2013-08-20 03:14:11

by Chen Gang

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

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 <[email protected]>
---
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

2013-08-21 01:17:49

by Rusty Russell

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

Chen Gang <[email protected]> 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 <[email protected]>
> ---
> 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 [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/

2013-08-21 02:25:20

by Chen Gang

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

On 08/20/2013 02:04 PM, Rusty Russell wrote:
> Chen Gang <[email protected]> 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 <[email protected]>
>> ---
>> 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 [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
>
>


--
Chen Gang