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
Sandbox2 is a C++ security sandbox for Linux which can be used to run untrusted
programs or portions of programs in confined environments. The idea is that the
runtime environment is so restricted that security bugs such as buffer overflows
in the protected region cause no harm.
Documentation
Detailed developer documentation is available on the Google Developers site for Sandboxed API under
Sandbox2.
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