse_ovirt_uri(uri, &rest_uri, &vm_name, &username)) {
> > g_set_error_literal(&error, VIRT_VIEWER_ERROR, VIRT_VIEWER_ERROR_FAILED,
> > _("failed to parse ovirt uri"));
> > @@ -561,6 +563,7 @@ create_ovirt_session(VirtViewerApp *app, const char *uri, GError **err)
> > success = TRUE;
> > error:
> > + g_free(uri);
> > g_free(username);
> > g_free(rest_uri);
> > g_free(vm_name);
> > @@ -645,17 +648,16 @@ remote_viewer_recent_add(gchar *uri, const gchar *mime_type)
> > static void
> > remote_viewer_session_connected(VirtViewerSession *session,
> > - gchar *guri)
> > + VirtViewerApp *app)
> > {
> > gchar *uri = virt_viewer_session_get_uri(session);
> > const gchar *mime = virt_viewer_session_mime_type(session);
> > if (uri == NULL)
> > - uri = g_strdup(guri);
> > + g_object_get(app, "guri", &uri, NULL);
> > remote_viewer_recent_add(uri, mime);
> > g_free(uri);
> > - g_free(guri);
> > }
>
> Patch builds now, but I started getting some warning when connecting to
> ovirt:// uri.
>
> (remote-viewer:16940): virt-viewer-CRITICAL **: 11:00:14.560:
> remote_viewer_recent_add: assertion 'uri != NULL' failed
Right, this refactor is not straightforward on ovirt codepath.
Thanks for testing it properly. I've sent a v3 without touching
ovirt code now.
Cheers,
>
>
> > static gchar *
> > @@ -675,14 +677,14 @@ read_all_stdin(gsize *len, GError **err)
> > }
> > static gboolean
> > -remote_viewer_initial_connect(RemoteViewer *self, const gchar *type, const gchar *guri,
> > +remote_viewer_initial_connect(RemoteViewer *self, const gchar *type,
> > VirtViewerFile *vvfile, GError **error)
> > {
> > VirtViewerApp *app = VIRT_VIEWER_APP(self);
> > #ifdef HAVE_OVIRT
> > if (g_strcmp0(type, "ovirt") == 0) {
> > - if (!create_ovirt_session(app, guri, error)) {
> > + if (!create_ovirt_session(app, error)) {
> > g_prefix_error(error, _("Couldn't open oVirt session: "));
> > return FALSE;
> > }
> > @@ -694,7 +696,7 @@ remote_viewer_initial_connect(RemoteViewer *self, const gchar *type, const gchar
> > }
> > g_signal_connect(virt_viewer_app_get_session(app), "session-connected",
> > - G_CALLBACK(remote_viewer_session_connected), g_strdup(guri));
> > + G_CALLBACK(remote_viewer_session_connected), app);
> > virt_viewer_session_set_file(virt_viewer_app_get_session(app), vvfile);
> > #ifdef HAVE_OVIRT
> > @@ -787,7 +789,7 @@ retry_dialog:
> > _("Cannot determine the connection type from URI"));
> > goto cleanup;
> > }
> > - if (!remote_viewer_initial_connect(self, type, guri, vvfile, &error))
> > + if (!remote_viewer_initial_connect(self, type, vvfile, &error))
> > goto cleanup;
> > }
> >
>
>
> --
> Eduardo de Barros Lima (Etrunko)
> Software Engineer - Red Hat
> etrunko at redhat.com
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