Commit 6ddb4f37 authored by Oliver Upton's avatar Oliver Upton
Browse files

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



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: 7d450e28 ("KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers")
Reported-by: default avatarAlexander Potapenko <glider@google.com>
Tested-by: default avatarAlexander Potapenko <glider@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240424173959.3776798-2-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent fec50db7

arch/arm64/kvm/vgic/vgic-kvm-device.c

+4 −4
Original line number Diff line number Diff line
@@ -338,12 +338,12 @@ int kvm_register_vgic_device(unsigned long type) 
int vgic_v2_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr,

		       struct vgic_reg_attr *reg_attr)

{

	int cpuid;

	int cpuid = FIELD_GET(KVM_DEV_ARM_VGIC_CPUID_MASK, attr->attr);



	cpuid = FIELD_GET(KVM_DEV_ARM_VGIC_CPUID_MASK, attr->attr);



	reg_attr->vcpu = kvm_get_vcpu_by_id(dev->kvm, cpuid);

	reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK;

	reg_attr->vcpu = kvm_get_vcpu_by_id(dev->kvm, cpuid);

	if (!reg_attr->vcpu)

		return -EINVAL;



	return 0;

}