5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Justin Stitt <justinstitt@xxxxxxxxxx>
[ Upstream commit b0009b8bed98bd5d59449af48781703df261c247 ]
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 bdi->model_name to be NUL-terminated based on its usage with
sysfs_emit and format strings:
val->strval is assigned to bdi->model_name in
bq24190_charger_get_property():
1186 | val->strval = bdi->model_name;
... then in power_supply_sysfs.c we use value.strval with a format string:
311 | ret = sysfs_emit(buf, "%s\n", value.strval);
we assigned value.strval via:
285 | ret = power_supply_get_property(psy, psp, &value);
... which invokes psy->desc->get_property():
1210 | return psy->desc->get_property(psy, psp, val);
with bq24190_charger_get_property():
1320 | static const struct power_supply_desc bq24190_charger_desc = {
...
1325 | .get_property = bq24190_charger_get_property,
Moreover, no NUL-padding is required as bdi is zero-allocated in
bq24190_charger.c:
1798 | bdi = devm_kzalloc(dev, sizeof(*bdi), 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.
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@xxxxxxxxxxxxxxx
Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231020-strncpy-drivers-power-supply-bq24190_charger-c-v1-1-e896223cb795@xxxxxxxxxx
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/power/supply/bq24190_charger.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c
index 90ac5e59a5d6f..8a4729ee1ab19 100644
--- a/drivers/power/supply/bq24190_charger.c
+++ b/drivers/power/supply/bq24190_charger.c
@@ -1727,7 +1727,7 @@ static int bq24190_probe(struct i2c_client *client,
bdi->client = client;
bdi->dev = dev;
- strncpy(bdi->model_name, id->name, I2C_NAME_SIZE);
+ strscpy(bdi->model_name, id->name, sizeof(bdi->model_name));
mutex_init(&bdi->f_reg_lock);
bdi->f_reg = 0;
bdi->ss_reg = BQ24190_REG_SS_VBUS_STAT_MASK; /* impossible state */
--
2.43.0
