> -----Original Message-----
> From: Arnd Bergmann [mailto:a...@arndb.de]
> Sent: Tuesday 19 March 2019 13:06
> To: Dragan Cvetic <drag...@xilinx.com>
> Cc: gregkh <gre...@linuxfoundation.org>; Michal Simek <mich...@xilinx.com>;
> Linux ARM <linux-arm-ker...@lists.infradead.org>;
> Linux Kernel Mailing List <linux-kernel@vger.kernel.org>; Derek Kiernan
> <dkier...@xilinx.com>
> Subject: Re: [PATCH 08/12] misc: xilinx_sdfec: Add ability to get/set config
>
> On Tue, Mar 19, 2019 at 1:06 PM Dragan Cvetic <dragan.cve...@xilinx.com>
> wrote:
> > - Add capability to get SD-FEC config data using ioctl
> > XSDFEC_GET_CONFIG.
> >
> > - Add capability to set SD-FEC data order using ioctl
> > SDFEC_SET_ORDER. The order of data blocks can change
> > from input to output or to be maintained.
>
> Commenting here only on the ABI, not the actual behavior of the driver:
Will be removed.
>
> > +static int xsdfec_get_config(struct xsdfec_dev *xsdfec, void __user *arg)
> > +{
> > + int err;
> > +
> > + err = copy_to_user(arg, &xsdfec->config, sizeof(xsdfec->config));
> > + if (err) {
> > + dev_err(xsdfec->dev, "%s failed for SDFEC%d", __func__,
> > + xsdfec->config.fec_id);
> > + err = -EFAULT;
> > + }
>
> Try to avoid printing error messages for things that can be triggered from
> user space.
Will be removed.
>
> > static int xsdfec_set_turbo(struct xsdfec_dev *xsdfec, void __user *arg)
> > {
> > struct xsdfec_turbo turbo;
> > @@ -670,6 +683,67 @@ static int xsdfec_add_ldpc(struct xsdfec_dev *xsdfec,
> > void __user *arg)
> > return ret;
> > }
> >
> > +static int xsdfec_set_order(struct xsdfec_dev *xsdfec, void __user *arg)
> > +{
> > + bool order_invalid;
> > + enum xsdfec_order order = *((enum xsdfec_order *)arg);
>
> Generally speaking, you should never cast between __user pointers
> and kernel pointers. It looks like this will actually dereference a
> __user pointer, which is a security issue.
>
> Another problem is that the command is defined as
>
> #define XSDFEC_SET_ORDER _IOW(XSDFEC_MAGIC, 8, unsigned long *)
>
> which would indicate an argument of type 'unsigned long __user * __user *',
> which is incompatible with 'enum xsdfec_order __user *'. Both enum
> and pointer types are variable length and should be avoided in
> ioctl commands. Best make this a '__u64 __user *' or '__u32 __user *'.
Will be updated as proposed.
>
> > + */
> > +#define XSDFEC_GET_CONFIG _IOR(XSDFEC_MAGIC, 6, struct xsdfec_config *)
> > +/**
> > * DOC: XSDFEC_GET_TURBO
> > * @Parameters
> > *
> > @@ -322,4 +335,48 @@ xsdfec_calculate_shared_ldpc_table_entry_size(struct
> > xsdfec_ldpc_params *ldpc,
> > * ioctl that returns SD-FEC turbo param values
> > */
> > #define XSDFEC_GET_TURBO _IOR(XSDFEC_MAGIC, 7, struct xsdfec_turbo *)
>
> Also wrong type, the function takes a 'struct xsdfec_turbo __user *', not a
> 'struct xsdfec_turbo __user * __user *',
Will be updated as proposed
>
> Arnd
Thank you
Dragan
