From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 00AE048B374 for ; Thu, 6 Aug 2026 17:06:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786035969; cv=none; b=umpm7/44qq3LS/hog6iIy24NKCYtHNqHB8ABdTwBIyzaebrTlrHzYG862nKELGvP6+aFV+365IQ8mMTXD7WGeFQAyT67dskABbVc/0mcPJqGisk6TyHOHwMnDIa4R8Iyt9pVx0zOBkWrijHnFXSUwllNtMq7gFIbal13rBpoFiY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786035969; c=relaxed/simple; bh=8QsSGiEAaqCQy0cZvG0XEQmjL6NBrQ5rQlcU3Mw2rGw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=eag3gyNJ1uJL9eCbLX7HSR8SKuFpsUlZBkJPaKcbfQViwP2zI9/OCP3C5WeiuQ3mqfOifUAyuTfulXV26D0ZkDsCD0ayoiWaVYzHQYRnNI4cQcwfyewnvWejEjy2EBeCh7IXwqMQ3HMYdbS87+i75D1lLcMdLl34lvAITH1q8/I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=fP2iZSTF; arc=none smtp.client-ip=209.85.215.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fP2iZSTF" Received: by mail-pg1-f200.google.com with SMTP id 41be03b00d2f7-c89704da8c7so3498895a12.0 for ; Thu, 06 Aug 2026 10:06:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786035967; x=1786640767; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=aIw+FKSYh9yZePv09d+Ay5MUcxdlIRKZjplIOJy/wbw=; b=fP2iZSTFxkuWhjT+jkV2Rf/pnBgK4ScRDqtybDhg8DKOLjLQmBja6qzROtKTvG8J3v 6OM3D2kgZA8puRH1QgmGsWT4+H1tM+iiZpEiMD1PjfXefUrYH1hu6Kt1O+K2z93UBgFC X4dcdlufB9CXLu995WsO9QFKIE+kqyvt6D5D/RR/JTUFqWyoXyAOEuCMa7qc0n18AEEI 3baIz55hTn3e79wjTJBtUFuqEcV/6RWAbCFWdNwd23EBYc8Tkhr6LwiVfYJjGpdedSIo 8Zm6i6OmMyAPlAEV/X6UxRFnlA7K7C7Mm5DAs9d40KTrFAm1wVx5uaCSvkIi466c5I3W opIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786035967; x=1786640767; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=aIw+FKSYh9yZePv09d+Ay5MUcxdlIRKZjplIOJy/wbw=; b=ZKTY/QOdBu4wJ2cj+rPiOp3eMvTij7S00SAsu7H/+c8ZPbNOtFpO9DTMTZiv+PS2rU fUkApEmc/kU/WmFc6NrXXj0OoO8LXXwcgEcttP9Ufc7Q5XYCKqSA3UWVeKYWdGbRTjSi RiGn9q+4sDmxgfIXfuUBlhndKt3be5mXbflBMgrkF6HKj5aFhh02p4gGEdM5WPS9uQSO OTbLSjeHD3uu2C7RJ+UheplEWB9WuhAuYY9/XhpMGHiuCxVKGofEe0r24booPkl/uImG vJVk7QTYX/r898TrWOLzBPEPnJXd3dEla4LUM/PgtBW6JyPb9ENbSFHDliUOtRiL8zFr gdAw== X-Gm-Message-State: AOJu0YyWKiwAjNj11OdHuFG722HtRBIZfhntpM+XUPawz5HoRJi4wkD9 7EQH0ilTtV5NDTLTxukjftE9ttFzgbzLlum8WENII9McQCwwUUDmxPpSRw9q5nAFbe/X1qOkygD 1MZcKIQ== X-Received: from pghu18.prod.google.com ([2002:a63:ef12:0:b0:c98:2639:852c]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:164a:b0:3c3:a08d:5b44 with SMTP id adf61e73a8af0-3cb85ef9234mr20536509637.23.1786035967107; Thu, 06 Aug 2026 10:06:07 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 6 Aug 2026 10:06:02 -0700 In-Reply-To: <20260806170602.4112602-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260806170602.4112602-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.679.g6767b8d81c-goog Message-ID: <20260806170602.4112602-3-seanjc@google.com> Subject: [PATCH v2 2/2] KVM: TDX: Fix a benign off-by-one bug on the end GPA for INIT_MEM_REGION From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Sashiko Bot , Yan Zhao , Binbin Wu , Ackerley Tng , Haotian Jiang Content-Type: text/plain; charset="UTF-8" When verifying that the incoming GPA rage for INIT_MEM_REGION doesn't wrap, check the inclusive last GPA, not the exclusive last GPA. Super duper technically, it's ok if the very last GPA is -1ull. In practice, the flaw is benign as KVM x86 disallows memslots with GPAs that exceed MAXPHYADDR, i.e. INIT_MEM_REGION would fail with -EINVAL anyways due to the memslot check in kvm_gmem_populate(). Opportunistically use check_add_overflow() instead of manually checking for wrap, mostly so that the inclusive math doesn't need to be copy+pasted in the "is private" check. Fixes: c846b451d3c5 ("KVM: TDX: Add an ioctl to create initial guest memory") Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/tdx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 929115aeb9ec..85699ea021fe 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -3219,7 +3219,7 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm); struct kvm_tdx_init_mem_region region; struct tdx_gmem_post_populate_arg arg; - gpa_t nr_bytes; + gpa_t nr_bytes, end_gpa; long gmem_ret; int ret; @@ -3241,9 +3241,9 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c return -EINVAL; if (check_shl_overflow(region.nr_pages, PAGE_SHIFT, &nr_bytes) || - region.gpa + nr_bytes <= region.gpa || + check_add_overflow(region.gpa, nr_bytes - 1, &end_gpa) || !vt_is_tdx_private_gpa(kvm, region.gpa) || - !vt_is_tdx_private_gpa(kvm, region.gpa + nr_bytes - 1)) + !vt_is_tdx_private_gpa(kvm, end_gpa)) return -EINVAL; ret = 0; -- 2.55.0.679.g6767b8d81c-goog