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Matt RichardsonandClaude Fable 5.1
613c7e3061
Build slackhq/nebula#1821 ("who is this vpn address?" over a local HTTP+JSON socket) on the command registry, so the lookup is one command on every surface and the socket is one more local API. identity - `identity [-address <vpn addr>[:port]]`: no address reports this node; with one, this node or the peer behind an established tunnel - Certificate fields only: name, vpn addresses, networks, unsafe networks, groups, fingerprint, issuer, validity, cert version; a peer's fingerprint is the one nebula computed when it verified the cert - Port accepted and stripped, 4in6 unmapped, so a RemoteAddr passes straight through - No tunnel is a commands.NotFound; an empty -address is refused - Lighthouse TXT lookup shares the owner and peer lookups, keeps answering with the initiating certificate, and no longer panics without a default cert - Served on ssh and nebula ctl too Info API - Off until `local_api.info.enabled` with `socket` and optional quoted octal `socket_mode` (default "0600"); nothing derived - Serves commands declaring Command.Identity plus help; others 403 naming their surfaces. TestInfoAPISurface pins the set to identity - GET /v1 is the schema; GET /v1/<cmd>?<flag>=<value> runs one; body is the -json rendering via commands.Render; commands.PresentationFormat reads json/pretty from the query the way a line is read - 400 commands.ParamError, 403 commands.WithheldError (what Resolve now returns for a withheld name, so help and dispatch type-check it too), 404 NotFound or unknown, 500 Run error, refusal with no reason, or recovered panic with no detail; no redirects; every miss is JSON - listen takes a mode: bind under umask 0077 then chmod; "0660" plus a searchable dir opens it to a group - The chmod, at bind and on a mode-only reload, goes through chmodSocket, which never follows a link: a user who can write the socket's directory could otherwise swap the node for a link and have a root daemon put 0660 or 0666 on any file. Only a socket we own is chmoded. On linux the node is held open O_PATH|O_NOFOLLOW, checked by fstat, and chmoded through /proc/self/fd, so the check and the chmod land on one inode; fchmodat2 is the fallback without /proc. On darwin and the BSDs it is an Lstat check and fchmodat(AT_SYMLINK_NOFOLLOW). clearStale Lstats too, so a dangling link is refused rather than followed by bind on darwin - One endpoint type owns bind under mutex, bind-before-release move, context watch and stop/unlink; each server supplies what it serves - Reloadable through the same reconcile shape as the control socket: mode applied in place, unparsable section keeps what runs, control socket path refused by name - Wire returns Endpoints{Control, Info} with one Stop - Windows unsupported for now (a pipe has no mode); warned once Tests: identity lookups and shapes; API filter, status codes, panic recovery, socket mode, rebind, cancellation; config parsing incl. bare 0660; Wire transitions; e2e of two nebulas with the info API resolving the peer by address and port, through shared test.HTTPDo/HTTPGet helpers. Goldens gain identity. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
46 lines
1.6 KiB
Go
46 lines
1.6 KiB
Go
//go:build darwin || freebsd || netbsd || openbsd
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package localapi
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import (
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"os"
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"golang.org/x/sys/unix"
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)
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// applyAccess sets the owning group and the mode of the socket node at path, and of
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// nothing a link at path names. The node is looked at without following links and must
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// be a socket of ours; the chown and the chmod are fchownat and fchmodat with
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// AT_SYMLINK_NOFOLLOW, which these kernels honour, so a symlink put at path in the one
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// syscall between the look and either call gets its own group or mode changed, which
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// means nothing, and not its target's. A socket cannot be opened, and there is no O_PATH
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// here to hold the inode across the calls the way the linux side does, so a hard link
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// to a file of somebody's choosing swapped in during that one syscall would be changed;
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// that needs the file on the socket's filesystem and the right to link to it, which
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// darwin and the BSDs grant to any user by default.
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func applyAccess(path string, acc Access) error {
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fi, err := os.Lstat(path)
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if err != nil {
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return err
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}
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if err := checkOwnSocket(path, fi); err != nil {
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return err
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}
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// With no group configured the socket is handed back to the daemon's own group, so a
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// reload that drops the key takes the access away; see the linux side.
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gid, err := gidFor(acc)
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if err != nil {
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return err
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}
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if err := unix.Fchownat(unix.AT_FDCWD, path, -1, gid, unix.AT_SYMLINK_NOFOLLOW); err != nil {
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return &os.PathError{Op: "chown", Path: path, Err: err}
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}
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if err := unix.Fchmodat(unix.AT_FDCWD, path, uint32(acc.Mode.Perm()), unix.AT_SYMLINK_NOFOLLOW); err != nil {
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return &os.PathError{Op: "chmod", Path: path, Err: err}
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}
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return nil
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}
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