Description: f2fs: fix to avoid accessing xattr across the boundary
References:
 https://source.android.com/security/bulletin/pixel/2019-09-01
Notes:
 bwh> Apparently introduced in 3.8 when f2fs was added.
Bugs:
upstream: released (5.2-rc1) [2777e654371dd4207a3a7f4fb5fa39550053a080]
5.10-upstream-stable: N/A "Fixed before branch point"
4.19-upstream-stable: released (4.19.53) [ae3787d433f7b87ebf6b916e524c6e280e4e5804]
4.9-upstream-stable: needed
3.16-upstream-stable: ignored "f2fs is not supportable"
sid: released (5.2.6-1)
5.10-bullseye-security: N/A "Fixed before branching point"
4.19-buster-security: released (4.19.67-1)
4.9-stretch-security: ignored "f2fs is not supportable"
3.16-jessie-security: ignored "f2fs is not supportable"