linux-kernel - [PATCH -tip] KVM: SVM: nested: Initialize on-stack pointers in svm_set_nested

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Message-Id: <20200914115129.10352-1-joro@8bytes.org>
Date:   Mon, 14 Sep 2020 13:51:29 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Borislav Petkov <bp@...en8.de>, Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>, x86@...nel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Joerg Roedel <jroedel@...e.de>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: [PATCH -tip] KVM: SVM: nested: Initialize on-stack pointers in svm_set_nested_state()

From: Joerg Roedel <jroedel@...e.de>

The save and ctl pointers need to be initialized to NULL because there
is a way through the function in which there is no memory allocated
for the pointers but where they are freed in the end.

This involves the 'goto out_set_gif' before the memory for the
pointers is allocated.

Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Fixes: 6ccbd29ade0d ("KVM: SVM: nested: Don't allocate VMCB structures on stack")
Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 arch/x86/kvm/svm/nested.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 598a769f1961..72a3d6f87107 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1062,8 +1062,8 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 	struct vmcb *hsave = svm->nested.hsave;
 	struct vmcb __user *user_vmcb = (struct vmcb __user *)
 		&user_kvm_nested_state->data.svm[0];
-	struct vmcb_control_area *ctl;
-	struct vmcb_save_area *save;
+	struct vmcb_control_area *ctl = NULL;
+	struct vmcb_save_area *save = NULL;
 	int ret;
 	u32 cr0;
 
-- 
2.28.0