Description: net/appletalk: fix minor pointer leak to userspace in SIOCFINDIPDDPRT
References:
 http://blog.infosectcbr.com.au/2018/09/linux-kernel-infoleaks.html
 https://lkml.org/lkml/2018/9/27/480
Notes:
Bugs:
upstream: released (4.19-rc5) [9824dfae5741275473a23a7ed5756c7b6efacc9d]
4.19-upstream-stable: N/A "Fixed before branch point"
4.9-upstream-stable: released (4.9.130) [11f734283a987ac26365aefafdd012a3f37e05a3]
3.16-upstream-stable: released (3.16.64) [0c4d7b52773b227211d311858f3c3b56f7c44874]
sid: released (4.18.20-1)
4.9-stretch-security: released (4.9.130-1)
3.16-jessie-security: released (3.16.64-1)