Break the ~700-line parse_args god function into cohesive static helpers
grouped by concern: output controls, pre-negation, range/time options, the
OPTION_TABLE dispatcher, flag/meta handlers, IO/network options, filter and
logging options, checksum/socket options, remote/basis/identity options,
positional handling, and a final lowering step.
A file-local CliParseCtx carries the config, cursor, positional buffers and
the mutable parse flags, so each handler stays focused. The dispatcher calls
the handlers in the original recognition order and preserves the exact
return contract (0/1/negative), error messages, log levels and control flow.
Behavior preserved; no functional changes.
Type Config.super_mode as SuperMode (a proper C enum) instead of a bare
int. The wire boundary still carries the mode as an int: send casts the
enum explicitly and receive reads a temporary int, validates the
AUTO..OFF range, then casts. Emitted bytes and accepted values are
unchanged. ModuleGateContext.super_mode_override keeps its -1 sentinel
as int with an explicit cast at the apply site.
Behavior preserved.
Deduplicate the repeated directory-time capture gate
(`config->use_metadata && !config->omit_dir_times`) used by the
sender-side (multiprocessing.c) and receiver-side (receiver.c) sinks
into a single predicate declared next to the DirTimeList machinery in
file_receive.h and defined in file_receive.c.
Behavior preserved: identical short-circuit condition and semantics,
no signature or protocol changes.
- Protocol version 2.19.0 (SCRAM-SHA-256 daemon auth replacing the replayable digest)
- Salted PBKDF2 verifier store + --hash-credentials; legacy store hard-rejected
- Persistent anti-enumeration dummy key (<store>.dummykey)
- Verified TLS / opted-in loopback transport required for auth modules
- Secret wiping; carried-over hardening from the security phases
- Add CHANGELOG.md and set the CMake project version
- server gate: the --allow-unauthenticated loopback allowance now requires
an actual plaintext connection (!gate_ctx->ssl), so a loopback TLS client
whose cert fails the --client-cn check is refused before any SCRAM
challenge instead of falling through the plaintext opt-in. Keep the
invalid-fd guard as belt-and-braces (unreachable after the policy check).
- test: rewrote test_wrong_client_cn_refused_before_auth_challenge to run
deterministically over 127.0.0.1 with --tls + --allow-unauthenticated and
a CA-valid wrong-CN client cert, asserting the gate refusal log and an
unchanged module tree (no skip).
- docs: --client-cn is mandatory with --tls; dummykey sidecar is secret
material; document all transient-fallback reasons; qualify
--allow-unauthenticated in README and --help so it cannot read as
permitting remote plaintext auth.
- credentials.h: drop stale restrictive-umask claim (fchmod forces exact
0600; only create/write/fsync/link/fchmod failure degrades to ephemeral).
- Make the atomic-publish temp name unpredictable by appending 16 random
hex chars to the pid, so a leftover/planted temp cannot be targeted.
- On EEXIST, unlink the stale temp and retry the O_EXCL create once
(bounded), so a crash leftover or reused pid cannot silently defeat
sidecar persistence.
- fchmod the temp fd to 0600 after creation (umask can clear owner bits)
and treat failure as a create failure, so the published sidecar is
always exactly 0600.
- Clarify comments: the sidecar requires exact 0600 while the store and
password files only reject group/other bits.
- Add a unit test that a restrictive umask still yields an exact 0600
sidecar; clean random-suffixed temps in tests.
utils_fd_peer_is_local now returns true only when getpeername SUCCEEDS and the
peer address classifies as loopback. A non-socket descriptor (pipe/socketpair)
or any getpeername error is NOT local, so the daemon auth gate fails closed
instead of treating an untestable --stdio pipe as trusted (daemon auth modules
are --daemon-only and the stdio path never loads a daemon config).
server_module_gate now requires --allow-unauthenticated for the loopback
plaintext auth path: a plaintext loopback connection without the operator
opt-in is refused at the config gate BEFORE server_auth_handshake, so no SCRAM
challenge is sent. Remote peers still require verified TLS regardless of the
flag; the handler keeps its defense-in-depth checks.
Docs state the exact policy (verified TLS with matching --client-cn, or
operator-opted-in loopback plaintext), drop the SSH/stdio auth-transport claim
(they are daemon-only), and add the loopback trust-boundary relay caveat and
the CN-only (no SAN) residual. Adds a unit-test negative for pipe/socketpair
and an integration test where a relay observes no challenge when the flag is
absent.
Address review findings on the persistent dummy-key sidecar:
- Publish atomically: write a private same-directory temp file
(<store>.dummykey.tmp.<pid>, 0600), fsync, then link(2) into place;
fsync the containing directory and drop the temp name. A concurrent
starter can no longer observe a zero/partial sidecar and fail closed.
On EEXIST adopt the winner's sidecar; otherwise warn and use a
transient ephemeral key.
- Harden the read path (initial and EEXIST-adopt) with
O_RDONLY|O_NOFOLLOW|O_NONBLOCK|O_CLOEXEC: reject planted symlinks
(ELOOP fails closed) and never block on a planted FIFO.
- Require the exact owner-only mode (st_mode & 07777) == 0600 and make
the rejection message truthful.
- Report a clear "short write" instead of a stale strerror(errno) when
write() returns 0.
- Document the artifact and its creation-failure caveat (FIFO store
path, read-only filesystem, missing directory) in README.md and
RSYNC_COMPAT.md.
- Tests: known-key sidecar adoption (dummy salt KAT + reload), symlink
rejection, and the exact-0600 rule (0400 now rejected).
Daemon modules that declare 'auth users' no longer accept credentials over a
remote plaintext connection: server_module_gate refuses at the config gate,
before any SCRAM challenge is sent, unless the connection is verified TLS with
a client certificate matching --client-cn, or a local/SSH transport (loopback
TCP peer or the --stdio pipe). --allow-unauthenticated does not relax this.
The TLS client-CN comparison now uses credentials_secure_equal (S2). Clients
sending --password-file to a non-loopback daemon must use --tls; validate_config
rejects the plaintext case before any network I/O.
Adds utils_sockaddr_is_loopback / utils_fd_peer_is_local / utils_host_is_loopback
helpers with unit tests, a client validation unit test, and integration tests
for the client-side plaintext rejection and the wrong-CN gate refusal.
The store-wide dummy key was regenerated on every credentials_load, so an
unknown user's dummy salt changed across daemon restarts while a real user's
stored salt stayed stable -- a restart-gated username-enumeration oracle.
Persist the 32-byte key in a 0600 <store>.dummykey sidecar next to the
credential store. An absent sidecar is created with O_EXCL and fsynced; a
present sidecar is read only when it is an owner-only regular file of exactly
32 bytes (otherwise the load fails closed). If the sidecar cannot be created
(read-only mount, missing directory) fall back to a transient per-run key with
a warning. A NULL store path keeps the key ephemeral.
- burn the store-wide dummy_key in credentials_free()
- burn the local mac on hmac_sha256 failure in credentials_get_verifier()
- always run the O(store) constant-time scan, even for off-list users, to
close the pre-existing off-list timing channel; select the real verifier
only when on_list && match
- clarify the server_auth_handshake STATUS_AUTH_FAILED comment (failure
before success vs. a dropped broken connection while writing the signature)
- document accepted anti-enumeration residuals (restart-gated dummy salt;
pre-auth-observable iteration count)
- tests: pass CREDENTIAL_KEY_LEN to unhex for the 32-byte KAT proof/sig
(sizeof(expect) is 348, over-reading the 65-byte hex literal under ASan)
- credentials: close the username-enumeration oracle with a store-wide
dummy_key and a deterministic per-username dummy salt; make the store's
iteration count uniform (reject intra-file and layered disagreements) and
answer a miss with the store-wide count; run the constant-time key compare
even when found=false and fold the decision with bitwise AND
- credentials_compute_keys: enforce [CREDENTIAL_MIN_ITERS, CREDENTIAL_MAX_ITERS]
- tests: recompute the whole KAT independently at CREDENTIAL_DEFAULT_ITERS
(600000) and pin the golden store line; add non-uniform-store rejection,
bound and deterministic-dummy-salt assertions
- server: send exactly one generic STATUS_AUTH_FAILED on every failure path
(including credentials_get_verifier failure); route all handshake exits
through one burn path
- credentials/server: burn the base64 decoders' scratch on error, the
hash_store_line base64/line buffers on failure, and all handshake key/proof
material
- fuzz: guard the auth-offset scan against size_t underflow and use a found flag
- docs: drop stale digest wording, use CREDENTIAL_MIN_ITERS as the --iterations
bound, document 0600 output for --hash-credentials (plus a stderr warning on
a group/other-accessible stdout file), and describe the deterministic dummy
salt in the no-oracle claims
output_escape() was called on every send_str/receive_str even when
LOG_DEBUG_PROTO logging was disabled, allocating and scanning the whole
payload for a line that log_debug_message() then discarded. Add a
log_debug_enabled(flag) gate mirroring log_debug_message()'s own filter and
check it before escaping. Redacted (secret) strings still log the same
<redacted> marker; no observable log output changes.
- server_module_gate: refuse client-chosen ownership against the ORIGINAL config
so an explicit --super is still refused under an operator --no-super veto
(the veto must not turn a refusal into an accept).
- credentials: open-then-fstat the exact secret inode, require current-user
ownership and no group/other bits, but continue to allow process-substitution
FIFOs; removes the stat->fopen TOCTOU.
- file.c preallocate + protocol.c send-string debug logs escape attacker paths.
- usage/RSYNC_COMPAT updated for --old-args no-op and secret-file rules.
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