linux-kernel - [PATCH][next] KVM: SVM: nested: fix free of uninitialized pointers save and ctl

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Message-Id: <20200911110730.24238-1-colin.king@canonical.com>
Date:   Fri, 11 Sep 2020 12:07:30 +0100
From:   Colin King <colin.king@...onical.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE),
        "H . Peter Anvin" <hpa@...or.com>, kvm@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] KVM: SVM: nested: fix free of uninitialized pointers save and ctl

From: Colin Ian King <colin.king@...onical.com>

Currently the error exit path to outt_set_gif will kfree on uninitialized
pointers save and ctl.  Fix this by ensuring these pointers are
inintialized to NULL to avoid garbage pointer freeing.

Addresses-Coverity: ("Uninitialized pointer read")
Fixes: 6ccbd29ade0d ("KVM: SVM: nested: Don't allocate VMCB structures on stack")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 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 28036629abf8..2b15f49f9e5a 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1060,8 +1060,8 @@ 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;
 
-- 
2.27.0