On Thu, Sep 14, 2023 at 11:21:06PM +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 since `buf` is already zero-initialized. > > 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@xxxxxxxxxxxxxxx > Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> > --- > drivers/hwmon/ibmpowernv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwmon/ibmpowernv.c b/drivers/hwmon/ibmpowernv.c > index 594254d6a72d..57d829dbcda6 100644 > --- a/drivers/hwmon/ibmpowernv.c > +++ b/drivers/hwmon/ibmpowernv.c > @@ -234,7 +234,7 @@ static int get_sensor_index_attr(const char *name, u32 *index, char *attr) > if (copy_len >= sizeof(buf)) > return -EINVAL; > > - strncpy(buf, hash_pos + 1, copy_len); > + strscpy(buf, hash_pos + 1, copy_len); This is another case of precise byte copying -- this just needs to be memcpy. Otherwise this truncates the trailing character. Imagine a name input of "fan#2-data". "buf" wants to get "2". copy_len is 1, and strscpy would eat it. :) -Kees > > err = kstrtou32(buf, 10, index); > if (err) > > --- > base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec > change-id: 20230914-strncpy-drivers-hwmon-ibmpowernv-c-80a03f16d93a > > Best regards, > -- > Justin Stitt <justinstitt@xxxxxxxxxx> > -- Kees Cook
