RE: [PATCH 3/4] misc: xilinx_sdfec: Prevent a divide by zero in xsdfec_reg0_write()

Dragan Cvetic
2019-08-23T08:23:59Z

Hi Dan,

> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
> Sent: Wednesday 21 August 2019 08:10
> To: Derek Kiernan <dkiernan@xilinx.com>; Dragan Cvetic <draganc@xilinx.com>
> Cc: Arnd Bergmann <arnd@arndb.de>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Michal Simek <michals@xilinx.com>;
> linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; kernel-janitors@vger.kernel.org
> Subject: [PATCH 3/4] misc: xilinx_sdfec: Prevent a divide by zero in xsdfec_reg0_write()
>
> The "psize" value comes from the user so we need to verify that it's
> non-zero before we check if "n % psize" or it will crash.
>
> Fixes: 20ec628e8007 ("misc: xilinx_sdfec: Add ability to configure LDPC")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> The parentheses in this condition are a no-op. They're just confusing.
> Perhaps something else was intended?
>
> drivers/misc/xilinx_sdfec.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c
> index 813b82c59360..3fc53d20abf3 100644
> --- a/drivers/misc/xilinx_sdfec.c
> +++ b/drivers/misc/xilinx_sdfec.c
> @@ -460,7 +460,7 @@ static int xsdfec_reg0_write(struct xsdfec_dev *xsdfec, u32 n, u32 k, u32 psize,
> {
> u32 wdata;
>
> - if (n < XSDFEC_REG0_N_MIN || n > XSDFEC_REG0_N_MAX ||
> + if (n < XSDFEC_REG0_N_MIN || n > XSDFEC_REG0_N_MAX || psize == 0 ||
> (n > XSDFEC_REG0_N_MUL_P * psize) || n <= k || ((n % psize) != 0)) {
> dev_dbg(xsdfec->dev, "N value is not in range");
> return -EINVAL;
> --
> 2.20.1

Reviewed-by: Dragan Cvetic <dragan.cvetic@xilinx.com>

Thanks,
Dragan