Re: [PATCH] scsi: elx: sli4: Replace deprecated strncpy() with strscpy()

Kees Cook
2025-04-07T18:28:35Z

On Wed, Feb 26, 2025 at 07:55:26PM +0100, Thorsten Blum wrote:
> strncpy() is deprecated for NUL-terminated destination buffers; use
> strscpy() instead.
>
> Compile-tested only.
>
> Link: https://github.com/KSPP/linux/issues/90
> Cc: linux-hardening@vger.kernel.org
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
> drivers/scsi/elx/libefc_sli/sli4.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/elx/libefc_sli/sli4.c b/drivers/scsi/elx/libefc_sli/sli4.c
> index 5e7fb110bc3f..d9a231fc0e0d 100644
> --- a/drivers/scsi/elx/libefc_sli/sli4.c
> +++ b/drivers/scsi/elx/libefc_sli/sli4.c
> @@ -3804,7 +3804,7 @@ sli_cmd_common_write_object(struct sli4 *sli4, void *buf, u16 noc,
> wr_obj->desired_write_len_dword = cpu_to_le32(dwflags);
>
> wr_obj->write_offset = cpu_to_le32(offset);
> - strncpy(wr_obj->object_name, obj_name, sizeof(wr_obj->object_name) - 1);
> + strscpy(wr_obj->object_name, obj_name);

Standard question for these kinds of conversions: Why is it safe that
this is not NUL padded? I haven't found where this buffer is being
zeroed out, but it probably is (given the "- 1" on the length), but
without run-time testing, this needs much more careful analysis.

-Kees

> wr_obj->host_buffer_descriptor_count = cpu_to_le32(1);
>
> bde = (struct sli4_bde *)wr_obj->host_buffer_descriptor;
> @@ -3833,7 +3833,7 @@ sli_cmd_common_delete_object(struct sli4 *sli4, void *buf, char *obj_name)
> SLI4_SUBSYSTEM_COMMON, CMD_V0,
> SLI4_RQST_PYLD_LEN(cmn_delete_object));
>
> - strncpy(req->object_name, obj_name, sizeof(req->object_name) - 1);
> + strscpy(req->object_name, obj_name);
> return 0;
> }
>
> @@ -3856,7 +3856,7 @@ sli_cmd_common_read_object(struct sli4 *sli4, void *buf, u32 desired_read_len,
> cpu_to_le32(desired_read_len & SLI4_REQ_DESIRE_READLEN);
>
> rd_obj->read_offset = cpu_to_le32(offset);
> - strncpy(rd_obj->object_name, obj_name, sizeof(rd_obj->object_name) - 1);
> + strscpy(rd_obj->object_name, obj_name);
> rd_obj->host_buffer_descriptor_count = cpu_to_le32(1);
>
> bde = (struct sli4_bde *)rd_obj->host_buffer_descriptor;
> --
> 2.48.1
>

--
Kees Cook