mwifiex: Fix possible buffer overflows at parsing bss descriptor
mwifiex_update_bss_desc_with_ie() calls memcpy() unconditionally in
a couple places without checking the destination size. Since the
source is given from user-space, this may trigger a heap buffer
overflow.
Fix it by putting the length check before performing memcpy().
This fix addresses CVE-2019-3846.
Reported-by: huangwen <huangwen@venustech.com.cn> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>