diff mbox

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

Message ID 9f87aed932fc551c6f5c474b39d01fb337237a7e.1322214950.git.ralf@linux-mips.org
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Ralf Baechle Nov. 25, 2011, 9:09 a.m. UTC 
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 <ralf@linux-mips.org>
Cc: Thomas Osterried <thomas@osterried.de>
---
 net/netrom/nr_route.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

Comments

Walter Harms Nov. 25, 2011, 11:22 a.m. UTC | #1 
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 <ralf@linux-mips.org>
> Cc: Thomas Osterried <thomas@osterried.de>
> ---
>  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];
  };
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Walter Harms Nov. 25, 2011, 12:12 p.m. UTC | #2 
hi,
according to LXR there are several places where the check is >AX25_MAX_DIGIS instead of >=.

any takers ?

re,
 wh


Am 25.11.2011 12:22, schrieb walter harms:
> 
> 
> 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 <ralf@linux-mips.org>
>> Cc: Thomas Osterried <thomas@osterried.de>
>> ---
>>  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];
>   };
> --
> To unsubscribe from this list: send the line "unsubscribe linux-hams" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
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Thomas Osterried Nov. 25, 2011, 1:26 p.m. UTC | #3 
Am Freitag, den 25. November 2011 um 13:12:25 Uhr, schrieb walter harms <wharms@bfs.de> in <4ECF8629.7000301@bfs.de>:
> hi,
> according to LXR there are several places where the check is >AX25_MAX_DIGIS instead of >=.
> 
> any takers ?


nr_route.ndigis is used at 
  nr_call_to_digi(&digi, nr_route.ndigis, nr_route.digipeaters),

Image nr_route.ndigis is 0.

static ax25_digi *nr_call_to_digi(ax25_digi *digi, int ndigis,
        ax25_address *digipeaters)
{
        int i;

        if (ndigis == 0)
                return NULL;

           ################ here we leave

        for (i = 0; i < ndigis; i++) {
                digi->calls[i]    = digipeaters[i];
                digi->repeated[i] = 0;
        }

        digi->ndigi      = ndigis;
        digi->lastrepeat = -1;

        return digi;
}


Image ndigi is 8 (AX25_MAX_DIGIS), as large as nr_route.digipeaters (because it's digipeaters[AX25_MAX_DIGIS]).

we fill the array from i = 0 to i < ndigis (=7) -> 8 times == sizeof(digipeaters)

-> everything is fine with that.

vy 73,
	- Thomas  dl9sau

> 
> re,
>  wh
> 
> 
> Am 25.11.2011 12:22, schrieb walter harms:
> > 
> > 
> > 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 <ralf@linux-mips.org>
> >> Cc: Thomas Osterried <thomas@osterried.de>
> >> ---
> >>  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];
> >   };
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-hams" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> 
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David Miller Nov. 29, 2011, 6:18 a.m. UTC | #4 
From: Ralf Baechle <ralf@linux-mips.org>
Date: Fri, 25 Nov 2011 09:09:00 +0000

> 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 <ralf@linux-mips.org>

Applied.
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diff mbox

Patch

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) {