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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: 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>
This commit is contained in:
Oliver Upton 2024-04-24 17:39:58 +00:00
parent fec50db703
commit 6ddb4f372f
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/arm64/kvm/vgic/vgic-kvm-device.c
View File

@ -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;
}