`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: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
drivers/i3c/master.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 87283e4a4607..8573ca507708 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -2309,7 +2309,7 @@ static int i3c_master_i2c_adapter_init(struct i3c_master_controller *master)
adap->dev.parent = master->dev.parent;
adap->owner = master->dev.parent->driver->owner;
adap->algo = &i3c_master_i2c_algo;
- strncpy(adap->name, dev_name(master->dev.parent), sizeof(adap->name));
+ strscpy(adap->name, dev_name(master->dev.parent), sizeof(adap->name));
/* FIXME: Should we allow i3c masters to override these values? */
adap->timeout = 1000;
---
base-commit: 2cf0f715623872823a72e451243bbf555d10d032
change-id: 20230921-strncpy-drivers-i3c-master-c-d9e152a91aca
Best regards,
--
Justin Stitt <[email protected]>
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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
Looks right to me; straight replacement.
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
On Thu, 21 Sep 2023 03:51:04 +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);
>
> [...]
Applied, thanks!
[1/1] i3c: replace deprecated strncpy
commit: fa7726a4d9b91e0a8fb6fbbd819cd20f116f6c21
Best regards,
--
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com