| Message ID | 20230915-strncpy-drivers-hwmon-pmbus-pmbus_core-c-v1-1-fca2cbca41ea@google.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | hwmon: pmbus: refactor deprecated strncpy | expand |
On Fri, Sep 15, 2023 at 06:28:41PM +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. > > `label` is zero-allocated and as such the NUL-padding behavior of > strncpy is not required here. > > 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/pmbus/pmbus_core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c > index 1363d9f89181..dcc8b12387cc 100644 > --- a/drivers/hwmon/pmbus/pmbus_core.c > +++ b/drivers/hwmon/pmbus/pmbus_core.c > @@ -1394,7 +1394,7 @@ static int pmbus_add_label(struct pmbus_data *data, > snprintf(label->name, sizeof(label->name), "%s%d_label", name, seq); > if (!index) { > if (phase == 0xff) > - strncpy(label->label, lstring, > + strscpy(label->label, lstring, > sizeof(label->label) - 1); 'label' is allocated with kzalloc(), and, by copying one byte less than the size of the field into label->label, it is guaranteed to be terminated. Using strscpy() instead of strncpy() results in dropping the last character of lstring if its length is sizeof(label->label) - 1. Really, I am not going to accept any of your patches, sorry. Guenter
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index 1363d9f89181..dcc8b12387cc 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -1394,7 +1394,7 @@ static int pmbus_add_label(struct pmbus_data *data, snprintf(label->name, sizeof(label->name), "%s%d_label", name, seq); if (!index) { if (phase == 0xff) - strncpy(label->label, lstring, + strscpy(label->label, lstring, sizeof(label->label) - 1); else snprintf(label->label, sizeof(label->label), "%s.%d",
`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. `label` is zero-allocated and as such the NUL-padding behavior of strncpy is not required here. 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/pmbus/pmbus_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230915-strncpy-drivers-hwmon-pmbus-pmbus_core-c-8279663960a3 Best regards, -- Justin Stitt <justinstitt@google.com>