From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 5766630E84D for ; Mon, 8 Sep 2025 23:54:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757375665; cv=none; b=ERwr5b7csuepODEAl1bsoMjSaAkPyoNiBrGfo2g9yQx/hHASFkx4jgDKRXY+4waCfNRtFCs6UWoC1Gq1UTYox7RL+nLDbZaVVaoVwQ/CPHZm1++VUuG9NYDwxESzpyfe63nHM70IJtONdIaNOsXUgMsOGK/AYUxdWE/sXpEJzxY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757375665; c=relaxed/simple; bh=nqQiLGDt4E8Jq4QZSeVe7zoFw3b3ODJL8vpKGUrpq1Y=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=P4vk3EQ5fLdFZRzsYZbS1kEZPtiPB1Sa1t2v20DbbCVVEZwKYOY7CHUl1v817MJxio+h9mmK7CQ42mGEEzJvam1GSK+604HCbJW7ggm80tPv51HqaMnggQn62ltf4TdPVEpDud6SBUPxHq80K1SRbXY0/PLZoFxYae1YuUUXE9c= 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=D4UtkBDx; arc=none smtp.client-ip=209.85.210.201 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="D4UtkBDx" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-77278d3789cso10837546b3a.1 for ; Mon, 08 Sep 2025 16:54:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757375663; x=1757980463; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=K/rfS9/CYErQEW8MvIwXJiXzKk2lG6NUVw07jdOfv2E=; b=D4UtkBDx6kewgzUqBGgAizUJQL+gilwW6/qUW7e1sW9aLGQQJrdZI/uSXgJCkfEsok BxXjOZVcva7pGHmBk6fyDs8VvDQm0KHaWgZWAfrT+BZahGLSBNk2fibvaOeHXJLmQkH1 /gJhA+PUgHl+TV93h2958FIIvV6+PqLKUtlXZPPYQUR+0lXvnb6aw03Lm6G9TDS+ua0f yBG3oVWlZHr/eyz43zxB6Fwj4xXSaEwbh8FYRpAW9zsRIMmWjLloCnX5yomvCKf/2HYf kTJTbvZcVH7t4a+PbxM9FC3gAaB99cU7SmecDa4l5X2IrsJXJ1jQk9UivSx2CaL3htFY IgdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757375663; x=1757980463; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=K/rfS9/CYErQEW8MvIwXJiXzKk2lG6NUVw07jdOfv2E=; b=kZwhie3rapDGzXgayFttKfmCc88YTZ0A8IH/8yl63raW1e28C7JNAsWIHl1XYbzOS5 EQbBigc2lcHb2m8VkdUJAcqslMt4ytfOOCU+VjHpmedS3ElxaIpbDOX4ZCyJEeWzHzd1 o0G6vefqiRN9F8VuNVRbbharqysTur/9xxXHp4oVTeFNeN4EXcQs+wIxxBeliqsjbvGo 6fMVdSHHbbfDoTuxLNFIIpquh5yC7bly0Kwx0wUu3Zxul6baZO+3z1HbBpU91GCqAmLC gHOe2tIf4Ra126EIWnf5lAmWs23cPAolMUiP7x9ObqZWm5AolXb6+iBL2Pqvu0hUXoOd u17w== X-Forwarded-Encrypted: i=1; AJvYcCXEXVxji3FlP7F4aNC83z5796S1Obgdl0seM0mNRC8OY8hUTnmIiwu3PtGT6YofOpt27xY=@vger.kernel.org X-Gm-Message-State: AOJu0YzHk/2tq86dU+XAllkSI9Zu5jVAJCStvaH6uXaOAl2yhOQI7jSR LNQn64e+A3JISpQZ3n1ATbSKnFLEvHiQYbrPz9IIPpHkYb4UDuzR03wxJDqiZHyn5IBQnHmfaMC /xjsbug== X-Google-Smtp-Source: AGHT+IHFuX9HZZ+3Ap9KfIP9YqmTsis1lj1RdPwzOjpZRGAUvoQwOVBBtSltO2l5sj1D1kqm/ucDlsqS4As= X-Received: from pfet12.prod.google.com ([2002:aa7:938c:0:b0:772:32b1:58f9]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:1394:b0:771:ef79:9338 with SMTP id d2e1a72fcca58-7742def5d1emr11472262b3a.21.1757375663426; Mon, 08 Sep 2025 16:54:23 -0700 (PDT) Date: Mon, 8 Sep 2025 16:54:21 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250826233734.4011090-1-seanjc@google.com> Message-ID: Subject: Re: [PATCH] KVM: SEV: Reject non-positive effective lengths during LAUNCH_UPDATE From: Sean Christopherson To: Tom Lendacky Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Roth Content-Type: text/plain; charset="us-ascii" On Mon, Sep 08, 2025, Tom Lendacky wrote: > On 8/26/25 18:37, Sean Christopherson wrote: > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > > index f4381878a9e5..746a57bf1f71 100644 > > --- a/arch/x86/kvm/svm/sev.c > > +++ b/arch/x86/kvm/svm/sev.c > > @@ -2360,6 +2360,8 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) > > return -EINVAL; > > > > npages = params.len / PAGE_SIZE; > > + if (npages <= 0) > > + return -EINVAL; > > Would it make sense to include a !params.len in the giant if check just > above this, e.g.: > > if (!params.len || !PAGE_ALIGNED(params.len) || ... > > ? > > That way everything related to checking "params" remains in the one > statement. Oh, yeah, duh. I overlooked that the only way for npages to be '0' is if params.len is '0', because the PAGE_ALIGNED() check will handed len == 1-4095. Will send a v2. Thanks Tom!