thermal: intel: int340x_thermal: replace deprecated strncpy() with strscpy()

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

psvt->limit.string can only be 8 bytes so let's use the appropriate size
macro ACPI_LIMIT_STR_MAX_LEN.

Neither psvt->limit.string or psvt_user[i].limit.string requires the
NUL-padding behavior that strncpy() provides as they have both been
filled with NUL-bytes prior to the string operation.
|	memset(&psvt->limit, 0, sizeof(u64));
and
| 	psvt_user = kzalloc(psvt_len, GFP_KERNEL);

Let's use `strscpy` [2] due to the fact that it guarantees
NUL-termination on the destination buffer without unnecessarily
NUL-padding.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/thermal/intel/int340x_thermal/acpi_thermal_rel.c b/drivers/thermal/intel/int340x_thermal/acpi_thermal_rel.c
index dc519a665c1854a143c85ca636ee10291ac52313..4b4a4d63e61fe5b21785b239afaa511caedb0caa 100644 (file)
--- a/drivers/thermal/intel/int340x_thermal/acpi_thermal_rel.c
+++ b/drivers/thermal/intel/int340x_thermal/acpi_thermal_rel.c
@@ -309,7 +309,7 @@ static int acpi_parse_psvt(acpi_handle handle, int *psvt_count, struct psvt **ps
 
                if (knob->type == ACPI_TYPE_STRING) {
                        memset(&psvt->limit, 0, sizeof(u64));
-                       strncpy(psvt->limit.string, psvt_ptr->limit.str_ptr, knob->string.length);
+                       strscpy(psvt->limit.string, psvt_ptr->limit.str_ptr, ACPI_LIMIT_STR_MAX_LEN);
                } else {
                        psvt->limit.integer = psvt_ptr->limit.integer;
                }
@@ -468,7 +468,7 @@ static int fill_psvt(char __user *ubuf)
                psvt_user[i].unlimit_coeff = psvts[i].unlimit_coeff;
                psvt_user[i].control_knob_type = psvts[i].control_knob_type;
                if (psvt_user[i].control_knob_type == ACPI_TYPE_STRING)
-                       strncpy(psvt_user[i].limit.string, psvts[i].limit.string,
+                       strscpy(psvt_user[i].limit.string, psvts[i].limit.string,
                                ACPI_LIMIT_STR_MAX_LEN);
                else
                        psvt_user[i].limit.integer = psvts[i].limit.integer;