[uml-devel] [PATCH] um,ethertap: use strncpy

2014-08-27 Thread Alan
I can't prove the case pointed out in
https://bugzilla.kernel.org/show_bug.cgi?id=82341
is correct so let us play safe.

Signed-off-by: Alan Cox 
---
 arch/um/os-Linux/drivers/ethertap_user.c |2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/um/os-Linux/drivers/ethertap_user.c 
b/arch/um/os-Linux/drivers/ethertap_user.c
index b39b669..6d49182 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -105,7 +105,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
sprintf(data_fd_buf, "%d", data_remote);
sprintf(version_buf, "%d", UML_NET_VERSION);
if (gate != NULL) {
-   strcpy(gate_buf, gate);
+   strncpy(gate_buf, gate, 15);
args = setup_args;
}
else args = nosetup_args;


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Re: [uml-devel] [PATCH] um,ethertap: use strncpy

2014-08-27 Thread Geert Uytterhoeven
On Wed, Aug 27, 2014 at 5:28 PM, Alan  wrote:
> I can't prove the case pointed out in
> https://bugzilla.kernel.org/show_bug.cgi?id=82341
> is correct so let us play safe.
>
> Signed-off-by: Alan Cox 
> ---
>  arch/um/os-Linux/drivers/ethertap_user.c |2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/um/os-Linux/drivers/ethertap_user.c 
> b/arch/um/os-Linux/drivers/ethertap_user.c
> index b39b669..6d49182 100644
> --- a/arch/um/os-Linux/drivers/ethertap_user.c
> +++ b/arch/um/os-Linux/drivers/ethertap_user.c
> @@ -105,7 +105,7 @@ static int etap_tramp(char *dev, char *gate, int 
> control_me,
> sprintf(data_fd_buf, "%d", data_remote);
> sprintf(version_buf, "%d", UML_NET_VERSION);
> if (gate != NULL) {
> -   strcpy(gate_buf, gate);
> +   strncpy(gate_buf, gate, 15);

This will copy at most 15 bytes.
If "gate" contains 15 or more characters, gate_buf[] won't be
zero-terminated.
I think you better use strlcpy(), unless the remaining of the buffer
must be filled with zeroes.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

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