strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces.
`desc` is expected to be NUL-terminated as evident by the manual NUL-byte assignment. Moreover, NUL-padding does not seem to be necessary. The only caller of efx_mcdi_nvram_metadata() is efx_devlink_info_nvram_partition() which provides a NULL for `desc`: | rc = efx_mcdi_nvram_metadata(efx, partition_type, NULL, version, NULL, 0); Due to this, I am not sure this code is even reached but we should still favor something other than strncpy. 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: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinst...@google.com> --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/ethernet/sfc/mcdi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c index d23da9627338..76578502226e 100644 --- a/drivers/net/ethernet/sfc/mcdi.c +++ b/drivers/net/ethernet/sfc/mcdi.c @@ -2205,10 +2205,9 @@ int efx_mcdi_nvram_metadata(struct efx_nic *efx, unsigned int type, goto out_free; } - strncpy(desc, + strscpy(desc, MCDI_PTR(outbuf, NVRAM_METADATA_OUT_DESCRIPTION), MC_CMD_NVRAM_METADATA_OUT_DESCRIPTION_NUM(outlen)); - desc[MC_CMD_NVRAM_METADATA_OUT_DESCRIPTION_NUM(outlen)] = '\0'; } else { desc[0] = '\0'; } --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231012-strncpy-drivers-net-ethernet-sfc-mcdi-c-cf970a9b7d60 Best regards, -- Justin Stitt <justinst...@google.com>
