Re: [patch v2 2/3] staging: speakup: check and convert dev name or ser to dev_t

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sun, Jun 18, 2017 at 09:58:27AM +0100, Okash Khawaja wrote:
> This patch adds functionality to validate and convert either a device
> name or 'ser' member of synth into dev_t. Subsequent patch in this set
> will call it to convert user-specified device into device number. For
> device name, this patch does some basic sanity checks on the string
> passed in. It currently supports ttyS*, ttyUSB* and, for selected
> synths, lp*.
> 
> The patch also introduces a string member variable named 'dev_name' to
> struct spk_synth. 'dev_name' represents the device name - ttyUSB0 etc -
> which needs conversion to dev_t.
> 
> Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
> 
> ---
>  drivers/staging/speakup/spk_priv.h  |    2 +
>  drivers/staging/speakup/spk_ttyio.c |   46 ++++++++++++++++++++++++++++++++++++
>  drivers/staging/speakup/spk_types.h |    1 
>  3 files changed, 49 insertions(+)
> 
> --- a/drivers/staging/speakup/spk_priv.h
> +++ b/drivers/staging/speakup/spk_priv.h
> @@ -40,6 +40,8 @@
>  
>  #define KT_SPKUP 15
>  #define SPK_SYNTH_TIMEOUT 100000 /* in micro-seconds */
> +#define SYNTH_DEFAULT_DEV "ttyS0"
> +#define SYNTH_DEFAULT_SER 0
>  
>  const struct old_serial_port *spk_serial_init(int index);
>  void spk_stop_serial_interrupt(void);
> --- a/drivers/staging/speakup/spk_ttyio.c
> +++ b/drivers/staging/speakup/spk_ttyio.c
> @@ -7,6 +7,10 @@
>  #include "spk_types.h"
>  #include "spk_priv.h"
>  
> +#define DEV_PREFIX_LP "lp"
> +
> +const char *lp_supported[] = { "acntsa", "bns", "dummy", "txprt" };
> +
>  struct spk_ldisc_data {
>  	char buf;
>  	struct semaphore sem;
> @@ -16,6 +20,48 @@ struct spk_ldisc_data {
>  static struct spk_synth *spk_ttyio_synth;
>  static struct tty_struct *speakup_tty;
>  
> +int ser_to_dev(int ser, dev_t *dev_no)
> +{
> +	if (ser < 0 || ser > (255 - 64)) {
> +                pr_err("speakup: Invalid ser param. \
> +				Must be between 0 and 191 inclusive.\n");

As Andy pointed out, never do this for a C string, it's not doing what
you think it is :)

Worse case, do this like the following:
		pr_err("speakup: Invalid ser param."
			"Must be between 0 and 191 inclusive.\n");

Also note, you are using spaces here in the patch, always run
checkpatch.pl on your patches, so you don't get a grumpy maintainer
telling you to run checkpatch.pl on your patches :)

Please fix up and resend the series.

thanks,

greg k-h