ALSA: hda/tegra: refactor deprecated strncpy

`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_ the case for `strncpy`!

It should be noted that the current implementation is unlikely to have a
bug because `drv_name` is a string literal with a size of 9 while
`card->driver` has a size of 16. However, it is probably worthwhile to
switch to a more robust and less ambiguous interface.

[1]: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
[2]: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html

Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20230807-sound-pci-hda-v1-1-6d9cdcd085ca@google.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_tegra.c b/sound/pci/hda/hda_tegra.c
index 39fa036..d967e70 100644 (file)
--- a/sound/pci/hda/hda_tegra.c
+++ b/sound/pci/hda/hda_tegra.c
@@ -379,14 +379,14 @@ static int hda_tegra_first_init(struct azx *chip, struct platform_device *pdev)
        }
 
        /* driver name */
-       strncpy(card->driver, drv_name, sizeof(card->driver));
+       strscpy(card->driver, drv_name, sizeof(card->driver));
        /* shortname for card */
        sname = of_get_property(np, "nvidia,model", NULL);
        if (!sname)
                sname = drv_name;
        if (strlen(sname) > sizeof(card->shortname))
                dev_info(card->dev, "truncating shortname for card\n");
-       strncpy(card->shortname, sname, sizeof(card->shortname));
+       strscpy(card->shortname, sname, sizeof(card->shortname));
 
        /* longname for card */
        snprintf(card->longname, sizeof(card->longname),