diff mbox series

ath5k: replace deprecated strncpy with strscpy

Message ID 20231013-strncpy-drivers-net-wireless-ath-ath5k-led-c-v1-1-3acb0b5a21f2@google.com
State New
Headers
Series ath5k: replace deprecated strncpy with strscpy |

Commit Message

Justin Stitt Oct. 13, 2023, 8:53 p.m. UTC 
  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 led->name to be NUL-terminated based on the presence of a
manual NUL-byte assignment.

This NUL-byte assignment was added in Commit daf9669bea30aa22 ("ath5k:
ensure led name is null terminated"). If strscpy() had existed and had
been used back when this code was written then potential bugs and the
need to manually NUL-terminate could have been avoided. Since we now
have the technology, let's use it :)

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. If NUL-padding is required let's opt
for strscpy_pad().

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.

Found with: $ rg "strncpy\("
---
 drivers/net/wireless/ath/ath5k/led.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)


---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231013-strncpy-drivers-net-wireless-ath-ath5k-led-c-12487cee93be

Best regards,
--
Justin Stitt <justinstitt@google.com>

Comments

Jiri Slaby Oct. 16, 2023, 5:59 a.m. UTC | #1 
On 13. 10. 23, 22:53, 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 led->name to be NUL-terminated based on the presence of a
> manual NUL-byte assignment.
> 
> This NUL-byte assignment was added in Commit daf9669bea30aa22 ("ath5k:
> ensure led name is null terminated"). If strscpy() had existed and had
> been used back when this code was written then potential bugs and the
> need to manually NUL-terminate could have been avoided. Since we now
> have the technology, let's use it :)
> 
> 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. If NUL-padding is required let's opt
> for strscpy_pad().
> 
> 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>

LGTM
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Kalle Valo Oct. 18, 2023, 8:31 a.m. UTC | #2 
Justin Stitt <justinstitt@google.com> 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 led->name to be NUL-terminated based on the presence of a
> manual NUL-byte assignment.
> 
> This NUL-byte assignment was added in Commit daf9669bea30aa22 ("ath5k:
> ensure led name is null terminated"). If strscpy() had existed and had
> been used back when this code was written then potential bugs and the
> need to manually NUL-terminate could have been avoided. Since we now
> have the technology, let's use it :)
> 
> 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. If NUL-padding is required let's opt
> for strscpy_pad().
> 
> 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>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Patch applied to ath-next branch of ath.git, thanks.

24709752bfe8 wifi: ath5k: replace deprecated strncpy with strscpy
diff mbox series

Patch

diff --git a/drivers/net/wireless/ath/ath5k/led.c b/drivers/net/wireless/ath/ath5k/led.c
index 33e9928af363..439052984796 100644
--- a/drivers/net/wireless/ath/ath5k/led.c
+++ b/drivers/net/wireless/ath/ath5k/led.c
@@ -131,8 +131,7 @@  ath5k_register_led(struct ath5k_hw *ah, struct ath5k_led *led,
 	int err;
 
 	led->ah = ah;
-	strncpy(led->name, name, sizeof(led->name));
-	led->name[sizeof(led->name)-1] = 0;
+	strscpy(led->name, name, sizeof(led->name));
 	led->led_dev.name = led->name;
 	led->led_dev.default_trigger = trigger;
 	led->led_dev.brightness_set = ath5k_led_brightness_set;