2022-12-03 07:13:21

by Yang Yang

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

From: Xu Panda <[email protected]>

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 <[email protected]>
Signed-off-by: Yang Yang <[email protected]>
---
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

2022-12-03 12:29:32

by Andy Shevchenko

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

On Sat, Dec 3, 2022 at 8:24 AM <[email protected]> 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

2022-12-03 13:25:09

by Andy Shevchenko

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

On Sat, Dec 3, 2022 at 2:15 PM Andy Shevchenko
<[email protected]> wrote:
> On Sat, Dec 3, 2022 at 8:24 AM <[email protected]> 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