linux-kernel - [PATCH v3 21/25] KVM: TDX: Add tdx_get_cmd() helper to get and validate sub-ioctl command

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251017003244.186495-22-seanjc@google.com>
Date: Thu, 16 Oct 2025 17:32:39 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Tianrui Zhao <zhaotianrui@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>, 
	Huacai Chen <chenhuacai@...nel.org>, Madhavan Srinivasan <maddy@...ux.ibm.com>, 
	Anup Patel <anup@...infault.org>, Paul Walmsley <pjw@...nel.org>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
	Christian Borntraeger <borntraeger@...ux.ibm.com>, Janosch Frank <frankja@...ux.ibm.com>, 
	Claudio Imbrenda <imbrenda@...ux.ibm.com>, Sean Christopherson <seanjc@...gle.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, "Kirill A. Shutemov" <kas@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
	kvm@...r.kernel.org, loongarch@...ts.linux.dev, linux-mips@...r.kernel.org, 
	linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org, 
	linux-riscv@...ts.infradead.org, x86@...nel.org, linux-coco@...ts.linux.dev, 
	linux-kernel@...r.kernel.org, Ira Weiny <ira.weiny@...el.com>, 
	Kai Huang <kai.huang@...el.com>, Michael Roth <michael.roth@....com>, 
	Yan Zhao <yan.y.zhao@...el.com>, Vishal Annapurve <vannapurve@...gle.com>, 
	Rick Edgecombe <rick.p.edgecombe@...el.com>, Ackerley Tng <ackerleytng@...gle.com>, 
	Binbin Wu <binbin.wu@...ux.intel.com>
Subject: [PATCH v3 21/25] KVM: TDX: Add tdx_get_cmd() helper to get and
 validate sub-ioctl command

Add a helper to copy a kvm_tdx_cmd structure from userspace and verify
that must-be-zero fields are indeed zero.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/vmx/tdx.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 2e2dab89c98f..d5f810435f34 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2761,20 +2761,25 @@ static int tdx_td_finalize(struct kvm *kvm, struct kvm_tdx_cmd *cmd)
 	return 0;
 }
 
+static int tdx_get_cmd(void __user *argp, struct kvm_tdx_cmd *cmd)
+{
+	if (copy_from_user(cmd, argp, sizeof(*cmd)))
+		return -EFAULT;
+
+	if (cmd->hw_error)
+		return -EINVAL;
+
+	return 0;
+}
+
 int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
 {
 	struct kvm_tdx_cmd tdx_cmd;
 	int r;
 
-	if (copy_from_user(&tdx_cmd, argp, sizeof(struct kvm_tdx_cmd)))
-		return -EFAULT;
-
-	/*
-	 * Userspace should never set hw_error. It is used to fill
-	 * hardware-defined error by the kernel.
-	 */
-	if (tdx_cmd.hw_error)
-		return -EINVAL;
+	r = tdx_get_cmd(argp, &tdx_cmd);
+	if (r)
+		return r;
 
 	mutex_lock(&kvm->lock);
 
@@ -3152,11 +3157,9 @@ int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
 	if (!is_hkid_assigned(kvm_tdx) || kvm_tdx->state == TD_STATE_RUNNABLE)
 		return -EINVAL;
 
-	if (copy_from_user(&cmd, argp, sizeof(cmd)))
-		return -EFAULT;
-
-	if (cmd.hw_error)
-		return -EINVAL;
+	ret = tdx_get_cmd(argp, &cmd);
+	if (ret)
+		return ret;
 
 	switch (cmd.id) {
 	case KVM_TDX_INIT_VCPU:
-- 
2.51.0.858.gf9c4a03a3a-goog