From 3a5b0378ac6776c7c31b18e0f3c1389bd6005e80 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 24 Apr 2024 17:39:58 +0000 Subject: [PATCH] KVM: arm64: vgic-v2: Check for non-NULL vCPU in vgic_v2_parse_attr() [ Upstream commit 6ddb4f372fc63210034b903d96ebbeb3c7195adb ] 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: 7d450e282171 ("KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers") Reported-by: Alexander Potapenko Tested-by: Alexander Potapenko Reviewed-by: Alexander Potapenko Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20240424173959.3776798-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton Signed-off-by: Sasha Levin --- arch/arm64/kvm/vgic/vgic-kvm-device.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c index 97ead28f8142..63731fb3d8f6 100644 --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c @@ -337,12 +337,12 @@ 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; }