Sandboxed API Team 3323ddc129 Permit sandboxee's bpf() to fail
The default policy causes immediate termination of a sandboxee that
calls `bpf`(2).

This does not allow for try-call use of `bpf()` to test for optional
features.

To support such try-call use cases, sandboxes would like to say:

```
  sandbox2::PolicyBuilder builder;
  builder.BlockSyscallWithErrno(__NR_bpf, EPERM);
```

but this doesn't work because the default policy unconditionally treats
`bpf()` as a sandbox violation.

Remove the bpf violation check from the policy if `bpf()` is explicitly
blocked with an errno.

PiperOrigin-RevId: 345239389
Change-Id: I7fcfd3a938c610c8679edf8e1fa0238b32cc9db4
2020-12-02 08:38:32 -08:00
..
2020-12-02 08:38:32 -08:00