Re: [PATCH v2] consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c
From: Gen Zhang
Date: Thu May 23 2019 - 22:17:51 EST
On Thu, May 23, 2019 at 09:54:18AM -0700, Kees Cook wrote:
> On Thu, May 23, 2019 at 08:34:52AM +0800, Gen Zhang wrote:
> > In function con_insert_unipair(), when allocation for p2 and p1[n]
> > fails, ENOMEM is returned, but previously allocated p1 is not freed,
> > remains as leaking memory. Thus we should free p1 as well when this
> > allocation fails.
> >
> > Signed-off-by: Gen Zhang <blackgod016574@xxxxxxxxx>
>
> As far as I can see this is correct, as it's just restoring the prior
> state before the p1 allocation.
>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
>
Thanks for your review, Kees!
Thanks
Gen
> > ---
> > diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> > index b28aa0d..79fcc96 100644
> > --- a/drivers/tty/vt/consolemap.c
> > +++ b/drivers/tty/vt/consolemap.c
> > @@ -489,7 +489,11 @@ con_insert_unipair(struct uni_pagedir *p, u_short unicode, u_short fontpos)
> > p2 = p1[n = (unicode >> 6) & 0x1f];
> > if (!p2) {
> > p2 = p1[n] = kmalloc_array(64, sizeof(u16), GFP_KERNEL);
> > - if (!p2) return -ENOMEM;
> > + if (!p2) {
> > + kfree(p1);
> > + p->uni_pgdir[n] = NULL;
> > + return -ENOMEM;
> > + }
> > memset(p2, 0xff, 64*sizeof(u16)); /* No glyphs for the characters (yet) */
> > }
> >
> > ---
>
> --
> Kees Cook