Subject: linux-4.4-rc8/arch/arm64/kernel/module.c:78: 32/64 bit problem ?

From: [email-masked] (Will Deacon)
Date: Mon, 4 Jan 2016 15:30:28 +0000

On Mon, Jan 04, 2016 at 03:28:41PM +0000, Will Deacon wrote:
> On Mon, Jan 04, 2016 at 04:24:49PM +0100, Ard Biesheuvel wrote:
> > diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
> > index f4bc779e62e8..fd1f4e678655 100644
> > --- a/arch/arm64/kernel/module.c
> > +++ b/arch/arm64/kernel/module.c
> > @@ -75,14 +75,17 @@ static u64 do_reloc(enum aarch64_reloc_op
> > reloc_op, void *place, u64 val)
> > 
> >  static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len)
> >  {
> > -       u64 imm_mask = (1 << len) - 1;
> >         s64 sval = do_reloc(op, place, val);
> > 
> >         switch (len) {
> >         case 16:
> > +               if (sval < S16_MIN || sval > U16_MAX)
> > +                       return -ERANGE;
> >                 *(s16 *)place = sval;
> 
> Doesn't this break ABS relocs, which are allowed to overflow?

Gah, that only applies to the 64-bit relocs. Sorry for the noise.

Will