Messages in this thread | | | From | Arnd Bergmann <> | Date | Tue, 19 Mar 2019 14:05:43 +0100 | Subject | Re: [PATCH 08/12] misc: xilinx_sdfec: Add ability to get/set config |
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On Tue, Mar 19, 2019 at 1:06 PM Dragan Cvetic <dragan.cvetic@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:
> +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.
> 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 *'.
> + */ > +#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 *',
Arnd
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