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 ac->name to be NUL-terminated based on its usage with format
strings:
surface_charger.c:
190: ac->psy_desc.name = ac->name;
...
power_supply_core.c:
174: dev_dbg(&psy->dev, "%s: Found supply : %s\n",
175: psy->desc->name, epsy->desc->name);
Moreover, NUL-padding is not required as ac is already zero-allocated
before being passed to spwr_ac_init():
surface_charger.c:
240: ac = devm_kzalloc(&sdev->dev, sizeof(*ac), GFP_KERNEL);
241: if (!ac)
242: return -ENOMEM;
243:
244: spwr_ac_init(ac, sdev, p->registry, p->name);
... this means any future NUL-byte assignments (like the ones that
strncpy() does) are redundant.
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 for the more idiomatic strscpy() usage of:
(dest, src, sizeof(dest))
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]>
---
Note: build-tested only.
Found with: $ rg "strncpy\("
---
drivers/power/supply/surface_charger.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/power/supply/surface_charger.c b/drivers/power/supply/surface_charger.c
index cabdd8da12d0..7a6c62d6f883 100644
--- a/drivers/power/supply/surface_charger.c
+++ b/drivers/power/supply/surface_charger.c
@@ -175,7 +175,7 @@ static void spwr_ac_init(struct spwr_ac_device *ac, struct ssam_device *sdev,
struct ssam_event_registry registry, const char *name)
{
mutex_init(&ac->lock);
- strncpy(ac->name, name, ARRAY_SIZE(ac->name) - 1);
+ strscpy(ac->name, name, sizeof(ac->name));
ac->sdev = sdev;
---
base-commit: bb55d7f7f7445abcc8db50e6a65d4315e79f75c7
change-id: 20231020-strncpy-drivers-power-supply-surface_charger-c-466920fb1f48
Best regards,
--
Justin Stitt <[email protected]>
On Fri, 20 Oct 2023 19:46:11 +0000, Justin Stitt wrote:
> 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 ac->name to be NUL-terminated based on its usage with format
> strings:
>
> [...]
Applied, thanks!
[1/1] power: supply: surface-charger: replace deprecated strncpy with strscpy
commit: afc88dfda013970bb1e214b331e99adca2f98312
Best regards,
--
Sebastian Reichel <[email protected]>
On 10/20/23 21:46, Justin Stitt wrote:
> 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 ac->name to be NUL-terminated based on its usage with format
> strings:
>
> surface_charger.c:
> 190: ac->psy_desc.name = ac->name;
>
> ...
>
> power_supply_core.c:
> 174: dev_dbg(&psy->dev, "%s: Found supply : %s\n",
> 175: psy->desc->name, epsy->desc->name);
>
> Moreover, NUL-padding is not required as ac is already zero-allocated
> before being passed to spwr_ac_init():
>
> surface_charger.c:
> 240: ac = devm_kzalloc(&sdev->dev, sizeof(*ac), GFP_KERNEL);
> 241: if (!ac)
> 242: return -ENOMEM;
> 243:
> 244: spwr_ac_init(ac, sdev, p->registry, p->name);
>
> ... this means any future NUL-byte assignments (like the ones that
> strncpy() does) are redundant.
>
> 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 for the more idiomatic strscpy() usage of:
> (dest, src, sizeof(dest))
>
> 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]>
Thanks!
Reviewed-by: Maximilian Luz <[email protected]>
Tested-by: Maximilian Luz <[email protected]>
> ---
> Note: build-tested only.
>
> Found with: $ rg "strncpy\("
> ---
> drivers/power/supply/surface_charger.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/power/supply/surface_charger.c b/drivers/power/supply/surface_charger.c
> index cabdd8da12d0..7a6c62d6f883 100644
> --- a/drivers/power/supply/surface_charger.c
> +++ b/drivers/power/supply/surface_charger.c
> @@ -175,7 +175,7 @@ static void spwr_ac_init(struct spwr_ac_device *ac, struct ssam_device *sdev,
> struct ssam_event_registry registry, const char *name)
> {
> mutex_init(&ac->lock);
> - strncpy(ac->name, name, ARRAY_SIZE(ac->name) - 1);
> + strscpy(ac->name, name, sizeof(ac->name));
>
> ac->sdev = sdev;
>
>
> ---
> base-commit: bb55d7f7f7445abcc8db50e6a65d4315e79f75c7
> change-id: 20231020-strncpy-drivers-power-supply-surface_charger-c-466920fb1f48
>
> Best regards,
> --
> Justin Stitt <[email protected]>
>