On Thu, Sep 21, 2023 at 03:51:04AM +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.
>
> We expect adap->name to be NUL-terminated based on i2c_adapter name use:
> | dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
>
> NUL-padding does not seem to be required as `master` is zero-allocated
> and `i3c_master_to_i2c_adapter` simply returns a field from within
> `master`:
> | master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
> ...
> | struct i2c_adapter *adap = i3c_master_to_i2c_adapter(master);
> ...
> | static struct i2c_adapter *
> | i3c_master_to_i2c_adapter(struct i3c_master_controller *master)
> | {
> | return &master->i2c;
> | }
>
> This means that `adap->name` should already be filled with NUL-bytes.
>
> Considering the above, 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
Looks right to me; straight replacement.
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
