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* [PATCH for-4.5] arm/kvm: fix ioctl error handling
@ 2016-02-28 15:32 Michael S. Tsirkin
  2016-02-29  8:29 ` Christoffer Dall
  0 siblings, 1 reply; 2+ messages in thread
From: Michael S. Tsirkin @ 2016-02-28 15:32 UTC (permalink / raw)
  To: linux-arm-kernel

Calling return copy_to_user(...) in an ioctl will not
do the right thing if there's a pagefault:
copy_to_user returns the number of bytes not copied
in this case.

Fix up kvm to do
	return copy_to_user(...)) ?  -EFAULT : 0;

everywhere.

Cc: stable at vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Compiled only.

 arch/arm/kvm/guest.c   | 2 +-
 arch/arm64/kvm/guest.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
index 5fa69d7..99361f1 100644
--- a/arch/arm/kvm/guest.c
+++ b/arch/arm/kvm/guest.c
@@ -161,7 +161,7 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	u64 val;
 
 	val = kvm_arm_timer_get_reg(vcpu, reg->id);
-	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id));
+	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0;
 }
 
 static unsigned long num_core_regs(void)
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index fcb7788..9e54ad7 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -194,7 +194,7 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	u64 val;
 
 	val = kvm_arm_timer_get_reg(vcpu, reg->id);
-	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id));
+	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0;
 }
 
 /**
-- 
MST

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [PATCH for-4.5] arm/kvm: fix ioctl error handling
  2016-02-28 15:32 [PATCH for-4.5] arm/kvm: fix ioctl error handling Michael S. Tsirkin
@ 2016-02-29  8:29 ` Christoffer Dall
  0 siblings, 0 replies; 2+ messages in thread
From: Christoffer Dall @ 2016-02-29  8:29 UTC (permalink / raw)
  To: linux-arm-kernel

On Sun, Feb 28, 2016 at 05:32:07PM +0200, Michael S. Tsirkin wrote:
> Calling return copy_to_user(...) in an ioctl will not
> do the right thing if there's a pagefault:
> copy_to_user returns the number of bytes not copied
> in this case.
> 
> Fix up kvm to do
> 	return copy_to_user(...)) ?  -EFAULT : 0;
> 
> everywhere.
> 
> Cc: stable at vger.kernel.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Acked-by: Christoffer Dall <christoffer.dall@linaro.org>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2016-02-28 15:32 [PATCH for-4.5] arm/kvm: fix ioctl error handling Michael S. Tsirkin
2016-02-29  8:29 ` Christoffer Dall

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