linux-kernel - [PATCH v2] x86: kvm: fix information leak to userland

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Date:	Sat, 30 Oct 2010 18:11:11 +0400
From:	Vasiliy Kulikov <segooon@...il.com>
To:	kernel-janitors@...r.kernel.org
Cc:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] x86: kvm: fix information leak to userland

Structure kvm_ppc_pvinfo is copied to userland with pad field
unitialized.  Structure kvm_clock_data is copied to userland with
flags and pad fields unitialized.  It leads to leaking of contents
of kernel stack memory.

Signed-off-by: Vasiliy Kulikov <segooon@...il.com>
---
 I cannot compile this driver, so it is not tested at all.

 As it is not compilable, I've missed and typed wrong var name in v1, sorry.

 arch/x86/kvm/x86.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b0818f6..261f3d0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2896,6 +2896,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	case KVM_GET_DEBUGREGS: {
 		struct kvm_debugregs dbgregs;
 
+		memset(&dbgregs, 0, sizeof(dbgregs));
 		kvm_vcpu_ioctl_x86_get_debugregs(vcpu, &dbgregs);
 
 		r = -EFAULT;
@@ -3481,11 +3482,11 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		struct kvm_clock_data user_ns;
 		u64 now_ns;
 
+		memset(&user_ns, 0, sizeof(user_ns));
 		local_irq_disable();
 		now_ns = get_kernel_ns();
 		user_ns.clock = kvm->arch.kvmclock_offset + now_ns;
 		local_irq_enable();
-		user_ns.flags = 0;
 
 		r = -EFAULT;
 		if (copy_to_user(argp, &user_ns, sizeof(user_ns)))
-- 
1.7.0.4

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