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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 2CEDDC10F14 for ; Thu, 10 Oct 2019 08:38:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0703B21920 for ; Thu, 10 Oct 2019 08:38:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570696690; bh=m5bKekGyG+UJ+dgiw3Tg31ttRSjqcr2cZTnp/STQPfA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SbM8KQ18O/Jg4o7KlBOcLN9cH8Brtt90YbahBt9v8yxkU9Iw0O/mBF/GNchS0n7Kj WH69AAuq2awKgvYOVmWOvarh9rkq2My2I+lEXyZlqnWX/c8a5cCtyXx2ptsl70jDXi 3o/sg3Zqi7a/8DYTRuKi9nAWN9lPmbmMDb140MGU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387526AbfJJIiJ (ORCPT ); Thu, 10 Oct 2019 04:38:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:40878 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387519AbfJJIiI (ORCPT ); Thu, 10 Oct 2019 04:38:08 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 52B2520B7C; Thu, 10 Oct 2019 08:38:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570696685; bh=m5bKekGyG+UJ+dgiw3Tg31ttRSjqcr2cZTnp/STQPfA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sD00p9FjVKZSVqeQJgoyP1kuMvVcY0uot8AmINvy1djisEs+Pu86pyM9gXxAe/NsG rso+utBxhmmKbGJILt33hm5KGUtH4+jXRBrBk8zvuicVMF7cR5i7uSliByoZxn1TZd MpO/Y6hlP1mg004VlAf8bWLcW1QAX5JAxvRqU5VE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+0f1819555fbdce992df9@syzkaller.appspotmail.com, Wanpeng Li , Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.3 016/148] KVM: X86: Fix userspace set invalid CR4 Date: Thu, 10 Oct 2019 10:34:37 +0200 Message-Id: <20191010083612.099185303@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191010083609.660878383@linuxfoundation.org> References: <20191010083609.660878383@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Wanpeng Li commit 3ca94192278ca8de169d78c085396c424be123b3 upstream. Reported by syzkaller: WARNING: CPU: 0 PID: 6544 at /home/kernel/data/kvm/arch/x86/kvm//vmx/vmx.c:4689 handle_desc+0x37/0x40 [kvm_intel] CPU: 0 PID: 6544 Comm: a.out Tainted: G OE 5.3.0-rc4+ #4 RIP: 0010:handle_desc+0x37/0x40 [kvm_intel] Call Trace: vmx_handle_exit+0xbe/0x6b0 [kvm_intel] vcpu_enter_guest+0x4dc/0x18d0 [kvm] kvm_arch_vcpu_ioctl_run+0x407/0x660 [kvm] kvm_vcpu_ioctl+0x3ad/0x690 [kvm] do_vfs_ioctl+0xa2/0x690 ksys_ioctl+0x6d/0x80 __x64_sys_ioctl+0x1a/0x20 do_syscall_64+0x74/0x720 entry_SYSCALL_64_after_hwframe+0x49/0xbe When CR4.UMIP is set, guest should have UMIP cpuid flag. Current kvm set_sregs function doesn't have such check when userspace inputs sregs values. SECONDARY_EXEC_DESC is enabled on writes to CR4.UMIP in vmx_set_cr4 though guest doesn't have UMIP cpuid flag. The testcast triggers handle_desc warning when executing ltr instruction since guest architectural CR4 doesn't set UMIP. This patch fixes it by adding valid CR4 and CPUID combination checking in __set_sregs. syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=138efb99600000 Reported-by: syzbot+0f1819555fbdce992df9@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Wanpeng Li Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -884,34 +884,42 @@ int kvm_set_xcr(struct kvm_vcpu *vcpu, u } EXPORT_SYMBOL_GPL(kvm_set_xcr); -int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) +static int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) { - unsigned long old_cr4 = kvm_read_cr4(vcpu); - unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE | - X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE; - if (cr4 & CR4_RESERVED_BITS) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) && (cr4 & X86_CR4_OSXSAVE)) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_SMEP) && (cr4 & X86_CR4_SMEP)) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_SMAP) && (cr4 & X86_CR4_SMAP)) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_FSGSBASE) && (cr4 & X86_CR4_FSGSBASE)) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_PKU) && (cr4 & X86_CR4_PKE)) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_LA57) && (cr4 & X86_CR4_LA57)) - return 1; + return -EINVAL; if (!guest_cpuid_has(vcpu, X86_FEATURE_UMIP) && (cr4 & X86_CR4_UMIP)) + return -EINVAL; + + return 0; +} + +int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) +{ + unsigned long old_cr4 = kvm_read_cr4(vcpu); + unsigned long pdptr_bits = X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PAE | + X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_PKE; + + if (kvm_valid_cr4(vcpu, cr4)) return 1; if (is_long_mode(vcpu)) { @@ -8598,10 +8606,6 @@ EXPORT_SYMBOL_GPL(kvm_task_switch); static int kvm_valid_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs) { - if (!guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) && - (sregs->cr4 & X86_CR4_OSXSAVE)) - return -EINVAL; - if ((sregs->efer & EFER_LME) && (sregs->cr0 & X86_CR0_PG)) { /* * When EFER.LME and CR0.PG are set, the processor is in @@ -8620,7 +8624,7 @@ static int kvm_valid_sregs(struct kvm_vc return -EINVAL; } - return 0; + return kvm_valid_cr4(vcpu, sregs->cr4); } static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)