lkml.org 
[lkml]   [2014]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] s390: net: claw.c: Fix a define larger than in a sizeof in conjunction with strncpy
2014-07-30 10:10 GMT+02:00 Ursula Braun <ubraun@linux.vnet.ibm.com>:
> On Sun, 2014-07-27 at 13:50 +0200, Rickard Strandqvist wrote:
>> The MAX_NAME_LEN is larger than sizeof, which could potentially
>> giving lots of error here.
>>
>> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
>> ---
>> drivers/s390/net/claw.c | 31 +++++++++++++++++++------------
>> 1 file changed, 19 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/s390/net/claw.c b/drivers/s390/net/claw.c
>> index d837c3c..0172ce8 100644
>> --- a/drivers/s390/net/claw.c
>> +++ b/drivers/s390/net/claw.c
>> @@ -3068,12 +3068,15 @@ claw_hname_write(struct device *dev, struct device_attribute *attr,
>> if (!priv)
>> return -ENODEV;
>> p_env = priv->p_env;
>> - if (count > MAX_NAME_LEN+1)
>> + if (count >= sizeof(p_env->host_name) && count > 0)
>> return -EINVAL;
>> - memset(p_env->host_name, 0x20, MAX_NAME_LEN);
>> +
>> strncpy(p_env->host_name,buf, count);
>> - p_env->host_name[count-1] = 0x20; /* clear extra 0x0a */
>> - p_env->host_name[MAX_NAME_LEN] = 0x00;
>> + /* clear extra 0x0a */
>> + memset(&p_env->host_name[count - 1],
>> + ' ', sizeof(p_env->host_name) - count);
>> + p_env->host_name[sizeof(p_env->host_name) - 1] = '\0';
>> +
>> CLAW_DBF_TEXT(2, setup, "HstnSet");
>> CLAW_DBF_TEXT_(2, setup, "%s", p_env->host_name);
>>
>> @@ -3106,12 +3109,14 @@ claw_adname_write(struct device *dev, struct device_attribute *attr,
>> if (!priv)
>> return -ENODEV;
>> p_env = priv->p_env;
>> - if (count > MAX_NAME_LEN+1)
>> + if (count >= sizeof(p_env->adapter_name) && count > 0)
>> return -EINVAL;
>> - memset(p_env->adapter_name, 0x20, MAX_NAME_LEN);
>> +
>> strncpy(p_env->adapter_name,buf, count);
>> - p_env->adapter_name[count-1] = 0x20; /* clear extra 0x0a */
>> - p_env->adapter_name[MAX_NAME_LEN] = 0x00;
>> + /* clear extra 0x0a */
>> + memset(&p_env->adapter_name[count - 1],
>> + ' ', sizeof(p_env->adapter_name) - count);
>> + p_env->adapter_name[sizeof(p_env->adapter_name) - 1] = '\0';
>> CLAW_DBF_TEXT(2, setup, "AdnSet");
>> CLAW_DBF_TEXT_(2, setup, "%s", p_env->adapter_name);
>>
>> @@ -3145,12 +3150,14 @@ claw_apname_write(struct device *dev, struct device_attribute *attr,
>> if (!priv)
>> return -ENODEV;
>> p_env = priv->p_env;
>> - if (count > MAX_NAME_LEN+1)
>> + if (count >= sizeof(p_env->api_type) && count > 0)
>> return -EINVAL;
>> - memset(p_env->api_type, 0x20, MAX_NAME_LEN);
>> +
>> strncpy(p_env->api_type,buf, count);
>> - p_env->api_type[count-1] = 0x20; /* we get a loose 0x0a */
>> - p_env->api_type[MAX_NAME_LEN] = 0x00;
>> + /* we get a loose 0x0a */
>> + memset(&p_env->api_type[count - 1],
>> + ' ', sizeof(p_env->api_type) - count);
>> + p_env->api_type[sizeof(p_env->api_type) - 1] = '\0';
>> if(strncmp(p_env->api_type,WS_APPL_NAME_PACKED,6) == 0) {
>> p_env->read_size=DEF_PACK_BUFSIZE;
>> p_env->write_size=DEF_PACK_BUFSIZE;
>
> Why do you say "MAX_NAME_LEN is larger than sizeof"? MAX_NAME_LEN is 8,
> and claw_env has defined its char arrays as ...[9]?
>

Hi Ursula!

Wondering how I was thinking there. No, no error there.
Possible I assumed that MAX_NAME_LEN it was actually used in the
struct definition, and that was wrong then.
It's something I otherwise think would have been reasonable to do!

And the error I see in the current code is.
It will be wrong if the count == 0 or count == MAX_NAME_LEN + 1 is wrong.

Do not know what you think in general about my patch, or if you want
to keep it more as before.
Otherwise, I have come up with one that is both clearer and better looking...

New patch on the way! :)

Kind regards
Rickard Strandqvist


\
 
 \ /
  Last update: 2014-07-30 22:41    [W:0.050 / U:0.068 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site