`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 can see that linfo->lmac_type is expected to be NUL-terminated based
on the `... - 1`'s present in the current code. Presumably making room
for a NUL-byte at the end of the buffer.
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 prefer the more idiomatic strscpy usage of (dest, src,
sizeof(dest)) rather than (dest, src, SOME_LEN).
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/marvell/octeontx2/af/cgx.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
index e06f77ad6106..6c70c8498690 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
@@ -1218,8 +1218,6 @@ static inline void link_status_user_format(u64 lstat,
struct cgx_link_user_info *linfo,
struct cgx *cgx, u8 lmac_id)
{
- const char *lmac_string;
-
linfo->link_up = FIELD_GET(RESP_LINKSTAT_UP, lstat);
linfo->full_duplex = FIELD_GET(RESP_LINKSTAT_FDUPLEX, lstat);
linfo->speed = cgx_speed_mbps[FIELD_GET(RESP_LINKSTAT_SPEED, lstat)];
@@ -1230,12 +1228,12 @@ static inline void link_status_user_format(u64 lstat,
if (linfo->lmac_type_id >= LMAC_MODE_MAX) {
dev_err(&cgx->pdev->dev, "Unknown lmac_type_id %d reported by firmware on cgx port%d:%d",
linfo->lmac_type_id, cgx->cgx_id, lmac_id);
- strncpy(linfo->lmac_type, "Unknown", LMACTYPE_STR_LEN - 1);
+ strscpy(linfo->lmac_type, "Unknown", sizeof(linfo->lmac_type));
return;
}
- lmac_string = cgx_lmactype_string[linfo->lmac_type_id];
- strncpy(linfo->lmac_type, lmac_string, LMACTYPE_STR_LEN - 1);
+ strscpy(linfo->lmac_type, cgx_lmactype_string[linfo->lmac_type_id],
+ sizeof(linfo->lmac_type));
}
/* Hardware event handlers */
---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231010-strncpy-drivers-net-ethernet-marvell-octeontx2-af-cgx-c-529077646c6a
Best regards,
--
Justin Stitt <[email protected]>
On Tue, Oct 10, 2023 at 09:38:11PM +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 can see that linfo->lmac_type is expected to be NUL-terminated based
> on the `... - 1`'s present in the current code. Presumably making room
> for a NUL-byte at the end of the buffer.
>
> 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 prefer the more idiomatic strscpy usage of (dest, src,
> sizeof(dest)) rather than (dest, src, SOME_LEN).
>
> 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/marvell/octeontx2/af/cgx.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
> index e06f77ad6106..6c70c8498690 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
> @@ -1218,8 +1218,6 @@ static inline void link_status_user_format(u64 lstat,
> struct cgx_link_user_info *linfo,
> struct cgx *cgx, u8 lmac_id)
> {
> - const char *lmac_string;
> -
> linfo->link_up = FIELD_GET(RESP_LINKSTAT_UP, lstat);
> linfo->full_duplex = FIELD_GET(RESP_LINKSTAT_FDUPLEX, lstat);
> linfo->speed = cgx_speed_mbps[FIELD_GET(RESP_LINKSTAT_SPEED, lstat)];
> @@ -1230,12 +1228,12 @@ static inline void link_status_user_format(u64 lstat,
> if (linfo->lmac_type_id >= LMAC_MODE_MAX) {
> dev_err(&cgx->pdev->dev, "Unknown lmac_type_id %d reported by firmware on cgx port%d:%d",
> linfo->lmac_type_id, cgx->cgx_id, lmac_id);
> - strncpy(linfo->lmac_type, "Unknown", LMACTYPE_STR_LEN - 1);
> + strscpy(linfo->lmac_type, "Unknown", sizeof(linfo->lmac_type));
> return;
> }
>
> - lmac_string = cgx_lmactype_string[linfo->lmac_type_id];
> - strncpy(linfo->lmac_type, lmac_string, LMACTYPE_STR_LEN - 1);
> + strscpy(linfo->lmac_type, cgx_lmactype_string[linfo->lmac_type_id],
> + sizeof(linfo->lmac_type));
Yup, sizes match. Good replacement and simplification.
drivers/net/ethernet/marvell/octeontx2/af/mbox.h:565:#define LMACTYPE_STR_LEN 16
drivers/net/ethernet/marvell/octeontx2/af/mbox.h:566: char lmac_type[LMACTYPE_STR_LEN];
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
Hello:
This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <[email protected]>:
On Tue, 10 Oct 2023 21:38:11 +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 can see that linfo->lmac_type is expected to be NUL-terminated based
> on the `... - 1`'s present in the current code. Presumably making room
> for a NUL-byte at the end of the buffer.
>
> [...]
Here is the summary with links:
- octeontx2-af: replace deprecated strncpy with strscpy
https://git.kernel.org/netdev/net-next/c/473f8f2d1bfe
You are awesome, thank you!
--
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