`strncpy` is deprecated for use on NUL-terminated destination strings [1].
A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on its destination buffer argument which is _not_ always the case for `strncpy`!
In this case, though, there was great care taken to ensure that the destination buffer would be NUL-terminated through the use of `len - 1` ensuring that the previously zero-initialized buffer would not overwrite the last NUL byte. This means that there's no bug here.
However, `strscpy` will add a mandatory NUL byte to the destination buffer as promised by the following `strscpy` implementation [3]: | /* Hit buffer length without finding a NUL; force NUL-termination. */ | if (res) | dest[res-1] = '\0';
This means we can lose the `- 1` which clears up whats happening here. All the while, we get one step closer to eliminating the ambiguous `strncpy` api in favor of its less ambiguous replacement like `strscpy`, `strscpy_pad`, `strtomem` and `strtomem_pad` amongst others.
[1]: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [2]: manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [3]: https://elixir.bootlin.com/linux/v6.3/source/lib/string.c#L183
Link: https://github.com/KSPP/linux/issues/90 Signed-off-by: Justin Stitt justinstitt@google.com --- sound/soc/fsl/fsl_micfil.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/soc/fsl/fsl_micfil.c b/sound/soc/fsl/fsl_micfil.c index 3f08082a55be..fe28b27e50d0 100644 --- a/sound/soc/fsl/fsl_micfil.c +++ b/sound/soc/fsl/fsl_micfil.c @@ -1044,7 +1044,7 @@ static int fsl_micfil_probe(struct platform_device *pdev) return -ENOMEM;
micfil->pdev = pdev; - strncpy(micfil->name, np->name, sizeof(micfil->name) - 1); + strscpy(micfil->name, np->name, sizeof(micfil->name));
micfil->soc = of_device_get_match_data(&pdev->dev);
--- base-commit: 57012c57536f8814dec92e74197ee96c3498d24e change-id: 20230727-sound-soc-fsl-4fc5569d771e
Best regards, -- Justin Stitt justinstitt@google.com