| Date | Wed, 16 Jun 2021 17:31:38 +0200 | From | Borislav Petkov <> | Subject | Re: [patch V2 12/52] x86/fpu: Fail ptrace() requests that try to set invalid MXCSR values |
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On Mon, Jun 14, 2021 at 05:44:20PM +0200, Thomas Gleixner wrote: > From: Andy Lutomirski <luto@kernel.org> > > We're not doing anyone any favors by accepting and silently changing an > invalid MXCSR value supplied via ptrace(). Instead, return -EINVAL on > invalid input. > > If this breaks something, we can revert it.
Please use passive voice in your commit message: no "we" or "I", etc,
> Signed-off-by: Andy Lutomirski <luto@kernel.org> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > V2: New patch. Picked up from Andy. > --- > arch/x86/kernel/fpu/regset.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > --- > --- a/arch/x86/kernel/fpu/regset.c > +++ b/arch/x86/kernel/fpu/regset.c > @@ -65,8 +65,9 @@ int xfpregs_set(struct task_struct *targ > if (ret) > return ret; > > - /* Mask invalid MXCSR bits (for historical reasons). */ > - newstate.mxcsr &= mxcsr_feature_mask; > + /* Do not allow an invalid MXCSR value. */ > + if (newstate.mxcsr & ~mxcsr_feature_mask) > + ret = -EINVAL; > > fpu__prepare_write(fpu);
With that addressed:
Reviewed-by: Borislav Petkov <bp@suse.de>
Thx.
-- Regards/Gruss, Boris.
SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
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