Re: [PATCH-for-5.2] util/cutils: Silent Coverity array overrun warning in freq_to_str()

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Patch aiming the 5.2 release.

On Thu, Oct 29, 2020 at 7:55 PM Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> The biggest input value freq_to_str() can accept is UINT64_MAX,
> which is ~18.446 EHz, less than 1000 EHz.
> Add an assertion to help Coverity.
>
> This silents CID 1435957:  Memory - illegal accesses (OVERRUN):
>
> >>> Overrunning array "suffixes" of 7 8-byte elements at element
>     index 7 (byte offset 63) using index "idx" (which evaluates to 7).
>
> Reported-by: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  util/cutils.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/util/cutils.c b/util/cutils.c
> index c395974fab4..69c0ad7f888 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -891,6 +891,7 @@ char *freq_to_str(uint64_t freq_hz)
>      double freq = freq_hz;
>      size_t idx = 0;
>
> +    assert(freq <= UINT64_MAX); /* Max 64-bit value is less than 1000 EHz */
>      while (freq >= 1000.0 && idx < ARRAY_SIZE(suffixes)) {
>          freq /= 1000.0;
>          idx++;
> --
> 2.26.2
>