Allow `keystore` to access the `file` class for `adb_data_file` and `shell_data_file` contexts.
The target contexts correspond to the following locations:
- `adb_data_file`: The library path `/data/adb/modules/tricky_store/libTEESimulator.so`, used for FD transfer.
- `shell_data_file`: The fallback mechanism for loading the library by staging it in `/data/local/tmp`.
Note: The rule for the `dir` class (directory search) has been removed because the supporting audit logs were lost. The remaining file access logs were observed on a MEIZU 21 Note.
After few tests in various devices, it seems that SELinux context modifications are unnecessary for the injection to work.
We thus remove all related manipulations. Further (partial) reverting of the commit must be justified with SELinux logs:
> adb shell su -c 'cat /proc/kmsg | grep avc'
- Strictly adhere to the System V AMD64 ABI by skipping the 128-byte "Red Zone" before modifying the stack, see page 23 of https://gitlab.com/x86-psABIs/x86-64-ABI/-/jobs/artifacts/master/raw/x86-64-ABI/abi.pdf?job=build for details.
- Added `inject_via_staging` as a fallback strategy:
1. Copies the payload to `/data/local/tmp`.
2. Sets permissions/context (`u:object_r:system_file:s0`).
3. Loads via standard `dlopen`.
4. Immediately unlinks the file for stealth.
- Introduced `RegisterRestorer` RAII class to guarantee original registers are restored even if the injection logic returns early due to error.
