linux-kernel - Re: KASAN: use-after-free Read in do_general

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: <79eb119f-efc3-35b7-1377-9e4c03182ebd@redhat.com>
Date:   Mon, 28 May 2018 13:25:24 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>,
        syzbot <syzbot+a1264132fc103340628f@...kaller.appspotmail.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        KVM list <kvm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@...glegroups.com>
Subject: Re: KASAN: use-after-free Read in do_general_protection

On 26/05/2018 11:29, Dmitry Vyukov wrote:
> KASAN: stack-out-of-bounds Read in do_general_protection
> KASAN: slab-out-of-bounds Read in vmx_vcpu_run
> KASAN: use-after-scope Read in vmx_vcpu_run
> KASAN: stack-out-of-bounds Write in notify_die
> 
> See full info at:
> https://syzkaller.appspot.com/bug?extid=a1264132fc103340628f
> 
> 
> There seems to be 2 problems:
> 
> 1. msr_write_intercepted doing something notoriously bad.

The faulting line is

        msr_bitmap = to_vmx(vcpu)->loaded_vmcs->msr_bitmap;

so I suppose to_vmx(vcpu)->loaded_vmcs is bogus?  That seems like "just"
a corruption of the struct kvm_vcpu, because the loaded_vmcs field is
pointing elsewhere inside the same struct.

Paolo