UPSTREAM: mac80211_hwsim: check HWSIM_ATTR_RADIO_NAME length

[ Upstream commit ff4dd73d ]

Unfortunately, the nla policy was defined to have HWSIM_ATTR_RADIO_NAME
as an NLA_STRING, rather than NLA_NUL_STRING, so we can't use it as a
NUL-terminated string in the kernel.

Rather than break the API, kasprintf() the string to a new buffer to
guarantee NUL termination.

Reported-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 3e8c1a04)
Bug: 70214720
Change-Id: Ia69ed70a7768a004fb4198732e2531091ede1aeb
Signed-off-by: Alistair Strachan <astrachan@google.com>