On Fri, Aug 11, 2023 at 09:56:15PM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > Use `strscpy_pad` which has the same behavior as `strncpy` here with the > extra safeguard of guaranteeing NUL-termination of destination strings. > In it's current form, this may result in silent truncation if the src > string has the same size as the destination string. > > Link: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings[1] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@xxxxxxxxxxxxxxx > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> > --- > arch/s390/kernel/ipl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c > index 85a00d97a314..a6dcf6f28197 100644 > --- a/arch/s390/kernel/ipl.c > +++ b/arch/s390/kernel/ipl.c > @@ -266,7 +266,7 @@ static ssize_t sys_##_prefix##_##_name##_store(struct kobject *kobj, \ > struct kobj_attribute *attr, \ > const char *buf, size_t len) \ > { \ > - strncpy(_value, buf, sizeof(_value) - 1); \ > + strscpy_pad(_value, buf, sizeof(_value)); \ Padding isn't needed here -- the string are consumed by __cpcmd(), which explicitly uses strlen() and a memcpy to pass them off. > strim(_value); \ This existing code line is buggy, though -- it will not trim leading whitespace in the buffer. (It _returns_ a string that has been forward-adjusted.) I think this is an API mistake -- strim() should either do in-place changes for both ends or be defined with __much_check so the return value doesn't get lost. (But this is a separate issue.) -Kees -- Kees Cook
