[PATCH linux-next] x86/platform/uv: use strscpy to instead of strncpy()

[PATCH linux-next] x86/platform/uv: use strscpy to instead of strncpy()

[yang.yang29]

From: Xu Panda <xu.panda@zte.com.cn>

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.

Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
Signed-off-by: Yang Yang <yang.yang29@zte.com>
---
 arch/x86/platform/uv/uv_nmi.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index a60af0230e27..1b0c8062c731 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -205,8 +205,7 @@ static int param_set_action(const char *val, const struct kernel_param *kp)
 	char arg[ACTION_LEN], *p;

 	/* (remove possible '\n') */
-	strncpy(arg, val, ACTION_LEN - 1);
-	arg[ACTION_LEN - 1] = '\0';
+	strscpy(arg, val, ACTION_LEN - 1);
 	p = strchr(arg, '\n');
 	if (p)
 		*p = '\0';
@@ -959,7 +958,7 @@ static int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)

 		/* Unexpected return, revert action to "dump" */
 		if (master)
-			strncpy(uv_nmi_action, "dump", strlen(uv_nmi_action));
+			strscpy(uv_nmi_action, "dump", strlen(uv_nmi_action));
 	}

 	/* Pause as all CPU's enter the NMI handler */
-- 
2.15.2

Re: [PATCH linux-next] x86/platform/uv: use strscpy to instead of strncpy()

[Andy Shevchenko]

On Sat, Dec 3, 2022 at 8:24 AM <yang.yang29@zte.com.cn> wrote:

> The implementation of strscpy() is more robust and safer.
> That's now the recommended way to copy NUL terminated strings.

...

>         /* (remove possible '\n') */
> -       strncpy(arg, val, ACTION_LEN - 1);
> -       arg[ACTION_LEN - 1] = '\0';
> +       strscpy(arg, val, ACTION_LEN - 1);

Should be ACTION_LEN here, no?

>         p = strchr(arg, '\n');
>         if (p)
>                 *p = '\0';

Wouldn't be better to refactor this

p = strnchrnul(val, ACTION_LEN, '\n');
strscpy(arg, val, p - val);

?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH linux-next] x86/platform/uv: use strscpy to instead of strncpy()

[Andy Shevchenko]

On Sat, Dec 3, 2022 at 2:15 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Sat, Dec 3, 2022 at 8:24 AM <yang.yang29@zte.com.cn> wrote:

...

> >         /* (remove possible '\n') */
> > -       strncpy(arg, val, ACTION_LEN - 1);
> > -       arg[ACTION_LEN - 1] = '\0';
> > +       strscpy(arg, val, ACTION_LEN - 1);
>
> Should be ACTION_LEN here, no?
>
> >         p = strchr(arg, '\n');
> >         if (p)
> >                 *p = '\0';
>
> Wouldn't be better to refactor this
>
> p = strnchrnul(val, ACTION_LEN, '\n');
> strscpy(arg, val, p - val);

Or even drop p completely

strscpy(arg, val, strnchrnul(val, ACTION_LEN, '\n') - val);

-- 
With Best Regards,
Andy Shevchenko