[ 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 <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>
[ Upstream commit 4e7728c81a54b17bd33be402ac140bc11bb0c4f4 ]
When parsing a GICv2 attribute that contains a cpuid, handle this
as the vcpu_id, not a vcpu_idx, as userspace cannot really know
the mapping between the two. For this, use kvm_get_vcpu_by_id()
instead of kvm_get_vcpu().
Take this opportunity to get rid of the pointless check against
online_vcpus, which doesn't make much sense either, and switch
to FIELD_GET as a way to extract the vcpu_id.
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230927090911.3355209-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Stable-dep-of: 6ddb4f372fc6 ("KVM: arm64: vgic-v2: Check for non-NULL vCPU in vgic_v2_parse_attr()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
