From: Marc Zyngier <marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Andre Przywara <andre.przywara@arm.com>, Christoffer Dall <christoffer.dall@linaro.org>, James Morse <james.morse@arm.com> Subject: [PATCH] KVM: arm/arm64: vgic: Prevent access to invalid SPIs Date: Fri, 28 Oct 2016 11:28:18 +0100 [thread overview] Message-ID: <1477650498-19200-1-git-send-email-marc.zyngier@arm.com> (raw) From: Andre Przywara <andre.przywara@arm.com> In our VGIC implementation we limit the number of SPIs to a number that the userland application told us. Accordingly we limit the allocation of memory for virtual IRQs to that number. However in our MMIO dispatcher we didn't check if we ever access an IRQ beyond that limit, leading to out-of-bound accesses. Add a test against the number of allocated SPIs in check_region(). [maz: cleaned-up original patch] Cc: stable@vger.kernel.org Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/vgic/vgic-mmio.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 14 deletions(-) diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c index e18b30d..ebe1b9f 100644 --- a/virt/kvm/arm/vgic/vgic-mmio.c +++ b/virt/kvm/arm/vgic/vgic-mmio.c @@ -453,17 +453,33 @@ struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev) return container_of(dev, struct vgic_io_device, dev); } -static bool check_region(const struct vgic_register_region *region, +static bool check_region(const struct kvm *kvm, + const struct vgic_register_region *region, gpa_t addr, int len) { - if ((region->access_flags & VGIC_ACCESS_8bit) && len == 1) - return true; - if ((region->access_flags & VGIC_ACCESS_32bit) && - len == sizeof(u32) && !(addr & 3)) - return true; - if ((region->access_flags & VGIC_ACCESS_64bit) && - len == sizeof(u64) && !(addr & 7)) - return true; + int flags, nr_irqs = kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS; + + switch (len) { + case sizeof(u8): + flags = VGIC_ACCESS_8bit; + break; + case sizeof(u32): + flags = VGIC_ACCESS_32bit; + break; + case sizeof(u64): + flags = VGIC_ACCESS_64bit; + break; + default: + return false; + } + + if ((region->access_flags & flags) && IS_ALIGNED(addr, len)) { + if (!region->bits_per_irq) + return true; + + /* Do we access a non-allocated IRQ? */ + return VGIC_ADDR_TO_INTID(addr, region->bits_per_irq) < nr_irqs; + } return false; } @@ -477,7 +493,7 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions, addr - iodev->base_addr); - if (!region || !check_region(region, addr, len)) { + if (!region || !check_region(vcpu->kvm, region, addr, len)) { memset(val, 0, len); return 0; } @@ -510,10 +526,7 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions, addr - iodev->base_addr); - if (!region) - return 0; - - if (!check_region(region, addr, len)) + if (!region || !check_region(vcpu->kvm, region, addr, len)) return 0; switch (iodev->iodev_type) { -- 2.1.4
WARNING: multiple messages have this Message-ID (diff)
From: marc.zyngier@arm.com (Marc Zyngier) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] KVM: arm/arm64: vgic: Prevent access to invalid SPIs Date: Fri, 28 Oct 2016 11:28:18 +0100 [thread overview] Message-ID: <1477650498-19200-1-git-send-email-marc.zyngier@arm.com> (raw) From: Andre Przywara <andre.przywara@arm.com> In our VGIC implementation we limit the number of SPIs to a number that the userland application told us. Accordingly we limit the allocation of memory for virtual IRQs to that number. However in our MMIO dispatcher we didn't check if we ever access an IRQ beyond that limit, leading to out-of-bound accesses. Add a test against the number of allocated SPIs in check_region(). [maz: cleaned-up original patch] Cc: stable at vger.kernel.org Signed-off-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> --- virt/kvm/arm/vgic/vgic-mmio.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 14 deletions(-) diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c index e18b30d..ebe1b9f 100644 --- a/virt/kvm/arm/vgic/vgic-mmio.c +++ b/virt/kvm/arm/vgic/vgic-mmio.c @@ -453,17 +453,33 @@ struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev) return container_of(dev, struct vgic_io_device, dev); } -static bool check_region(const struct vgic_register_region *region, +static bool check_region(const struct kvm *kvm, + const struct vgic_register_region *region, gpa_t addr, int len) { - if ((region->access_flags & VGIC_ACCESS_8bit) && len == 1) - return true; - if ((region->access_flags & VGIC_ACCESS_32bit) && - len == sizeof(u32) && !(addr & 3)) - return true; - if ((region->access_flags & VGIC_ACCESS_64bit) && - len == sizeof(u64) && !(addr & 7)) - return true; + int flags, nr_irqs = kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS; + + switch (len) { + case sizeof(u8): + flags = VGIC_ACCESS_8bit; + break; + case sizeof(u32): + flags = VGIC_ACCESS_32bit; + break; + case sizeof(u64): + flags = VGIC_ACCESS_64bit; + break; + default: + return false; + } + + if ((region->access_flags & flags) && IS_ALIGNED(addr, len)) { + if (!region->bits_per_irq) + return true; + + /* Do we access a non-allocated IRQ? */ + return VGIC_ADDR_TO_INTID(addr, region->bits_per_irq) < nr_irqs; + } return false; } @@ -477,7 +493,7 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions, addr - iodev->base_addr); - if (!region || !check_region(region, addr, len)) { + if (!region || !check_region(vcpu->kvm, region, addr, len)) { memset(val, 0, len); return 0; } @@ -510,10 +526,7 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev, region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions, addr - iodev->base_addr); - if (!region) - return 0; - - if (!check_region(region, addr, len)) + if (!region || !check_region(vcpu->kvm, region, addr, len)) return 0; switch (iodev->iodev_type) { -- 2.1.4
next reply other threads:[~2016-10-28 10:28 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-10-28 10:28 Marc Zyngier [this message] 2016-10-28 10:28 ` [PATCH] KVM: arm/arm64: vgic: Prevent access to invalid SPIs Marc Zyngier
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