Re: [PATCH] hw/i386/intel_iommu: Fix out-of-bounds access on guest IRT

[Paolo Bonzini]

On 10/03/20 18:42, Jan Kiszka wrote:
> From: Jan Kiszka <address@hidden>
> 
> vtd_irte_get failed to check the index against the configured table
> size, causing an out-of-bounds access on guest memory and potentially
> misinterpreting the result.
> 
> Signed-off-by: Jan Kiszka <address@hidden>
> ---
> 
> BTW, we still miss error reporting emulation, right? Therefore, I added 
> that simple error_report_once thing, like the other paths do.
> 
>  hw/i386/intel_iommu.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 204b6841ec..df7ad254ac 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -3094,6 +3094,12 @@ static int vtd_irte_get(IntelIOMMUState *iommu, 
> uint16_t index,
>      uint16_t mask, source_id;
>      uint8_t bus, bus_max, bus_min;
>  
> +    if (index >= iommu->intr_size) {
> +        error_report_once("%s: index too large: ind=0x%x",
> +                          __func__, index);
> +        return -VTD_FR_IR_INDEX_OVER;
> +    }
> +
>      addr = iommu->intr_root + index * sizeof(*entry);
>      if (dma_memory_read(&address_space_memory, addr, entry,
>                          sizeof(*entry))) {
> 

Queued, thanks.

Paolo