[PATCH] s390/boot: replace strncpy() with strscpy()

[PATCH] s390/boot: replace strncpy() with strscpy()

[Amir Mohammad Jahangirzad]

From: "Amir Mohammad Jahangirzad" <a.jahangirzad@gmail.com>

strncpy() is deprecated for use on NUL-terminated destination strings
as it doesn't guarantee NUL-termination when the source string length
exceeds the destination buffer size. strscpy() is a safer alternative
as it always NUL-terminates the destination and returns the number of
characters copied (excluding the NUL).

Replace strncpy() with strscpy() for copying the bootdebug_filter value,
using sizeof(bootdebug_filter) rather than sizeof()-1 since strscpy()
takes the full buffer size as parameter.


Link: https://github.com/KSPP/linux/issues/90
Signed-off-by: Amir Mohammad Jahangirzad <a.jahangirzad@gmail.com>
---
 arch/s390/boot/ipl_parm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c
index d04e9b89d14a..8b153f7b4112 100644
--- a/arch/s390/boot/ipl_parm.c
+++ b/arch/s390/boot/ipl_parm.c
@@ -309,7 +309,7 @@ void parse_boot_command_line(void)
 		if (!strcmp(param, "bootdebug")) {
 			bootdebug = true;
 			if (val)
-				strncpy(bootdebug_filter, val, sizeof(bootdebug_filter) - 1);
+				strscpy(bootdebug_filter, val, sizeof(bootdebug_filter));
 		}
 		if (!strcmp(param, "quiet"))
 			boot_console_loglevel = CONSOLE_LOGLEVEL_QUIET;
-- 
2.43.0

Re: [PATCH] s390/boot: replace strncpy() with strscpy()

[Heiko Carstens]

On Thu, Apr 03, 2025 at 02:44:34AM +0330, Amir Mohammad Jahangirzad wrote:
> From: "Amir Mohammad Jahangirzad" <a.jahangirzad@gmail.com>
> 
> strncpy() is deprecated for use on NUL-terminated destination strings
> as it doesn't guarantee NUL-termination when the source string length
> exceeds the destination buffer size. strscpy() is a safer alternative
> as it always NUL-terminates the destination and returns the number of
> characters copied (excluding the NUL).
> 
> Replace strncpy() with strscpy() for copying the bootdebug_filter value,
> using sizeof(bootdebug_filter) rather than sizeof()-1 since strscpy()
> takes the full buffer size as parameter.
> 
> 
> Link: https://github.com/KSPP/linux/issues/90
> Signed-off-by: Amir Mohammad Jahangirzad <a.jahangirzad@gmail.com>
> ---
>  arch/s390/boot/ipl_parm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

You could have at least compile tested this before sending.