RE: [PATCH 1/4] misc: xilinx_sdfec: Fix a couple small information leaks

[Dragan Cvetic]

Hi Dan,

> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx]
> Sent: Wednesday 21 August 2019 08:06
> To: Derek Kiernan <dkiernan@xxxxxxxxxx>; Dragan Cvetic <draganc@xxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>; Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Michal Simek <michals@xxxxxxxxxx>;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kernel-janitors@xxxxxxxxxxxxxxx
> Subject: [PATCH 1/4] misc: xilinx_sdfec: Fix a couple small information leaks
> 
> These structs have holes in them so we end up disclosing a few bytes of
> uninitialized stack data.
> 
> drivers/misc/xilinx_sdfec.c:305 xsdfec_get_status() warn: check that 'status' doesn't leak information (struct has a hole after 'activity')
> drivers/misc/xilinx_sdfec.c:449 xsdfec_get_turbo() warn: check that 'turbo_params' doesn't leak information (struct has a hole after
> 'scale')
> 
> We need to zero out the holes with memset().
> 
> Fixes: 6bd6a690c2e7 ("misc: xilinx_sdfec: Add stats & status ioctls")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
>  drivers/misc/xilinx_sdfec.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c
> index 912e939dec62..dc1b8b412712 100644
> --- a/drivers/misc/xilinx_sdfec.c
> +++ b/drivers/misc/xilinx_sdfec.c
> @@ -295,6 +295,7 @@ static int xsdfec_get_status(struct xsdfec_dev *xsdfec, void __user *arg)
>  	struct xsdfec_status status;
>  	int err;
> 
> +	memset(&status, 0, sizeof(status));
>  	spin_lock_irqsave(&xsdfec->error_data_lock, xsdfec->flags);
>  	status.state = xsdfec->state;
>  	xsdfec->state_updated = false;
> @@ -440,6 +441,7 @@ static int xsdfec_get_turbo(struct xsdfec_dev *xsdfec, void __user *arg)
>  	if (xsdfec->config.code == XSDFEC_LDPC_CODE)
>  		return -EIO;
> 
> +	memset(&turbo_params, 0, sizeof(turbo_params));
>  	reg_value = xsdfec_regread(xsdfec, XSDFEC_TURBO_ADDR);
> 
>  	turbo_params.scale = (reg_value & XSDFEC_TURBO_SCALE_MASK) >>
> --
> 2.20.1

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

Thanks,
Dragan