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KVM: arm64: vgic-v2: Check for non-NULL vCPU in vgic_v2_parse_attr() 

[ Upstream commit 6ddb4f372fc63210034b903d96ebbeb3c7195adb ]

Fix CVE: CVE-2024-36953

vgic_v2_parse_attr() is responsible for finding the vCPU that matches
the user-provided CPUID, which (of course) may not be valid. If the ID
is invalid, kvm_get_vcpu_by_id() returns NULL, which isn't handled
gracefully.

Similar to the GICv3 uaccess flow, check that kvm_get_vcpu_by_id()
actually returns something and fail the ioctl if not.

Cc: stable@vger.kernel.org
Fixes: 7d450e2821 ("KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers")
Reported-by: Alexander Potapenko <glider@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240424173959.3776798-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jianping Liu <frankjpliu@tencent.com>
This commit is contained in:
Oliver Upton 2024-06-05 20:32:06 +08:00 committed by Jianping Liu
parent aaf8f5dafe
commit 91ccae1327
1 changed files with 3 additions and 1 deletions
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4
virt/kvm/arm/vgic/vgic-kvm-device.c
View File

@ -289,8 +289,10 @@ int vgic_v2_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr,
if (cpuid >= atomic_read(&dev->kvm->online_vcpus))
return -EINVAL;
reg_attr->vcpu = kvm_get_vcpu(dev->kvm, cpuid);
reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;
reg_attr->vcpu = kvm_get_vcpu(dev->kvm, cpuid);
if (!reg_attr->vcpu)
return -EINVAL;
return 0;
}