Re: [PATCH v2 1/5] MPI: fix off by one in mpi_read_raw_from_sgl

From: Tadeusz Struk
Date: Mon Oct 19 2015 - 19:28:13 EST


On 10/18/2015 03:45 AM, Stephan Mueller wrote:
> The patch fixes the analysis of the input data which contains an off
> by one.
>
> The issue is visible when the SGL contains one byte per SG entry.
> The code for checking for zero bytes does not operate on the data byte.
>
> Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>
> ---
> lib/mpi/mpicoder.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
> index c20ef27..c7e0a70 100644
> --- a/lib/mpi/mpicoder.c
> +++ b/lib/mpi/mpicoder.c
> @@ -446,8 +446,11 @@ MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len)
> const u8 *buff = sg_virt(sg);
> int len = sg->length;
>
> - while (len-- && !*buff++)
> + while (len && !*buff) {
> lzeros++;
> + len--;
> + buff++;
> + }
>
> if (len && *buff)
> break;

ACK. Thanks for testing this Stephan.
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