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From: Nicholas Piggin <npiggin@gmail.com>
To: kvm-ppc@vger.kernel.org
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
	linuxppc-dev@lists.ozlabs.org,
	Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 2/2] KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
Date: Fri, 16 Jul 2021 12:43:10 +1000	[thread overview]
Message-ID: <20210716024310.164448-2-npiggin@gmail.com> (raw)
In-Reply-To: <20210716024310.164448-1-npiggin@gmail.com>

vcpu_put is not called if the user copy fails. This can result in preempt
notifier corruption and crashes, among other issues.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Fixes: b3cebfe8c1ca ("KVM: PPC: Move vcpu_load/vcpu_put down to each ioctl case in kvm_arch_vcpu_ioctl")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kvm/powerpc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index be33b5321a76..b4e6f70b97b9 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -2048,9 +2048,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	{
 		struct kvm_enable_cap cap;
 		r = -EFAULT;
-		vcpu_load(vcpu);
 		if (copy_from_user(&cap, argp, sizeof(cap)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
 		vcpu_put(vcpu);
 		break;
@@ -2074,9 +2074,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	case KVM_DIRTY_TLB: {
 		struct kvm_dirty_tlb dirty;
 		r = -EFAULT;
-		vcpu_load(vcpu);
 		if (copy_from_user(&dirty, argp, sizeof(dirty)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_vcpu_ioctl_dirty_tlb(vcpu, &dirty);
 		vcpu_put(vcpu);
 		break;
-- 
2.23.0


WARNING: multiple messages have this Message-ID (diff)
From: Nicholas Piggin <npiggin@gmail.com>
To: kvm-ppc@vger.kernel.org
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
	linuxppc-dev@lists.ozlabs.org,
	Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 2/2] KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
Date: Fri, 16 Jul 2021 02:43:10 +0000	[thread overview]
Message-ID: <20210716024310.164448-2-npiggin@gmail.com> (raw)
In-Reply-To: <20210716024310.164448-1-npiggin@gmail.com>

vcpu_put is not called if the user copy fails. This can result in preempt
notifier corruption and crashes, among other issues.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Fixes: b3cebfe8c1ca ("KVM: PPC: Move vcpu_load/vcpu_put down to each ioctl case in kvm_arch_vcpu_ioctl")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kvm/powerpc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index be33b5321a76..b4e6f70b97b9 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -2048,9 +2048,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	{
 		struct kvm_enable_cap cap;
 		r = -EFAULT;
-		vcpu_load(vcpu);
 		if (copy_from_user(&cap, argp, sizeof(cap)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_vcpu_ioctl_enable_cap(vcpu, &cap);
 		vcpu_put(vcpu);
 		break;
@@ -2074,9 +2074,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 	case KVM_DIRTY_TLB: {
 		struct kvm_dirty_tlb dirty;
 		r = -EFAULT;
-		vcpu_load(vcpu);
 		if (copy_from_user(&dirty, argp, sizeof(dirty)))
 			goto out;
+		vcpu_load(vcpu);
 		r = kvm_vcpu_ioctl_dirty_tlb(vcpu, &dirty);
 		vcpu_put(vcpu);
 		break;
-- 
2.23.0

  reply	other threads:[~2021-07-16  2:44 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16  2:43 [PATCH 1/2] KVM: PPC: Book3S: Fix CONFIG_TRANSACTIONAL_MEM=n crash Nicholas Piggin
2021-07-16  2:43 ` Nicholas Piggin
2021-07-16  2:43 ` Nicholas Piggin [this message]
2021-07-16  2:43   ` [PATCH 2/2] KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak Nicholas Piggin
2021-07-21  7:38 ` [PATCH 1/2] KVM: PPC: Book3S: Fix CONFIG_TRANSACTIONAL_MEM=n crash Michael Ellerman
2021-07-21  7:38   ` Michael Ellerman

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