[PATCH] PPC: in celleb_show_cpuinfo() convert strncpy(x, y, sizeof(x)) to strlcpy

[PATCH] PPC: in celleb_show_cpuinfo() convert strncpy(x, y, sizeof(x)) to strlcpy

[Roel Kluin]

This patch was not yet tested. Please confirm it's right.
---
strncpy does not append '\0' if the length of the source string equals
the size parameter, strlcpy does.

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/arch/powerpc/platforms/celleb/setup.c b/arch/powerpc/platforms/celleb/setup.c
index f27ae1e..d70fc53 100644
--- a/arch/powerpc/platforms/celleb/setup.c
+++ b/arch/powerpc/platforms/celleb/setup.c
@@ -81,7 +81,7 @@ static void celleb_show_cpuinfo(struct seq_file *m)
 
 static int __init celleb_machine_type_hack(char *ptr)
 {
-	strncpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
+	strlcpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
 	celleb_machine_type[sizeof(celleb_machine_type)-1] = 0;
 	return 0;
 }

Re: [PATCH] PPC: in celleb_show_cpuinfo() convert strncpy(x, y, sizeof(x)) to strlcpy

[Roel Kluin]

Roel Kluin wrote:
> This patch was not yet tested. Please confirm it's right.

was too quick with the send button. the batch below is probably better
---
strncpy does not append '\0' if the length of the source string equals
the size parameter, strlcpy does.

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/arch/powerpc/platforms/celleb/setup.c b/arch/powerpc/platforms/celleb/setup.c
index f27ae1e..cbe09d9 100644
--- a/arch/powerpc/platforms/celleb/setup.c
+++ b/arch/powerpc/platforms/celleb/setup.c
@@ -81,8 +81,7 @@ static void celleb_show_cpuinfo(struct seq_file *m)
 
 static int __init celleb_machine_type_hack(char *ptr)
 {
-	strncpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
-	celleb_machine_type[sizeof(celleb_machine_type)-1] = 0;
+	strlcpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
 	return 0;
 }
 

Re: [PATCH] PPC: in celleb_show_cpuinfo() convert strncpy(x, y, sizeof(x)) to strlcpy

[Ishizaki Kou]

Roel Kluin <12o3l@tiscali.nl> wrote:
> Roel Kluin wrote:
> > This patch was not yet tested. Please confirm it's right.
> 
> was too quick with the send button. the batch below is probably better
> ---
> strncpy does not append '\0' if the length of the source string equals
> the size parameter, strlcpy does.
> 
> Signed-off-by: Roel Kluin <12o3l@tiscali.nl>

Acked-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>

I tested Roel's 2nd patch and it works good on Celleb.

> ---
> diff --git a/arch/powerpc/platforms/celleb/setup.c b/arch/powerpc/platforms/celleb/setup.c
> index f27ae1e..cbe09d9 100644
> --- a/arch/powerpc/platforms/celleb/setup.c
> +++ b/arch/powerpc/platforms/celleb/setup.c
> @@ -81,8 +81,7 @@ static void celleb_show_cpuinfo(struct seq_file *m)
>  
>  static int __init celleb_machine_type_hack(char *ptr)
>  {
> -	strncpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
> -	celleb_machine_type[sizeof(celleb_machine_type)-1] = 0;
> +	strlcpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
>  	return 0;
>  }
>  
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev

Re: [PATCH] PPC: in celleb_show_cpuinfo() convert strncpy(x, y, sizeof(x)) to strlcpy

[Segher Boessenkool]

> This patch was not yet tested. Please confirm it's right.
> ---
> strncpy does not append '\0' if the length of the source string equals
> the size parameter, strlcpy does.

strlcpy() doesn't fill the rest of the array with zeroes, strncpy()
does.  This could matter (information leak, for example), although
I doubt it does here.

> -	strncpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
> +	strlcpy(celleb_machine_type, ptr, sizeof(celleb_machine_type));
>  	celleb_machine_type[sizeof(celleb_machine_type)-1] = 0;

That last statement makes the strncpy() case always zero-terminated,
so this patch isn't necessary.  Oh, and neither the old nor the new
code handles the case where the string doesn't fit (other than just
cutting it short); is that the wanted behaviour?


Segher