Subject: Re: [PATCH 3/4] NET: NETROM: Cleanup argument SIOCADDRT ioctl argument checking.

From: walter harms <[email-masked]>
Date: Fri, 25 Nov 2011 12:22:30 +0100

Am 25.11.2011 10:09, schrieb Ralf Baechle:
> nr_route.ndigis is unsigned int so the nr_route.ndigis < 0 expression is
> never true and can be dropped.  Doing the nr_ax25_dev_get call later
> allows the nr_route.ndigis test to bail out without having to dev_put.
> 
> Signed-off-by: Ralf Baechle <[email-masked]>
> Cc: Thomas Osterried <[email-masked]>
> ---
>  net/netrom/nr_route.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
> index 8d7716c..2cf3301 100644
> --- a/net/netrom/nr_route.c
> +++ b/net/netrom/nr_route.c
> @@ -670,12 +670,10 @@ int nr_rt_ioctl(unsigned int cmd, void __user *arg)
>  	case SIOCADDRT:
>  		if (copy_from_user(&nr_route, arg, sizeof(struct nr_route_struct)))
>  			return -EFAULT;
> -		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
> +		if (nr_route.ndigis > AX25_MAX_DIGIS)
>  			return -EINVAL;
> -		if (nr_route.ndigis < 0 || nr_route.ndigis > AX25_MAX_DIGIS) {
> -			dev_put(dev);
> +		if ((dev = nr_ax25_dev_get(nr_route.device)) == NULL)
>  			return -EINVAL;
> -		}
>  		switch (nr_route.type) {
>  		case NETROM_NODE:
>  			if (strnlen(nr_route.mnemonic, 7) == 7) {

I realy do not know if that matters but some use AX25_MAX_DIGIS as array
and therefore it should be >=AX25_MAX_DIGIS.

struct rose_route_struct {
         rose_address    address;
        unsigned short  mask;
        ax25_address    neighbour;
        char            device[16];
         unsigned char   ndigis;
         ax25_address    digipeaters[AX25_MAX_DIGIS];
  };