From: Nicholas Piggin npiggin@gmail.com

stable inclusion from stable-v5.10.54 commit e14ef1095387f764d95614d3ec9e4d07c82a3533 bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9R4H1 CVE: CVE-2021-47296

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream 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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Signed-off-by: Zheng Zucheng zhengzucheng@huawei.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 ee89f6fbea86..b9df096bfae9 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -1994,9 +1994,9 @@ 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; @@ -2020,9 +2020,9 @@ 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;