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Commit 1713e5aa authored by Marc Zyngier's avatar Marc Zyngier
Browse files

arm64: KVM: Fix user access for debug registers 



When setting the debug register from userspace, make sure that
copy_from_user() is called with its parameters in the expected
order. It otherwise doesn't do what you think.

Fixes: 84e690bf ("KVM: arm64: introduce vcpu->arch.debug_ptr")
Reported-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Cc: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 43297dda

arch/arm64/kvm/sys_regs.c

+4 −4
Original line number Diff line number Diff line
@@ -272,7 +272,7 @@ static int set_bvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, 
{

	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bvr[rd->reg];



	if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)

	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)

		return -EFAULT;

	return 0;

}
@@ -314,7 +314,7 @@ static int set_bcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, 
{

	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_bcr[rd->reg];



	if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)

	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)

		return -EFAULT;



	return 0;
@@ -358,7 +358,7 @@ static int set_wvr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, 
{

	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wvr[rd->reg];



	if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)

	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)

		return -EFAULT;

	return 0;

}
@@ -400,7 +400,7 @@ static int set_wcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, 
{

	__u64 *r = &vcpu->arch.vcpu_debug_state.dbg_wcr[rd->reg];



	if (copy_from_user(uaddr, r, KVM_REG_SIZE(reg->id)) != 0)

	if (copy_from_user(r, uaddr, KVM_REG_SIZE(reg->id)) != 0)

		return -EFAULT;

	return 0;

}