This commit includes two sepolicy changes:
1. change threadnetwork data file to
/data/misc/apexdata/com.android.tethering/threadnetwork
2. use apex_tethering_data_file for files under
/data/misc/apexdata/com.android.tethering
The background is that the Thread daemon (ot_daemon) is merged into the
Tethering mainline module, which means the the Tehtering module now has
code running in both system_server and the standalone unprivileged
ot_daemon process. To prevent ot_daemon from accessing other
apex_system_server_data_file dirs, here use the specific
apex_tethering_data_file for both Tethering and Thread files (A
subdirectory threadnetwork/ will be created for Thread at runtime). This
is similar to apex_art_data_file and apex_virt_data_file.
Note that a file_contexts rule like
```
/data/misc/apexdata/com\.android\.tethering/threadnetwork(/.*)? u:object_r:apex_threadnetwork_data_file:s0
```
won't work because the threadnetwork/ subdir doesn't exist before the
sepolicy rules are evaluated.
Bug: 309932508
Test: manually verified that Thread settings file can be written to
/data/misc/apexdata/com.android.tethering/threadnetwork
Change-Id: I66539865ef388115c8e9b388b43291d8faf1f384
system_server creates an ICMPv6 socket and send it to ot_daemon via ParcelFileDescriptor. ot_daemon will use that socket to send/receive ICMPv6 messages.
Here's how the socket is created in System Server:
int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
Bug: 294486086
Security consultation bug: 296809188
Test: Verified on a cuttlefish
Change-Id: I9d479c9da01187a0e476591f447f7199ecb3a409
