155 lines
4.8 KiB
Diff
155 lines
4.8 KiB
Diff
From d26c25a9d19b5976b319af528886f89cf455692d Mon Sep 17 00:00:00 2001
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From: Dave Martin <Dave.Martin@arm.com>
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Date: Thu, 27 Sep 2018 16:53:21 +0100
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Subject: arm64: KVM: Tighten guest core register access from userspace
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From: Dave Martin <Dave.Martin@arm.com>
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commit d26c25a9d19b5976b319af528886f89cf455692d upstream.
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We currently allow userspace to access the core register file
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in about any possible way, including straddling multiple
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registers and doing unaligned accesses.
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This is not the expected use of the ABI, and nobody is actually
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using it that way. Let's tighten it by explicitly checking
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the size and alignment for each field of the register file.
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Cc: <stable@vger.kernel.org>
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Fixes: 2f4a07c5f9fe ("arm64: KVM: guest one-reg interface")
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Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
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Reviewed-by: Mark Rutland <mark.rutland@arm.com>
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Signed-off-by: Dave Martin <Dave.Martin@arm.com>
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[maz: rewrote Dave's initial patch to be more easily backported]
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Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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Signed-off-by: Will Deacon <will.deacon@arm.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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arch/arm64/kvm/guest.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
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1 file changed, 45 insertions(+)
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--- a/arch/arm64/kvm/guest.c
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+++ b/arch/arm64/kvm/guest.c
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@@ -57,6 +57,45 @@ static u64 core_reg_offset_from_id(u64 i
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return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE);
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}
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+static int validate_core_offset(const struct kvm_one_reg *reg)
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+{
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+ u64 off = core_reg_offset_from_id(reg->id);
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+ int size;
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+
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+ switch (off) {
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+ case KVM_REG_ARM_CORE_REG(regs.regs[0]) ...
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+ KVM_REG_ARM_CORE_REG(regs.regs[30]):
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+ case KVM_REG_ARM_CORE_REG(regs.sp):
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+ case KVM_REG_ARM_CORE_REG(regs.pc):
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+ case KVM_REG_ARM_CORE_REG(regs.pstate):
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+ case KVM_REG_ARM_CORE_REG(sp_el1):
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+ case KVM_REG_ARM_CORE_REG(elr_el1):
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+ case KVM_REG_ARM_CORE_REG(spsr[0]) ...
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+ KVM_REG_ARM_CORE_REG(spsr[KVM_NR_SPSR - 1]):
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+ size = sizeof(__u64);
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+ break;
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+
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+ case KVM_REG_ARM_CORE_REG(fp_regs.vregs[0]) ...
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+ KVM_REG_ARM_CORE_REG(fp_regs.vregs[31]):
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+ size = sizeof(__uint128_t);
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+ break;
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+
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+ case KVM_REG_ARM_CORE_REG(fp_regs.fpsr):
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+ case KVM_REG_ARM_CORE_REG(fp_regs.fpcr):
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+ size = sizeof(__u32);
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+ break;
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+
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+ default:
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+ return -EINVAL;
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+ }
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+
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+ if (KVM_REG_SIZE(reg->id) == size &&
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+ IS_ALIGNED(off, size / sizeof(__u32)))
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+ return 0;
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+
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+ return -EINVAL;
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+}
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+
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static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
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{
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/*
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@@ -76,6 +115,9 @@ static int get_core_reg(struct kvm_vcpu
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(off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
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return -ENOENT;
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+ if (validate_core_offset(reg))
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+ return -EINVAL;
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+
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if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id)))
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return -EFAULT;
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@@ -98,6 +140,9 @@ static int set_core_reg(struct kvm_vcpu
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(off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
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return -ENOENT;
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+ if (validate_core_offset(reg))
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+ return -EINVAL;
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+
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if (KVM_REG_SIZE(reg->id) > sizeof(tmp))
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return -EINVAL;
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From 2a3f93459d689d990b3ecfbe782fec89b97d3279 Mon Sep 17 00:00:00 2001
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From: Marc Zyngier <marc.zyngier@arm.com>
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Date: Thu, 27 Sep 2018 16:53:22 +0100
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Subject: arm64: KVM: Sanitize PSTATE.M when being set from userspace
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From: Marc Zyngier <marc.zyngier@arm.com>
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commit 2a3f93459d689d990b3ecfbe782fec89b97d3279 upstream.
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Not all execution modes are valid for a guest, and some of them
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depend on what the HW actually supports. Let's verify that what
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userspace provides is compatible with both the VM settings and
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the HW capabilities.
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Cc: <stable@vger.kernel.org>
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Fixes: 0d854a60b1d7 ("arm64: KVM: enable initialization of a 32bit vcpu")
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Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
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Reviewed-by: Mark Rutland <mark.rutland@arm.com>
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Reviewed-by: Dave Martin <Dave.Martin@arm.com>
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Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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Signed-off-by: Will Deacon <will.deacon@arm.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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arch/arm64/kvm/guest.c | 10 +++++++++-
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1 file changed, 9 insertions(+), 1 deletion(-)
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--- a/arch/arm64/kvm/guest.c
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+++ b/arch/arm64/kvm/guest.c
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@@ -152,17 +152,25 @@ static int set_core_reg(struct kvm_vcpu
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}
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if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) {
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- u32 mode = (*(u32 *)valp) & COMPAT_PSR_MODE_MASK;
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+ u64 mode = (*(u64 *)valp) & COMPAT_PSR_MODE_MASK;
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switch (mode) {
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case COMPAT_PSR_MODE_USR:
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+ if (!system_supports_32bit_el0())
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+ return -EINVAL;
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+ break;
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case COMPAT_PSR_MODE_FIQ:
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case COMPAT_PSR_MODE_IRQ:
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case COMPAT_PSR_MODE_SVC:
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case COMPAT_PSR_MODE_ABT:
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case COMPAT_PSR_MODE_UND:
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+ if (!vcpu_el1_is_32bit(vcpu))
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+ return -EINVAL;
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+ break;
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case PSR_MODE_EL0t:
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case PSR_MODE_EL1t:
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case PSR_MODE_EL1h:
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+ if (vcpu_el1_is_32bit(vcpu))
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+ return -EINVAL;
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break;
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default:
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err = -EINVAL;
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