linux/drivers/power
Justin Stitt 056a75599f power: supply: bq256xx: replace deprecated strncpy with strscpy
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

We expect bq->model_name to be NUL-terminated based on its usage with
sysfs_emit and format strings:

val->strval is assigned to bq->model_name in
bq256xx_get_charger_property():
|       val->strval = bq->model_name;

... then in power_supply_sysfs.c we use value.strval with a format string:
|       ret = sysfs_emit(buf, "%s\n", value.strval);

we assigned value.strval via:
|       ret = power_supply_get_property(psy, psp, &value);
... which invokes psy->desc->get_property():
|       return psy->desc->get_property(psy, psp, val);

with bq256xx_get_charger_property():
|       static const struct power_supply_desc bq256xx_power_supply_desc = {
...
|       	.get_property = bq256xx_get_charger_property,

Moreover, no NUL-padding is required as bq is zero-allocated in
bq256xx_charger.c:
|       bq = devm_kzalloc(dev, sizeof(*bq), GFP_KERNEL);

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.

Let's also opt to use the more idiomatic strscpy() usage of (dest, src,
sizeof(dest)) as this more closely ties the destination buffer and the
length.

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
Similar-to: https://lore.kernel.org/all/20231020-strncpy-drivers-power-supply-bq24190_charger-c-v1-1-e896223cb795@google.com/
Similar-to: https://lore.kernel.org/all/20231020-strncpy-drivers-power-supply-bq2515x_charger-c-v1-1-46664c6edf78@google.com/
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20231020-strncpy-drivers-power-supply-bq256xx_charger-c-v1-1-2fad856124f9@google.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2023-10-21 00:28:13 +02:00
..
reset power: reset: brcmstb: Depend on actual SoC dependencies 2023-10-13 02:33:00 +02:00
supply power: supply: bq256xx: replace deprecated strncpy with strscpy 2023-10-21 00:28:13 +02:00
Kconfig PM: AVS: Drop the avs directory and the corresponding Kconfig 2020-10-22 18:39:32 +02:00
Makefile PM: AVS: Drop the avs directory and the corresponding Kconfig 2020-10-22 18:39:32 +02:00