[PATCH] kernel/module.c: use scnprintf() instead of sprintf()

[PATCH] kernel/module.c: use scnprintf() instead of sprintf()

[Chen Gang]

For some strings, they are permitted to be larger than PAGE_SIZE, so
need use scnprintf() instead of sprintf(), or it will cause issue.

One case is:

  if a module version is crazy defined (length more than PAGE_SIZE),
  'modinfo' command is still OK (print full contents),
  but for "cat /sys/modules/'modname'/version", will cause issue in kernel.


Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
 kernel/module.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 2069158..0618e63 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -603,7 +603,7 @@ static void setup_modinfo_##field(struct module *mod, const char *s)  \
 static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
 			struct module_kobject *mk, char *buffer)      \
 {                                                                     \
-	return sprintf(buffer, "%s\n", mk->mod->field);               \
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
 }                                                                     \
 static int modinfo_##field##_exists(struct module *mod)               \
 {                                                                     \
-- 
1.7.7.6

Re: [PATCH] kernel/module.c: use scnprintf() instead of sprintf()

[Rusty Russell]

Chen Gang <gang.chen@asianux.com> writes:

> For some strings, they are permitted to be larger than PAGE_SIZE, so
> need use scnprintf() instead of sprintf(), or it will cause issue.
>
> One case is:
>
>   if a module version is crazy defined (length more than PAGE_SIZE),
>   'modinfo' command is still OK (print full contents),
>   but for "cat /sys/modules/'modname'/version", will cause issue in kernel.

Applied!

Thanks,
Rusty.

>
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
>  kernel/module.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 2069158..0618e63 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -603,7 +603,7 @@ static void setup_modinfo_##field(struct module *mod, const char *s)  \
>  static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
>  			struct module_kobject *mk, char *buffer)      \
>  {                                                                     \
> -	return sprintf(buffer, "%s\n", mk->mod->field);               \
> +	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
>  }                                                                     \
>  static int modinfo_##field##_exists(struct module *mod)               \
>  {                                                                     \
> -- 
> 1.7.7.6
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
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> Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] kernel/module.c: use scnprintf() instead of sprintf()

[Chen Gang]

On 08/20/2013 02:04 PM, Rusty Russell wrote:
> Chen Gang <gang.chen@asianux.com> writes:
> 
>> For some strings, they are permitted to be larger than PAGE_SIZE, so
>> need use scnprintf() instead of sprintf(), or it will cause issue.
>>
>> One case is:
>>
>>   if a module version is crazy defined (length more than PAGE_SIZE),
>>   'modinfo' command is still OK (print full contents),
>>   but for "cat /sys/modules/'modname'/version", will cause issue in kernel.
> 
> Applied!
> 

Thanks.

> Thanks,
> Rusty.
> 
>>
>> Signed-off-by: Chen Gang <gang.chen@asianux.com>
>> ---
>>  kernel/module.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/kernel/module.c b/kernel/module.c
>> index 2069158..0618e63 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -603,7 +603,7 @@ static void setup_modinfo_##field(struct module *mod, const char *s)  \
>>  static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
>>  			struct module_kobject *mk, char *buffer)      \
>>  {                                                                     \
>> -	return sprintf(buffer, "%s\n", mk->mod->field);               \
>> +	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
>>  }                                                                     \
>>  static int modinfo_##field##_exists(struct module *mod)               \
>>  {                                                                     \
>> -- 
>> 1.7.7.6
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
> 
> 


-- 
Chen Gang