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Re: [Qemu-devel] [PATCH v2] ppc/pnv: check size before data buffer acces
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH v2] ppc/pnv: check size before data buffer access |
Date: |
Thu, 8 Nov 2018 10:10:25 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
On 26/10/2018 14:33, 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>
> ---
> 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;
I'm not sure 8 is enough.
ECCB_CTL_SZ_MASK is PPC_BITMASK(4, 7), and ECCB_CTL_SZ_LSH is (63 - 7).
So the bitmask is 4 bits wide, and thus sz can be 0 to 15.
I think data[] size should be 16.
Thanks,
Laurent