Replaces the opaque Bounty.bounty_type='credential' path with a
dedicated `credentials` table whose schema is forward-compatible
across every auth-bearing service in the fleet. Hoisted indexed
columns (secret_sha256, principal, service, attacker_ip) carry the
universal reuse-analytics signal; service-specific JSON keys ride
in `fields`. Cross-service reuse queries become an indexed lookup
on secret_sha256 instead of JSON_EXTRACT scans.
Schema decisions baked in (per ANTI):
- New `Credential` table, not extension to Bounty
- Hoisted `principal` column for cross-service principal-reuse
- Standardized JSON keys: every payload carries secret_b64 +
secret_printable + principal universally; service-specific extras
(user, domain, dn, mech, …) ride alongside
The auth-helper SD-block emits the new shape natively. The ingester
forks at _extract_bounty:
- Native shape (SSH/Telnet, future emitters): secret_b64 present →
direct upsert_credential
- Legacy shape (FTP/POP3/IMAP/SMTP today): username + password →
adapter synthesizes secret_{b64,sha256,printable} on the fly,
upserts into the same Credential table. Tracked as DEBT-039;
one-shot bridge until those service templates migrate.
Defense-in-depth across five layers (input validation):
- C helper: bytes outside [0x20, 0x7f) collapse to '?', RFC 5424
escape rules for \\, ", ]; b64 preserves exact bytes
- Ingester native branch: rejects malformed secret_b64 (regex), drops
the credential row but keeps the underlying Log
- Ingester legacy adapter: same printable-ASCII filter as the C
code; sha256 + b64 over the original utf-8 bytes (lossless, even
when secret_printable is sanitized)
- DB column caps with truncation warning; sha256 always over the
full pre-truncation bytes so reuse queries match across truncation
- JSON serialized with ensure_ascii=True so utf8mb4 columns stay
safe even with non-ASCII service-specific keys
Bounty.bounty_type='credential' is no longer written. Pre-v1: no
historical backfill; existing rows stay untouched but unused.
595 tests pass; new tests cover the model + repo (upsert dedup,
null-principal independence, cross-service reuse, filters), both
ingester branches, b64 validation, sanitization preserving the
fingerprinting signal in b64.
Promotes auth-helper.c to decnet/templates/_shared/auth-helper/ and
adds _sync_auth_helper_sources() — mirrors the existing sessrec sync
pattern that keeps shared sources in step with per-template build
contexts.
Telnet's image grows the same multi-stage musl build, COPY of the
static helper into /usr/sbin/auth-helper, and prepended pam_exec line
in /etc/pam.d/login. Pulls in the `login` package (real Debian
PAM-aware /bin/login, replacing busybox's PAM-less applet) and
libpam-modules transitively for pam_exec.so.
Verified inside the rebuilt telnet image:
- /bin/login is the real 53KB Debian binary (PAM-aware)
- /etc/pam.d/login top line is the auth-helper hook
- pam_exec.so present at /usr/lib/x86_64-linux-gnu/security/pam_exec.so
- helper smoke-run emits correct RFC 5424 line for `telnetpw` →
password_b64="dGVsbmV0cHc="
SSH Dockerfile updated to read auth-helper.c from auth-helper/
subdirectory so both templates use the synced layout. The canonical
source lives in _shared/; per-template copies are tracked in git AND
synced at deploy time so a drift on either side rebases on the next
deploy.
Closes the telnet half of DEBT-038's #5 follow-up.
