* [PATCH] staging: strncpy issue, need always let NUL terminated string ended by zero.
@ 2013-05-07 12:11 Chen Gang
2013-05-21 11:47 ` Mauro Carvalho Chehab
0 siblings, 1 reply; 4+ messages in thread
From: Chen Gang @ 2013-05-07 12:11 UTC (permalink / raw)
To: Mauro Carvalho Chehab, josephdanielwalter; +Cc: Greg KH, linux-media, devel
For NUL terminated string, need always let it ended by zero.
The 'name' may be copied to user mode ('dvb_fe->ops.info' is 'struct
dvb_frontend_info' which is defined in ./include/uapi/...), and its
length is also known within as102_dvb_register_fe(), so need fully
initialize it (not use strlcpy instead of strncpy).
Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
drivers/staging/media/as102/as102_fe.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/staging/media/as102/as102_fe.c b/drivers/staging/media/as102/as102_fe.c
index 9ce8c9d..b3efec9 100644
--- a/drivers/staging/media/as102/as102_fe.c
+++ b/drivers/staging/media/as102/as102_fe.c
@@ -334,6 +334,7 @@ int as102_dvb_register_fe(struct as102_dev_t *as102_dev,
memcpy(&dvb_fe->ops, &as102_fe_ops, sizeof(struct dvb_frontend_ops));
strncpy(dvb_fe->ops.info.name, as102_dev->name,
sizeof(dvb_fe->ops.info.name));
+ dvb_fe->ops.info.name[sizeof(dvb_fe->ops.info.name) - 1] = '\0';
/* register dvb frontend */
errno = dvb_register_frontend(dvb_adap, dvb_fe);
--
1.7.7.6
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] staging: strncpy issue, need always let NUL terminated string ended by zero.
2013-05-07 12:11 [PATCH] staging: strncpy issue, need always let NUL terminated string ended by zero Chen Gang
@ 2013-05-21 11:47 ` Mauro Carvalho Chehab
2013-05-21 11:53 ` Chen Gang
0 siblings, 1 reply; 4+ messages in thread
From: Mauro Carvalho Chehab @ 2013-05-21 11:47 UTC (permalink / raw)
To: Chen Gang; +Cc: josephdanielwalter, Greg KH, linux-media, devel
Em Tue, 07 May 2013 20:11:08 +0800
Chen Gang <gang.chen@asianux.com> escreveu:
>
> For NUL terminated string, need always let it ended by zero.
>
> The 'name' may be copied to user mode ('dvb_fe->ops.info' is 'struct
> dvb_frontend_info' which is defined in ./include/uapi/...), and its
> length is also known within as102_dvb_register_fe(), so need fully
> initialize it (not use strlcpy instead of strncpy).
>
>
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
> drivers/staging/media/as102/as102_fe.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/staging/media/as102/as102_fe.c b/drivers/staging/media/as102/as102_fe.c
> index 9ce8c9d..b3efec9 100644
> --- a/drivers/staging/media/as102/as102_fe.c
> +++ b/drivers/staging/media/as102/as102_fe.c
> @@ -334,6 +334,7 @@ int as102_dvb_register_fe(struct as102_dev_t *as102_dev,
> memcpy(&dvb_fe->ops, &as102_fe_ops, sizeof(struct dvb_frontend_ops));
> strncpy(dvb_fe->ops.info.name, as102_dev->name,
> sizeof(dvb_fe->ops.info.name));
> + dvb_fe->ops.info.name[sizeof(dvb_fe->ops.info.name) - 1] = '\0';
Instead, the better would be to use strlcpy(), as it warrants that the
copied string will be nul-terminated.
Regards,
Mauro
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] staging: strncpy issue, need always let NUL terminated string ended by zero.
2013-05-21 11:47 ` Mauro Carvalho Chehab
@ 2013-05-21 11:53 ` Chen Gang
2013-06-08 4:35 ` Chen Gang
0 siblings, 1 reply; 4+ messages in thread
From: Chen Gang @ 2013-05-21 11:53 UTC (permalink / raw)
To: Mauro Carvalho Chehab; +Cc: josephdanielwalter, Greg KH, linux-media, devel
On 05/21/2013 07:47 PM, Mauro Carvalho Chehab wrote:
> Em Tue, 07 May 2013 20:11:08 +0800
> Chen Gang <gang.chen@asianux.com> escreveu:
>
>> >
>> > For NUL terminated string, need always let it ended by zero.
>> >
>> > The 'name' may be copied to user mode ('dvb_fe->ops.info' is 'struct
>> > dvb_frontend_info' which is defined in ./include/uapi/...), and its
>> > length is also known within as102_dvb_register_fe(), so need fully
>> > initialize it (not use strlcpy instead of strncpy).
>> >
>> >
>> > Signed-off-by: Chen Gang <gang.chen@asianux.com>
>> > ---
>> > drivers/staging/media/as102/as102_fe.c | 1 +
>> > 1 files changed, 1 insertions(+), 0 deletions(-)
>> >
>> > diff --git a/drivers/staging/media/as102/as102_fe.c b/drivers/staging/media/as102/as102_fe.c
>> > index 9ce8c9d..b3efec9 100644
>> > --- a/drivers/staging/media/as102/as102_fe.c
>> > +++ b/drivers/staging/media/as102/as102_fe.c
>> > @@ -334,6 +334,7 @@ int as102_dvb_register_fe(struct as102_dev_t *as102_dev,
>> > memcpy(&dvb_fe->ops, &as102_fe_ops, sizeof(struct dvb_frontend_ops));
>> > strncpy(dvb_fe->ops.info.name, as102_dev->name,
>> > sizeof(dvb_fe->ops.info.name));
>> > + dvb_fe->ops.info.name[sizeof(dvb_fe->ops.info.name) - 1] = '\0';
> Instead, the better would be to use strlcpy(), as it warrants that the
> copied string will be nul-terminated.
Within this function, we know 'dvb_fe->ops.info' my copy to user mode
(the structure is defined in ./include/uapi/...), and we also known the
full length of the buffer, so better still use strncpy to give a full
initialized, and still be sure of the nul-terminated.
Thanks.
--
Chen Gang
Asianux Corporation
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] staging: strncpy issue, need always let NUL terminated string ended by zero.
2013-05-21 11:53 ` Chen Gang
@ 2013-06-08 4:35 ` Chen Gang
0 siblings, 0 replies; 4+ messages in thread
From: Chen Gang @ 2013-06-08 4:35 UTC (permalink / raw)
To: Mauro Carvalho Chehab; +Cc: josephdanielwalter, Greg KH, linux-media, devel
Hello Maintainers:
Please help check it when you have time.
Thanks.
On 05/21/2013 07:53 PM, Chen Gang wrote:
> On 05/21/2013 07:47 PM, Mauro Carvalho Chehab wrote:
>> Em Tue, 07 May 2013 20:11:08 +0800
>> Chen Gang <gang.chen@asianux.com> escreveu:
>>
>>>>
>>>> For NUL terminated string, need always let it ended by zero.
>>>>
>>>> The 'name' may be copied to user mode ('dvb_fe->ops.info' is 'struct
>>>> dvb_frontend_info' which is defined in ./include/uapi/...), and its
>>>> length is also known within as102_dvb_register_fe(), so need fully
>>>> initialize it (not use strlcpy instead of strncpy).
>>>>
>>>>
>>>> Signed-off-by: Chen Gang <gang.chen@asianux.com>
>>>> ---
>>>> drivers/staging/media/as102/as102_fe.c | 1 +
>>>> 1 files changed, 1 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/drivers/staging/media/as102/as102_fe.c b/drivers/staging/media/as102/as102_fe.c
>>>> index 9ce8c9d..b3efec9 100644
>>>> --- a/drivers/staging/media/as102/as102_fe.c
>>>> +++ b/drivers/staging/media/as102/as102_fe.c
>>>> @@ -334,6 +334,7 @@ int as102_dvb_register_fe(struct as102_dev_t *as102_dev,
>>>> memcpy(&dvb_fe->ops, &as102_fe_ops, sizeof(struct dvb_frontend_ops));
>>>> strncpy(dvb_fe->ops.info.name, as102_dev->name,
>>>> sizeof(dvb_fe->ops.info.name));
>>>> + dvb_fe->ops.info.name[sizeof(dvb_fe->ops.info.name) - 1] = '\0';
>> Instead, the better would be to use strlcpy(), as it warrants that the
>> copied string will be nul-terminated.
>
> Within this function, we know 'dvb_fe->ops.info' my copy to user mode
> (the structure is defined in ./include/uapi/...), and we also known the
> full length of the buffer, so better still use strncpy to give a full
> initialized, and still be sure of the nul-terminated.
>
>
> Thanks.
>
--
Chen Gang
Asianux Corporation
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-06-08 4:36 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2013-05-07 12:11 [PATCH] staging: strncpy issue, need always let NUL terminated string ended by zero Chen Gang
2013-05-21 11:47 ` Mauro Carvalho Chehab
2013-05-21 11:53 ` Chen Gang
2013-06-08 4:35 ` Chen Gang
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