ALSA: xen: ensure nul-terminated device name
diff mbox

Message ID 20180528160011.2989632-1-arnd@arndb.de
State New
Headers show

Commit Message

Arnd Bergmann May 28, 2018, 3:59 p.m. UTC
gcc-8 warns that pcm_instance->name is not necessarily terminated correctly
if the input is more than 80 characters long or lacks a termination byte
itself:

In function 'strncpy',
    inlined from 'cfg_device' at sound/xen/xen_snd_front_cfg.c:399:3,
    inlined from 'xen_snd_front_cfg_card' at sound/xen/xen_snd_front_cfg.c:509:9:
include/linux/string.h:254:9: error: '__builtin_strncpy' specified bound 80 equals destination size [-Werror=stringop-truncation]
  return __builtin_strncpy(p, q, size);

Using strlcpy() instead of strncpy() makes this a bit safer.

Fixes: fd3b36045c2c ("ALSA: xen-front: Read sound driver configuration from Xen store")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 sound/xen/xen_snd_front_cfg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Oleksandr Andrushchenko May 29, 2018, 5:48 a.m. UTC | #1
On 05/28/2018 06:59 PM, Arnd Bergmann wrote:
> gcc-8 warns that pcm_instance->name is not necessarily terminated correctly
> if the input is more than 80 characters long or lacks a termination byte
> itself:
>
> In function 'strncpy',
>      inlined from 'cfg_device' at sound/xen/xen_snd_front_cfg.c:399:3,
>      inlined from 'xen_snd_front_cfg_card' at sound/xen/xen_snd_front_cfg.c:509:9:
> include/linux/string.h:254:9: error: '__builtin_strncpy' specified bound 80 equals destination size [-Werror=stringop-truncation]
>    return __builtin_strncpy(p, q, size);
>
> Using strlcpy() instead of strncpy() makes this a bit safer.
>
> Fixes: fd3b36045c2c ("ALSA: xen-front: Read sound driver configuration from Xen store")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   sound/xen/xen_snd_front_cfg.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sound/xen/xen_snd_front_cfg.c b/sound/xen/xen_snd_front_cfg.c
> index 38c7e1eefbb9..684b5f1d51ac 100644
> --- a/sound/xen/xen_snd_front_cfg.c
> +++ b/sound/xen/xen_snd_front_cfg.c
> @@ -396,7 +396,7 @@ static int cfg_device(struct xen_snd_front_info *front_info,
>   
>   	str = xenbus_read(XBT_NIL, device_path, XENSND_FIELD_DEVICE_NAME, NULL);
>   	if (!IS_ERR(str)) {
> -		strncpy(pcm_instance->name, str, sizeof(pcm_instance->name));
> +		strlcpy(pcm_instance->name, str, sizeof(pcm_instance->name));
>   		kfree(str);
>   	}
>   
Thank you for your patch,
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Takashi Iwai May 29, 2018, 6:28 a.m. UTC | #2
On Tue, 29 May 2018 07:48:51 +0200,
Oleksandr Andrushchenko wrote:
> 
> On 05/28/2018 06:59 PM, Arnd Bergmann wrote:
> > gcc-8 warns that pcm_instance->name is not necessarily terminated correctly
> > if the input is more than 80 characters long or lacks a termination byte
> > itself:
> >
> > In function 'strncpy',
> >      inlined from 'cfg_device' at sound/xen/xen_snd_front_cfg.c:399:3,
> >      inlined from 'xen_snd_front_cfg_card' at sound/xen/xen_snd_front_cfg.c:509:9:
> > include/linux/string.h:254:9: error: '__builtin_strncpy' specified bound 80 equals destination size [-Werror=stringop-truncation]
> >    return __builtin_strncpy(p, q, size);
> >
> > Using strlcpy() instead of strncpy() makes this a bit safer.
> >
> > Fixes: fd3b36045c2c ("ALSA: xen-front: Read sound driver configuration from Xen store")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> >   sound/xen/xen_snd_front_cfg.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/sound/xen/xen_snd_front_cfg.c b/sound/xen/xen_snd_front_cfg.c
> > index 38c7e1eefbb9..684b5f1d51ac 100644
> > --- a/sound/xen/xen_snd_front_cfg.c
> > +++ b/sound/xen/xen_snd_front_cfg.c
> > @@ -396,7 +396,7 @@ static int cfg_device(struct xen_snd_front_info *front_info,
> >     	str = xenbus_read(XBT_NIL, device_path,
> > XENSND_FIELD_DEVICE_NAME, NULL);
> >   	if (!IS_ERR(str)) {
> > -		strncpy(pcm_instance->name, str, sizeof(pcm_instance->name));
> > +		strlcpy(pcm_instance->name, str, sizeof(pcm_instance->name));
> >   		kfree(str);
> >   	}
> >   
> Thank you for your patch,
> Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

Applied now.  Thanks.


Takashi

Patch
diff mbox

diff --git a/sound/xen/xen_snd_front_cfg.c b/sound/xen/xen_snd_front_cfg.c
index 38c7e1eefbb9..684b5f1d51ac 100644
--- a/sound/xen/xen_snd_front_cfg.c
+++ b/sound/xen/xen_snd_front_cfg.c
@@ -396,7 +396,7 @@  static int cfg_device(struct xen_snd_front_info *front_info,
 
 	str = xenbus_read(XBT_NIL, device_path, XENSND_FIELD_DEVICE_NAME, NULL);
 	if (!IS_ERR(str)) {
-		strncpy(pcm_instance->name, str, sizeof(pcm_instance->name));
+		strlcpy(pcm_instance->name, str, sizeof(pcm_instance->name));
 		kfree(str);
 	}