From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04BF9C433E0 for ; Wed, 13 Jan 2021 20:46:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3D8723107 for ; Wed, 13 Jan 2021 20:46:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728938AbhAMUqA (ORCPT ); Wed, 13 Jan 2021 15:46:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727945AbhAMUqA (ORCPT ); Wed, 13 Jan 2021 15:46:00 -0500 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FAF8C061786 for ; Wed, 13 Jan 2021 12:45:19 -0800 (PST) Received: by mail-qt1-x849.google.com with SMTP id i1so2448613qtw.4 for ; Wed, 13 Jan 2021 12:45:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:reply-to:date:message-id:mime-version:subject:from:to:cc; bh=dWjn342r4gchACatmFqBw1A1idiYczd8S0EYhHJ6cqk=; b=LXS3/ITVuk/SnWCJkR/nTg4MXjPt/brCtDBIjSa268qeWXDMMq0bw98grRjb4gSo/D Yr7m+C/5PGKWXusNkHcPVMhYTPJ2sVbVQxHIIrTd+Z8qhkUxwX4bVXE9fUD99RjF3+0N wAkNVxSfRvaLMPlhGjhgL56WC+aE1m05Sx4eY9rCgPnxa0ugufDJcyRmcnuxX0uU+nSh wCUVhh/upnrdv9BKmMtFxVLOBjtgz8R1wyGZv/+vk0lP5qNjhPV0PkyJFrM//U25ik6o yORifaOQzbA2M4IcWMXJ9SI7lewXs0MqLMamPwpIiHKY1F8/hf1Jswt0LkM/KOk5qu7t nkRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:reply-to:date:message-id:mime-version :subject:from:to:cc; bh=dWjn342r4gchACatmFqBw1A1idiYczd8S0EYhHJ6cqk=; b=s3v62+g3ebESVfpozJ+4TY7ucnnrrMYzRGX+jyzDB/Ph84diHpRDLs5ZUeC0A/9g2w Mt3Pjuhx+vc6YLCleniFe2xFTxRL/30Z8Z3qi/GvekXbe2ICm4SIZZHwCHxGKSY/HBCJ iePvm2g+8NXgz4GQrSAvAQ+uPZ+taRj5iLKb4rRVn5aCiM7kfhSb/pWwNZEthn7bH/gS mDjKOU2DgJv87AMg5asjOsbBhZHeh1wOmkI9z5cbO1a/zBwukNggFlMHVURp3i5iWeTi a6E/0Hk/a7FRnVFfgkhNUB673rlblx7QedjyJK2C+nneFH8F20rMrK1BoCcgR1T9suae 44gA== X-Gm-Message-State: AOAM533eYs9Gz0JgHiq0/MRKkR+xKKpOjRwasoFjf+Aiqv0QSRSHK3yY G+iKzQP2yh11ZqkORzbA+JNOrYB9t6s= X-Google-Smtp-Source: ABdhPJyF7RbfCRZcwkggVCSN3NJKobLj0tCZ/19NtoaDlqZFS8agG3ajSJPtaiX0BegIC2cNmKIQYvYUP10= Sender: "seanjc via sendgmr" X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:1ea0:b8ff:fe73:50f5]) (user=seanjc job=sendgmr) by 2002:a25:ca4f:: with SMTP id a76mr6085531ybg.140.1610570718745; Wed, 13 Jan 2021 12:45:18 -0800 (PST) Reply-To: Sean Christopherson Date: Wed, 13 Jan 2021 12:45:15 -0800 Message-Id: <20210113204515.3473079-1-seanjc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH] KVM: x86: Add more protection against undefined behavior in rsvd_bits() From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add compile-time asserts in rsvd_bits() to guard against KVM passing in garbage hardcoded values, and cap the upper bound at '63' for dynamic values to prevent generating a mask that would overflow a u64. Suggested-by: Paolo Bonzini Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 581925e476d6..261be1d2032b 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -44,8 +44,15 @@ #define PT32_ROOT_LEVEL 2 #define PT32E_ROOT_LEVEL 3 -static inline u64 rsvd_bits(int s, int e) +static __always_inline u64 rsvd_bits(int s, int e) { + BUILD_BUG_ON(__builtin_constant_p(e) && __builtin_constant_p(s) && e < s); + + if (__builtin_constant_p(e)) + BUILD_BUG_ON(e > 63); + else + e &= 63; + if (e < s) return 0; -- 2.30.0.284.gd98b1dd5eaa7-goog