[PATCH] SVM: nSVM: fix resource leak on error path

[PATCH] SVM: nSVM: fix resource leak on error path

[Alex Dewar]

In svm_set_nested_state(), if nested_svm_vmrun_msrpm() returns false,
then variables save and ctl will leak. Fix this.

Fixes: 772b81bb2f9b ("SVM: nSVM: setup nested msr permission bitmap on nested state load")
Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
---
 arch/x86/kvm/svm/nested.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 598a769f1961..85f572cbabe4 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1148,7 +1148,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 	nested_prepare_vmcb_control(svm);
 
 	if (!nested_svm_vmrun_msrpm(svm))
-		return -EINVAL;
+		goto out_free;	/* ret == -EINVAL */
 
 out_set_gif:
 	svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET));
-- 
2.28.0

Re: [PATCH] SVM: nSVM: fix resource leak on error path

[Maxim Levitsky]

On Mon, 2020-09-14 at 20:45 +0100, Alex Dewar wrote:
> In svm_set_nested_state(), if nested_svm_vmrun_msrpm() returns false,
> then variables save and ctl will leak. Fix this.
> 
> Fixes: 772b81bb2f9b ("SVM: nSVM: setup nested msr permission bitmap on nested state load")
> Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
> ---
>  arch/x86/kvm/svm/nested.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index 598a769f1961..85f572cbabe4 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -1148,7 +1148,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
>  	nested_prepare_vmcb_control(svm);
>  
>  	if (!nested_svm_vmrun_msrpm(svm))
> -		return -EINVAL;
> +		goto out_free;	/* ret == -EINVAL */
>  
>  out_set_gif:
>  	svm_set_gif(svm, !!(kvm_state->flags & KVM_STATE_NESTED_GIF_SET));

I think that this patch is based on unmerged patch, since I don't see
any memory allocation in nested_svm_vmrun_msrpm, nor out_free label.
in nether kvm/master, kvm/queue nor in upstream/master

If I recall correctly that would be something about allocating ctrl/save
dynamically rather than on stack.

Best regards,
	Maxim Levitsky

Re: [PATCH] SVM: nSVM: fix resource leak on error path

[Borislav Petkov]

On Tue, Sep 15, 2020 at 12:07:25PM +0300, Maxim Levitsky wrote:
> I think that this patch is based on unmerged patch, since I don't see
> any memory allocation in nested_svm_vmrun_msrpm, nor out_free label.
> in nether kvm/master, kvm/queue nor in upstream/master

Paolo and I need to figure out first how to share the SEV-ES enablement
work and the other patches touching that file and then pile more fixes
ontop.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] SVM: nSVM: fix resource leak on error path

[Alex Dewar]

On Tue, Sep 15, 2020 at 11:15:02AM +0200, Borislav Petkov wrote:
> On Tue, Sep 15, 2020 at 12:07:25PM +0300, Maxim Levitsky wrote:
> > I think that this patch is based on unmerged patch, since I don't see
> > any memory allocation in nested_svm_vmrun_msrpm, nor out_free label.
> > in nether kvm/master, kvm/queue nor in upstream/master
> 
> Paolo and I need to figure out first how to share the SEV-ES enablement
> work and the other patches touching that file and then pile more fixes
> ontop.

Sorry for the noise! I didn't realise this was a work in progress --
Coverity picked it up.

> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette