POSIX states that the value of endptr is unspecified if strtol()
fails with EINVAL due to an invalid base argument.  Since none of
the callers to check_strtox_error() initialized endptr, we could
end up propagating uninitialized data back to a caller on error.
However, passing an out-of-range base is already a sign of poor
programming, so let's just assert that base is in range, at which
point check_strtox_error() can be tightened to assert that it is
receiving an initialized ep that points somewhere within the
caller's original string, regardless of whether strto*() succeeded
or failed with ERANGE.
Reported-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20181206151856.77503-1-eblake@redhat.com>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>