librelad 3fe2c0660a feat(peers): direct peer SSH — pairing + peer-shell + pull (Phase 3)
End-to-end direct-ssh-direct: two LibrePortal instances exchange pairing
tokens, each authorizes the other to call a locked-down peer-shell dispatcher
via SSH forced-command, then either side can pull live app data from the
other without needing a shared backup repo.

Push and Connect-via-relay are deferred — push is symmetric to pull (same
forced-command, opposite verb), and the relay variant waits for Connect to
actually exist (config_json + kind enum already future-proofed in Phase 2).

Key generation (peer_key.sh):
  One ed25519 keypair per install at ~<manager>/.ssh/libreportal-peer{,.pub}.
  Generated lazily on the first peer-related call. Used as our outbound
  SSH identity AND as the pubkey other instances authorize.

Forced-command dispatcher (peer_shell.sh):
  Standalone script, deployed by peerInstallShell() to
  ~<manager>/.local/bin/peer-shell. authorized_keys entries look like:
    command="~/.local/bin/peer-shell <peer-name>",no-pty,no-port-forwarding,
    no-X11-forwarding,no-agent-forwarding,no-user-rc ssh-ed25519 AAAA… peer:<name>
  sshd hands us $SSH_ORIGINAL_COMMAND; we parse, whitelist the verb, and
  refuse anything else. Verbs:
    ping        Liveness probe (JSON ok:true).
    list-apps   JSON {peer, apps:[{slug, size_kb}]}.
    stream-app  tar of containers_dir/<slug> to stdout (slug strictly
                validated — lowercase alnum+dash; rejects path traversal).
  Audit log appended to ~/.local/state/libreportal/peer-shell.log. Excluded
  from the generated source arrays (would crash any sourcing shell on empty
  SSH_ORIGINAL_COMMAND); generate_arrays.sh skip-list extended.

Pairing token (peer_pairing.sh):
  Format: lp-peer|v1|<name>|<user>|<host>|<port>|<base64-pubkey>|<fingerprint>
  Pipe-delimited because the SHA256 fingerprint and base64 pubkey both
  contain ':'. peerPairingParse decodes + re-derives the fingerprint from
  the actual key, refusing tokens with mismatched fingerprints (catches
  truncation / tampering). peerPairingAccept:
    1. Installs peer-shell (peerInstallShell).
    2. Appends to authorized_keys with the lockdown options above.
    3. Inserts a peers row (kind=direct-ssh-direct, config carries host,
       port, user, fingerprint).
  Symmetric — user runs accept on BOTH sides with the other's token to
  enable bidirectional calls.

Outbound SSH (peer_remote.sh):
  peerExec <name> <verb> [args] — looks up the peer's connection config and
  ssh's in with the right key, BatchMode + ConnectTimeout + accept-new for
  the host key. peerPing wraps it and updates peers.status + last_seen.

Pull-an-app (peer_pull.sh):
  peerPullApp <peer> <app> [--no-pre-backup] [--keep-urls]
    1. peerPing (refuse if unreachable).
    2. migratePreBackupDestination (reuses the Phase 0 safety wrapper —
       same restic-tagged pre-migrate snapshot as the backup-channel flow).
    3. Stop + wipe destination's app folder.
    4. peerExec stream-app | tar -x (pipefail; bails on partial transfers).
    5. migrateApplyUrlRewrite + dockerComposeUpdateAndStartApp install
       (URL repointing, idempotent install path).
    6. dockerComposeUp + post-restore hooks.
  Identical Stage-2..6 to migrateApplyApp; only the data source differs
  (tar-over-SSH instead of restic-restore).

CLI (cli_peer_commands.sh + header):
  libreportal peer token                — emit this host's pairing token
  libreportal peer pair <token> [name]  — accept a token (override name)
  libreportal peer apps <peer>          — live peer-shell list-apps
  libreportal peer pull <peer> <app> [--no-pre-backup] [--keep-urls]

WebUI (/peers):
  Header gains 'Show my token' and 'Pair with token' buttons (both open
  modals around the matching CLI verbs). Token modal warns the user that
  the token is credentials. Pair modal accepts a free-form override name.
  Direct-SSH peer cards gain a 'List apps' button that opens an inline
  drawer showing the peer's live app inventory (via peer apps) with per-
  app 'Pull' buttons. Pull modal has the same two safety toggles as the
  Migrate tab (pre-backup ON, URL rewrite ON by default).
  Backup-channel manual-add modal kept; direct-SSH must use the token flow.

Smoke-tested:
  - All 16 peer-subsystem functions register without crashing the shell.
  - peer-shell ping ⇒ {ok:true}; unknown-verb refused; path-traversal slug
    refused; valid-slug streams.
  - Token emit→parse round-trip preserves every field; garbage rejected
    with not-a-token; v99 rejected with unsupported-version.
Signed-off-by: librelad <librelad@digitalangels.vip>
2026-05-26 17:56:57 +01:00

56 lines
1.7 KiB
Bash

#!/bin/bash
# Manage the manager-user's peer SSH keypair. One keypair per LibrePortal
# install — used as the *outbound* identity when this host SSHes into a
# direct-ssh peer, AND the public half is what other instances paste into
# their pairing wizard to authorize this host.
#
# Lives under ~/.ssh/libreportal-peer{,.pub} so it sits alongside the other
# manager keys without polluting id_rsa/id_ed25519.
_peerKeyDir() { echo "${HOME}/.ssh"; }
_peerKeyPrivPath() { echo "$(_peerKeyDir)/libreportal-peer"; }
_peerKeyPubPath() { echo "$(_peerKeyDir)/libreportal-peer.pub"; }
# Generate the keypair if it doesn't exist. Idempotent.
peerKeyEnsure()
{
local dir; dir=$(_peerKeyDir)
local priv; priv=$(_peerKeyPrivPath)
local pub; pub=$(_peerKeyPubPath)
if [[ ! -d "$dir" ]]; then
mkdir -p "$dir"
chmod 700 "$dir"
fi
if [[ -f "$priv" && -f "$pub" ]]; then
return 0
fi
isNotice "Generating LibrePortal peer keypair (one-time, ed25519)"
ssh-keygen -t ed25519 -N '' -f "$priv" -C "libreportal-peer@${CFG_INSTALL_NAME:-$(hostname)}" >/dev/null 2>&1
if [[ $? -ne 0 || ! -f "$priv" ]]; then
isError "ssh-keygen failed — peer features unavailable"
return 1
fi
chmod 600 "$priv"
chmod 644 "$pub"
isSuccessful "Peer keypair at $priv"
}
# Echo the local peer pubkey (one line). Empty if not generated yet.
peerKeyPublic()
{
local pub; pub=$(_peerKeyPubPath)
[[ -f "$pub" ]] || return 1
cat "$pub"
}
# Echo the SHA256 fingerprint of the local peer key (matches ssh-keygen -l).
peerKeyFingerprint()
{
local pub; pub=$(_peerKeyPubPath)
[[ -f "$pub" ]] || return 1
ssh-keygen -l -f "$pub" 2>/dev/null | awk '{print $2}'
}