On Fri, Sep 22, 2023 at 09:25:39AM -0500, Dean Luick wrote:
> On 9/22/2023 5:29 AM, Leon Romanovsky wrote:
> >
> > On Thu, 21 Sep 2023 07:17:47 +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 see that `buf` is expected to be NUL-terminated based on it's use
> >> within a trace event wherein `is_misc_err_name` and `is_various_name`
> >> map to `is_name` through `is_table`:
> >> | TRACE_EVENT(hfi1_interrupt,
> >> | TP_PROTO(struct hfi1_devdata *dd, const struct is_table *is_entry,
> >> | int src),
> >> | TP_ARGS(dd, is_entry, src),
> >> | TP_STRUCT__entry(DD_DEV_ENTRY(dd)
> >> | __array(char, buf, 64)
> >> | __field(int, src)
> >> | ),
> >> | TP_fast_assign(DD_DEV_ASSIGN(dd);
> >> | is_entry->is_name(__entry->buf, 64,
> >> | src - is_entry->start);
> >> | __entry->src = src;
> >> | ),
> >> | TP_printk("[%s] source: %s [%d]", __get_str(dev), __entry->buf,
> >> | __entry->src)
> >> | );
> >>
> >> [...]
> >
> > Applied, thanks!
>
> It is unfortunate that this and the qib patch was accepted so quickly. The
> replacement is functionally correct. However, I was going to suggest using
> strscpy() since the return value is never looked at and all use cases only
> require a NUL-terminated string. Padding is not needed.
Is the trace buffer already guaranteed to be zeroed? Since this is
defined as a fixed-size string in the buffer, it made sense to me to be
sure that the unused bytes were 0 before copying them to userspace.
-Kees
>
> >
> > [1/1] IB/hfi1: replace deprecated strncpy
> > https://git.kernel.org/rdma/rdma/c/c2d0c5b28a77d5
> >
> > Best regards,
>
> External recipient
--
Kees Cook
