Re: KMSAN: kernel-infoleak in kvm_vcpu_write_guest_page

2018-11-07 Thread Paolo Bonzini
On 07/11/2018 13:58, Liran Alon wrote: > > >> On 7 Nov 2018, at 14:47, Paolo Bonzini wrote: >> >> On 07/11/2018 13:10, Alexander Potapenko wrote: >>> This appears to be a real bug in KVM. >>> Please see a simplified reproducer attached. >> >> Thanks, I agree it's a reael bug. The basic issue is

Re: KMSAN: kernel-infoleak in kvm_vcpu_write_guest_page

2018-11-07 Thread Liran Alon
> On 7 Nov 2018, at 14:47, Paolo Bonzini wrote: > > On 07/11/2018 13:10, Alexander Potapenko wrote: >> This appears to be a real bug in KVM. >> Please see a simplified reproducer attached. > > Thanks, I agree it's a reael bug. The basic issue is that the > kvm_state->size member is too small

Re: KMSAN: kernel-infoleak in kvm_vcpu_write_guest_page

2018-11-07 Thread Liran Alon
> On 7 Nov 2018, at 14:10, Alexander Potapenko wrote: > > On Wed, Nov 7, 2018 at 2:38 AM syzbot > wrote: >> >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit:88b95ef4c780 kmsan: use MSan assembly instrumentation >> git tree: >> https://urldefense.proofpoint.

Re: KMSAN: kernel-infoleak in kvm_vcpu_write_guest_page

2018-11-07 Thread Paolo Bonzini
On 07/11/2018 13:10, Alexander Potapenko wrote: > This appears to be a real bug in KVM. > Please see a simplified reproducer attached. Thanks, I agree it's a reael bug. The basic issue is that the kvm_state->size member is too small (1040) in the KVM_SET_NESTED_STATE ioctl, aka 0x4080aebf. One w

Re: KMSAN: kernel-infoleak in kvm_vcpu_write_guest_page

2018-11-07 Thread Alexander Potapenko
On Wed, Nov 7, 2018 at 2:38 AM syzbot wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit:88b95ef4c780 kmsan: use MSan assembly instrumentation > git tree: https://github.com/google/kmsan.git/master > console output: https://syzkaller.appspot.com/x/log.txt?x=12505e