Thales Maciel
b930c51990
Previously the daemon socket, per-VM firecracker API socket, and vsock socket were transiently world-exposed on hosts without XDG_RUNTIME_DIR: the runtime directory landed in /tmp at 0755, Firecracker ran with umask 000 (mode 0666 sockets), and only a follow-up chown/chmod in EnsureSocketAccess tightened them. A local attacker could race into bangerd.sock or the firecracker API socket during that window. Three changes: - internal/paths/paths.go: RuntimeDir is now created (and re-chmod'd if stale) at 0700 unconditionally. When XDG_RUNTIME_DIR is unset and we fall back to /tmp/banger-runtime-<uid>, Ensure() now verifies the parent dir is owned by the current uid and 0700 mode — refusing to place sockets inside a directory someone else created. Symlink swaps rejected via Lstat. - internal/firecracker/client.go: launch firecracker with umask 077 instead of umask 000 so the API socket is mode 0600 from birth. The chown in fcproc.EnsureSocketAccess still transfers ownership from root to the invoking user afterwards. - internal/daemon/fcproc/fcproc.go: EnsureSocketDir now creates (and re-chmod's) the runtime socket directory at 0700. Tests cover the tightening path — an existing 0755 RuntimeDir is re-chmod'd on Ensure. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> |
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| layout_test.go | ||
| paths.go | ||
| paths_test.go | ||