On Sun, Jun 09, 2019 at 12:01:38AM +0800, Gen Zhang wrote:
> On Tue, May 28, 2019 at 08:45:29AM +0800, Gen Zhang wrote:
> > In function con_init(), the pointer variable vc_cons[currcons].d, vc and
> > vc->vc_screenbuf is allocated by kzalloc(). And they are used in the
> > following codes. However, kzalloc() returns NULL when fails, and null
> > pointer dereference may happen. And it will cause the kernel to crash.
> > Therefore, we should check the return value and handle the error.
> >
> > Further, since the allcoation is in a loop, we should free all the
> > allocated memory in a loop.
> >
> > Signed-off-by: Gen Zhang <blackgod016...@gmail.com>
> > Reviewed-by: Nicolas Pitre <n...@fluxnic.net>
> > ---
> > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
> > index fdd12f8..d50f68f 100644
> > --- a/drivers/tty/vt/vt.c
> > +++ b/drivers/tty/vt/vt.c
> > @@ -3350,10 +3350,14 @@ static int __init con_init(void)
> >
> > for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
> > vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data),
> > GFP_NOWAIT);
> > + if (!vc)
> > + goto fail1;
> > INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
> > tty_port_init(&vc->port);
> > visual_init(vc, currcons, 1);
> > vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
> > + if (!vc->vc_screenbuf)
> > + goto fail2;
> > vc_init(vc, vc->vc_rows, vc->vc_cols,
> > currcons || !vc->vc_sw->con_save_screen);
> > }
> > @@ -3375,6 +3379,16 @@ static int __init con_init(void)
> > register_console(&vt_console_driver);
> > #endif
> > return 0;
> > +fail1:
> > + while (currcons > 0) {
> > + currcons--;
> > + kfree(vc_cons[currcons].d->vc_screenbuf);
> > +fail2:
> > + kfree(vc_cons[currcons].d);
> > + vc_cons[currcons].d = NULL;
> > + }
> > + console_unlock();
> > + return -ENOMEM;
> > }
> > console_initcall(con_init);
> >
> > ---
> Can anyone look into this patch? It's already reviewed by Nicolas Pitre
> <n...@fluxnic.net>.
It's in my queue. But note, given the previous history of your patches,
it's really low on my piority list at the moment :(
greg k-h
