Messages in this thread | | | Date | Sat, 23 Sep 2023 20:04:38 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] i3c: replace deprecated strncpy |
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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: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com>
Looks right to me; straight replacement.
Reviewed-by: Kees Cook <keescook@chromium.org>
-- Kees Cook
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