From bc4188a2f56e821ea057aca6bf444e138d06c252 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Fri, 16 Jul 2021 12:43:10 +1000
Subject: [PATCH] KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
References: bsc#1156395
Patch-mainline: v5.14-rc3
Git-commit: bc4188a2f56e821ea057aca6bf444e138d06c252
vcpu_put is not called if the user copy fails. This can result in preempt
notifier corruption and crashes, among other issues.
Fixes: b3cebfe8c1ca ("KVM: PPC: Move vcpu_load/vcpu_put down to each ioctl case in kvm_arch_vcpu_ioctl")
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210716024310.164448-2-npiggin@gmail.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
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;
--
2.31.1