* [PATCH] cpuidle: dt: refactor deprecated strncpy
@ 2023-09-13 0:23 Justin Stitt
2023-09-15 3:37 ` Kees Cook
2023-09-29 18:45 ` Kees Cook
0 siblings, 2 replies; 3+ messages in thread
From: Justin Stitt @ 2023-09-13 0:23 UTC (permalink / raw)
To: Rafael J. Wysocki, Daniel Lezcano
Cc: linux-pm, linux-kernel, linux-hardening, Justin Stitt
`strncpy` is deprecated for use on NUL-terminated destination strings [1].
We should prefer more robust and less ambiguous string interfaces.
A suitable replacement is `strscpy` [2] due to the fact that it guarantees
NUL-termination on the destination buffer. With this, we can also drop
the now unnecessary `CPUIDLE_(NAME|DESC)_LEN - 1` pieces.
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
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Note: build-tested only
---
drivers/cpuidle/dt_idle_states.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c
index 12fec92a85fd..97feb7d8fb23 100644
--- a/drivers/cpuidle/dt_idle_states.c
+++ b/drivers/cpuidle/dt_idle_states.c
@@ -84,8 +84,8 @@ static int init_state_node(struct cpuidle_state *idle_state,
* replace with kstrdup and pointer assignment when name
* and desc become string pointers
*/
- strncpy(idle_state->name, state_node->name, CPUIDLE_NAME_LEN - 1);
- strncpy(idle_state->desc, desc, CPUIDLE_DESC_LEN - 1);
+ strscpy(idle_state->name, state_node->name, CPUIDLE_NAME_LEN);
+ strscpy(idle_state->desc, desc, CPUIDLE_DESC_LEN);
return 0;
}
---
base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c
change-id: 20230913-strncpy-drivers-cpuidle-dt_idle_states-c-c84ea03c1379
Best regards,
--
Justin Stitt <justinstitt@google.com>
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] cpuidle: dt: refactor deprecated strncpy
2023-09-13 0:23 [PATCH] cpuidle: dt: refactor deprecated strncpy Justin Stitt
@ 2023-09-15 3:37 ` Kees Cook
2023-09-29 18:45 ` Kees Cook
1 sibling, 0 replies; 3+ messages in thread
From: Kees Cook @ 2023-09-15 3:37 UTC (permalink / raw)
To: Justin Stitt
Cc: Rafael J. Wysocki, Daniel Lezcano, linux-pm, linux-kernel,
linux-hardening
On Wed, Sep 13, 2023 at 12:23:19AM +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.
>
> A suitable replacement is `strscpy` [2] due to the fact that it guarantees
> NUL-termination on the destination buffer. With this, we can also drop
> the now unnecessary `CPUIDLE_(NAME|DESC)_LEN - 1` pieces.
>
> 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
> Signed-off-by: Justin Stitt <justinstitt@google.com>
A very regular strncpy/strscpy conversion. :)
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] cpuidle: dt: refactor deprecated strncpy
2023-09-13 0:23 [PATCH] cpuidle: dt: refactor deprecated strncpy Justin Stitt
2023-09-15 3:37 ` Kees Cook
@ 2023-09-29 18:45 ` Kees Cook
1 sibling, 0 replies; 3+ messages in thread
From: Kees Cook @ 2023-09-29 18:45 UTC (permalink / raw)
To: Rafael J. Wysocki, Daniel Lezcano, Justin Stitt
Cc: Kees Cook, linux-pm, linux-kernel, linux-hardening
On Wed, 13 Sep 2023 00:23:19 +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.
>
> A suitable replacement is `strscpy` [2] due to the fact that it guarantees
> NUL-termination on the destination buffer. With this, we can also drop
> the now unnecessary `CPUIDLE_(NAME|DESC)_LEN - 1` pieces.
>
> [...]
Applied to for-next/hardening, thanks!
[1/1] cpuidle: dt: refactor deprecated strncpy
https://git.kernel.org/kees/c/fd94c38f8441
Take care,
--
Kees Cook
^ permalink raw reply [flat|nested] 3+ messages in thread
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