2023-10-09 23:20:04

by Justin Stitt

[permalink] [raw]
Subject: [PATCH] ibmvnic: replace deprecated strncpy with strscpy

`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

NUL-padding is not required as the buffer is already memset to 0:
| memset(adapter->fw_version, 0, 32);

Note that another usage of strscpy exists on the same buffer:
| strscpy((char *)adapter->fw_version, "N/A", sizeof(adapter->fw_version));

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]>
---
Note: build-tested only.
---
drivers/net/ethernet/ibm/ibmvnic.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index cdf5251e5679..ac15dcadf4c1 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -5247,7 +5247,8 @@ static void handle_vpd_rsp(union ibmvnic_crq *crq,
/* copy firmware version string from vpd into adapter */
if ((substr + 3 + fw_level_len) <
(adapter->vpd->buff + adapter->vpd->len)) {
- strncpy((char *)adapter->fw_version, substr + 3, fw_level_len);
+ strscpy(adapter->fw_version, substr + 3,
+ sizeof(adapter->fw_version));
} else {
dev_info(dev, "FW substr extrapolated VPD buff\n");
}

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231009-strncpy-drivers-net-ethernet-ibm-ibmvnic-c-e0900ba19e56

Best regards,
--
Justin Stitt <[email protected]>


2023-10-10 22:51:59

by Kees Cook

[permalink] [raw]
Subject: Re: [PATCH] ibmvnic: replace deprecated strncpy with strscpy

On Mon, Oct 09, 2023 at 11:19:57PM +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.
>
> NUL-padding is not required as the buffer is already memset to 0:
> | memset(adapter->fw_version, 0, 32);
>
> Note that another usage of strscpy exists on the same buffer:
> | strscpy((char *)adapter->fw_version, "N/A", sizeof(adapter->fw_version));
>
> 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]>

Thanks, this looks right to me.

Reviewed-by: Kees Cook <[email protected]>

--
Kees Cook

2023-10-13 09:21:19

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH] ibmvnic: replace deprecated strncpy with strscpy

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <[email protected]>:

On Mon, 09 Oct 2023 23:19:57 +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.
>
> NUL-padding is not required as the buffer is already memset to 0:
> | memset(adapter->fw_version, 0, 32);
>
> [...]

Here is the summary with links:
- ibmvnic: replace deprecated strncpy with strscpy
https://git.kernel.org/netdev/net-next/c/431acee06923

You are awesome, thank you!
--
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