From 4b9e92983e4ec700dbf475ee6b019ac51f408280 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 27 Sep 2023 17:09:04 +0800 Subject: [PATCH 1/2] KVM: arm64: vgic-v2: Use cpuid from userspace as vcpu_id ANBZ: #12829 commit 4563a0afd99e1d86acb7d54a0809ed27d273a7f6 stable. commit 4e7728c81a54b17bd33be402ac140bc11bb0c4f4 upstream. 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 Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230927090911.3355209-5-maz@kernel.org Signed-off-by: Oliver Upton Stable-dep-of: 6ddb4f372fc6 ("KVM: arm64: vgic-v2: Check for non-NULL vCPU in vgic_v2_parse_attr()") Signed-off-by: Sasha Levin Fixes: CVE-2024-36953 Signed-off-by: Xiao Long Signed-off-by: Qinyun Tan --- arch/arm64/kvm/vgic/vgic-kvm-device.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c index 7740995de982..640cfa0c0f4c 100644 --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c @@ -286,13 +286,9 @@ int vgic_v2_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr, { int cpuid; - cpuid = (attr->attr & KVM_DEV_ARM_VGIC_CPUID_MASK) >> - KVM_DEV_ARM_VGIC_CPUID_SHIFT; + cpuid = FIELD_GET(KVM_DEV_ARM_VGIC_CPUID_MASK, attr->attr); - if (cpuid >= atomic_read(&dev->kvm->online_vcpus)) - return -EINVAL; - - reg_attr->vcpu = kvm_get_vcpu(dev->kvm, cpuid); + reg_attr->vcpu = kvm_get_vcpu_by_id(dev->kvm, cpuid); reg_attr->addr = attr->attr & KVM_DEV_ARM_VGIC_OFFSET_MASK; return 0; -- Gitee From 03179cc5f1a888b477cc232484e65de5a99d8adf Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Thu, 25 Apr 2024 01:39:58 +0800 Subject: [PATCH 2/2] KVM: arm64: vgic-v2: Check for non-NULL vCPU in vgic_v2_parse_attr() ANBZ: #12829 commit 4404465a1bee3607ad90a4c5f9e16dfd75b85728 stable. commit 6ddb4f372fc63210034b903d96ebbeb3c7195adb upstream. 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 Fixes: CVE-2024-36953 Signed-off-by: Xiao Long Signed-off-by: Qinyun Tan --- 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 640cfa0c0f4c..e80b638b7827 100644 --- a/arch/arm64/kvm/vgic/vgic-kvm-device.c +++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c @@ -284,12 +284,12 @@ 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; } -- Gitee