lkml.org 
[lkml]   [2017]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH RESEND] KVM: X86: Fix stack-out-of-bounds read in write_mmio
From
Date
On 12/12/2017 09:57, Wanpeng Li wrote:
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index bc5d853..51e7932 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4690,7 +4690,10 @@ static int write_emulate(struct kvm_vcpu *vcpu, gpa_t gpa,
>
> static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val)
> {
> - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val);
> + u64 data = 0;
> +
> + memcpy(&data, val, min(8, bytes));
> + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, data);
> return vcpu_mmio_write(vcpu, gpa, bytes, val);
> }
>
>

Please do the memcpy in TRACE_EVENT(kvm_mmio)'s TP_fast_assign block.
That is done only when the trace event is active.

Thanks,

Paolo

\
 
 \ /
  Last update: 2017-12-12 17:08    [W:0.039 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site