linux-kernel - Re: [PATCH v3] KVM: remove buggy vcpu id check on vcpu creation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 20 Apr 2016 19:53:29 +0200
From:	Greg Kurz <gkurz@...ux.vnet.ibm.com>
To:	Radim Krčmář <rkrcmar@...hat.com>
Cc:	James Hogan <james.hogan@...tec.com>,
	Paolo Bonzini <pbonzini@...hat.com>, mingo@...hat.com,
	linux-mips@...ux-mips.org, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, qemu-ppc@...gnu.org,
	Cornelia Huck <cornelia.huck@...ibm.com>,
	Paul Mackerras <paulus@...ba.org>,
	David Gibson <david@...son.dropbear.id.au>
Subject: Re: [PATCH v3] KVM: remove buggy vcpu id check on vcpu creation

On Wed, 20 Apr 2016 19:27:06 +0200
Radim Krčmář <rkrcmar@...hat.com> wrote:

> 2016-04-20 18:09+0100, James Hogan:
> > On Wed, Apr 20, 2016 at 07:02:10PM +0200, Radim Krčmář wrote:  
> >> 2016-04-20 17:44+0200, Greg Kurz:  
> >> > diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> >> > index 70ef1a43c114..0278ea146db5 100644
> >> > --- a/arch/mips/kvm/mips.c
> >> > +++ b/arch/mips/kvm/mips.c
> >> > @@ -248,9 +248,14 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
> >> >  	int err, size, offset;
> >> >  	void *gebase;
> >> >  	int i;
> >> > +	struct kvm_vcpu *vcpu;
> >> >  
> >> > -	struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL);
> >> > +	if (id >= KVM_MAX_VCPUS) {
> >> > +		err = -EINVAL;
> >> > +		goto out;  
> >> 
> >> 'vcpu' looks undefined at this point, so kfree in 'out:' may bug.  
> > 
> > Thats out_free_cpu I think?  
> 
> My bad, it is.  Thank you!
> 

I kept the goto based construct because it was done this way for kzalloc().
but I agree that 'return ERR_PTR(-EINVAL)' may look more explicit.

Worth a v4 ?

Cheers.

--
Greg