security: add no-new-privs and seccomp BPF syscall filter#7
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security: add no-new-privs and seccomp BPF syscall filter#7
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## No-New-Privs Set PR_SET_NO_NEW_PRIVS on the spawning OS thread via unix.Prctl before forking each worker. Workers inherit the bit and cannot gain privileges through setuid/setgid binaries (sudo, su, etc.). Enabled by default when sandbox is enabled. sandboxConfig gains a noNewPrivs bool field. ProcessFactory passes noNewPrivs: true in the default sandboxConfig. ## Seccomp BPF filter Add a syscall allowlist filter using github.com/elastic/go-seccomp-bpf (pure Go, no libseccomp dependency). Key properties: - SECCOMP_FILTER_FLAG_TSYNC syncs the filter to all Go runtime threads - Default policy: SeccompPolicyErrno (blocked calls return EPERM) - Explicitly blocks: ptrace, mount, bpf, kexec_load, keyctl, io_uring_*, userfaultfd, perf_event_open, setns, process_vm_* Design: ProcessFactory injects HERD_SECCOMP_PROFILE env var into the worker. Go worker binaries call herd.EnterSandbox() at the top of main() to install the filter. Opaque binaries (ollama, playwright) use WithSeccompPolicy(SeccompPolicyOff) to skip seccomp while still benefiting from cgroup + namespace isolation. New API: - EnterSandbox() error — called by worker binaries at startup - ProcessFactory.WithSeccompPolicy(SeccompPolicy) *ProcessFactory - SeccompPolicy: Off | Log | Errno | Kill New files: - seccomp_linux.go: EnterSandbox, httpWorkerSyscalls allowlist - seccomp_unsupported.go: cross-platform no-op stubs - seccomp_linux_test.go: unit tests for BPF construction and policy Updated examples to use WithSeccompPolicy(SeccompPolicyOff) for opaque binaries (ollama, playwright) with explanatory comments.
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No-New-Privs
Set PR_SET_NO_NEW_PRIVS on the spawning OS thread via unix.Prctl before forking each worker. Workers inherit the bit and cannot gain privileges through setuid/setgid binaries (sudo, su, etc.). Enabled by default when sandbox is enabled.
sandboxConfig gains a noNewPrivs bool field. ProcessFactory passes noNewPrivs: true in the default sandboxConfig.
Seccomp BPF filter
Add a syscall allowlist filter using github.com/elastic/go-seccomp-bpf (pure Go, no libseccomp dependency). Key properties:
Design: ProcessFactory injects HERD_SECCOMP_PROFILE env var into the worker. Go worker binaries call herd.EnterSandbox() at the top of main() to install the filter. Opaque binaries (ollama, playwright) use WithSeccompPolicy(SeccompPolicyOff) to skip seccomp while still benefiting from cgroup + namespace isolation.
New API:
New files:
Updated examples to use WithSeccompPolicy(SeccompPolicyOff) for opaque binaries (ollama, playwright) with explanatory comments.