`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 know `fw_type` must be NUL-terminated based on use here:
| static bool fw_type_is_auto(void)
| {
| return strncmp(fw_type, LIO_FW_NAME_TYPE_AUTO,
| sizeof(LIO_FW_NAME_TYPE_AUTO)) == 0;
| }
...and here
| module_param_string(fw_type, fw_type, sizeof(fw_type), 0444);
Let's opt to NUL-pad the destination buffer as well so that we maintain
the same exact behavior that `strncpy` provided here.
A suitable replacement is `strscpy_pad` due to the fact that it
guarantees both NUL-termination and NUL-padding on the destination
buffer.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90
Cc: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
Note: build-tested only.
---
drivers/net/ethernet/cavium/liquidio/lio_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 100daadbea2a..34f02a8ec2ca 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -1689,7 +1689,7 @@ static int load_firmware(struct octeon_device *oct)
if (fw_type_is_auto()) {
tmp_fw_type = LIO_FW_NAME_TYPE_NIC;
- strncpy(fw_type, tmp_fw_type, sizeof(fw_type));
+ strscpy_pad(fw_type, tmp_fw_type, sizeof(fw_type));
} else {
tmp_fw_type = fw_type;
}
---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_main-c-b05f78661635
Best regards,
--
Justin Stitt <[email protected]>
On Thu, Oct 05, 2023 at 09:41:01PM +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 know `fw_type` must be NUL-terminated based on use here:
> | static bool fw_type_is_auto(void)
> | {
> | return strncmp(fw_type, LIO_FW_NAME_TYPE_AUTO,
> | sizeof(LIO_FW_NAME_TYPE_AUTO)) == 0;
> | }
> ...and here
> | module_param_string(fw_type, fw_type, sizeof(fw_type), 0444);
>
> Let's opt to NUL-pad the destination buffer as well so that we maintain
> the same exact behavior that `strncpy` provided here.
>
> A suitable replacement is `strscpy_pad` due to the fact that it
> guarantees both NUL-termination and NUL-padding on the destination
> buffer.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
Looks like a safe replacement with strscpy_pad().
Reviewed-by: Kees Cook <[email protected]>
> ---
> Note: build-tested only.
> ---
> drivers/net/ethernet/cavium/liquidio/lio_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
> index 100daadbea2a..34f02a8ec2ca 100644
> --- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
> +++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
> @@ -1689,7 +1689,7 @@ static int load_firmware(struct octeon_device *oct)
>
> if (fw_type_is_auto()) {
> tmp_fw_type = LIO_FW_NAME_TYPE_NIC;
> - strncpy(fw_type, tmp_fw_type, sizeof(fw_type));
> + strscpy_pad(fw_type, tmp_fw_type, sizeof(fw_type));
> } else {
> tmp_fw_type = fw_type;
> }
>
> ---
> base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
> change-id: 20231005-strncpy-drivers-net-ethernet-cavium-liquidio-lio_main-c-b05f78661635
>
> Best regards,
> --
> Justin Stitt <[email protected]>
>
>
--
Kees Cook
Hello:
This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <[email protected]>:
On Thu, 05 Oct 2023 21:41:01 +0000 you 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 know `fw_type` must be NUL-terminated based on use here:
> | static bool fw_type_is_auto(void)
> | {
> | return strncmp(fw_type, LIO_FW_NAME_TYPE_AUTO,
> | sizeof(LIO_FW_NAME_TYPE_AUTO)) == 0;
> | }
> ...and here
> | module_param_string(fw_type, fw_type, sizeof(fw_type), 0444);
>
> [...]
Here is the summary with links:
- net: liquidio: replace deprecated strncpy with strscpy_pad
https://git.kernel.org/netdev/net-next/c/092b0be65032
You are awesome, thank you!
--
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