Re: [Qemu-devel] [PATCH v2] ppc/pnv: check size before data buffer access

[Cédric Le Goater]

On 10/26/18 2:33 PM, P J P wrote:
> From: Prasad J Pandit <address@hidden>
> 
> While performing PowerNV memory r/w operations, the access length
> 'sz' could exceed the data[4] buffer size. Add check to avoid OOB
> access.
> 
> Reported-by: Moguofang <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>

Reviewed-by: Cédric Le Goater <address@hidden>

Thanks,

C.


> ---
>  hw/ppc/pnv_lpc.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> Update v2: add error log message
>   -> https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg05750.html
> 
> diff --git a/hw/ppc/pnv_lpc.c b/hw/ppc/pnv_lpc.c
> index d7721320a2..172a915cfc 100644
> --- a/hw/ppc/pnv_lpc.c
> +++ b/hw/ppc/pnv_lpc.c
> @@ -155,9 +155,15 @@ static void pnv_lpc_do_eccb(PnvLpcController *lpc, 
> uint64_t cmd)
>      /* XXX Check for magic bits at the top, addr size etc... */
>      unsigned int sz = (cmd & ECCB_CTL_SZ_MASK) >> ECCB_CTL_SZ_LSH;
>      uint32_t opb_addr = cmd & ECCB_CTL_ADDR_MASK;
> -    uint8_t data[4];
> +    uint8_t data[8];
>      bool success;
>  
> +    if (sz > sizeof(data)) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +            "ECCB: invalid operation at @0x%08x size %d\n", opb_addr, sz);
> +        return;
> +    }
> +
>      if (cmd & ECCB_CTL_READ) {
>          success = opb_read(lpc, opb_addr, data, sz);
>          if (success) {
>