On 12. Feb 2025, at 23:22, Thorsten Blum wrote:
> strncpy() is deprecated for NUL-terminated destination buffers [1]. Use
> strscpy() instead and remove the manual NUL-termination.
>
> Use min() to simplify the size calculation.
>
> Compile-tested only.
>
> Link:
> https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
> [1]
> Cc: [email protected]
> Signed-off-by: Thorsten Blum <[email protected]>
> Suggested-by: Bart Van Assche <[email protected]>
> ---
> drivers/scsi/hpsa.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> index 84d8de07b7ae..9399e101f150 100644
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -460,9 +460,8 @@ static ssize_t host_store_hp_ssd_smart_path_status(struct
> device *dev,
>
> if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
> return -EACCES;
> - len = count > sizeof(tmpbuf) - 1 ? sizeof(tmpbuf) - 1 : count;
> - strncpy(tmpbuf, buf, len);
> - tmpbuf[len] = '\0';
> + len = min(count, sizeof(tmpbuf) - 1);
> + strscpy(tmpbuf, buf, len);
With strscpy() it should probably just be sizeof(tmpbuf) without -1, and
then add +1 to count for the number of copied bytes to be the same as
with strncpy().
Like this:
len = min(count + 1, sizeof(tmpbuf));
This subtle difference between strncpy() and strscpy() regarding the
number of bytes copied isn't really documented anywhere, is it? The
documentation I came across so far seems to focus mostly on the
different return values of the two functions.
> if (sscanf(tmpbuf, "%d", &status) != 1)
> return -EINVAL;
> h = shost_to_hba(shost);
> @@ -484,9 +483,8 @@ static ssize_t host_store_raid_offload_debug(struct
> device *dev,
>
> if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
> return -EACCES;
> - len = count > sizeof(tmpbuf) - 1 ? sizeof(tmpbuf) - 1 : count;
> - strncpy(tmpbuf, buf, len);
> - tmpbuf[len] = '\0';
> + len = min(count, sizeof(tmpbuf) - 1);
> + strscpy(tmpbuf, buf, len);
Same here.
> if (sscanf(tmpbuf, "%d", &debug_level) != 1)
> return -EINVAL;
> if (debug_level < 0)
Maybe someone can confirm my reasoning before I submit a v2?
Thanks,
Thorsten
