| Message ID | 20230914-strncpy-drivers-hwmon-acpi_power_meter-c-v1-1-905297479fe8@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | hwmon: refactor deprecated strncpy | expand |
On Thu, Sep 14, 2023 at 10:50:15PM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > A suitable replacement is `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 [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> > --- > drivers/hwmon/acpi_power_meter.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c > index fa28d447f0df..9bafe7c85ff7 100644 > --- a/drivers/hwmon/acpi_power_meter.c > +++ b/drivers/hwmon/acpi_power_meter.c > @@ -803,7 +803,7 @@ static int read_capabilities(struct acpi_power_meter_resource *resource) > goto error; > } > > - strncpy(*str, element->string.pointer, element->string.length); > + strscpy(*str, element->string.pointer, element->string.length); This will truncate the destination by 1 training character. This is better replaced with just memcpy() (all the size information has already been calculated and %NUL termination space made in the kcalloc() above it. -Kees > str++; > } > > > --- > base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec > change-id: 20230914-strncpy-drivers-hwmon-acpi_power_meter-c-c9f2d8053bef > > Best regards, > -- > Justin Stitt <justinstitt@google.com> >
diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c index fa28d447f0df..9bafe7c85ff7 100644 --- a/drivers/hwmon/acpi_power_meter.c +++ b/drivers/hwmon/acpi_power_meter.c @@ -803,7 +803,7 @@ static int read_capabilities(struct acpi_power_meter_resource *resource) goto error; } - strncpy(*str, element->string.pointer, element->string.length); + strscpy(*str, element->string.pointer, element->string.length); str++; }
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. We should prefer more robust and less ambiguous string interfaces. A suitable replacement is `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 [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- drivers/hwmon/acpi_power_meter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230914-strncpy-drivers-hwmon-acpi_power_meter-c-c9f2d8053bef Best regards, -- Justin Stitt <justinstitt@google.com>