Stamp host_last_use before publishing a bucket key and treat an unstamped
(last_use == 0) bucket as live, so a just-claimed bucket can no longer be
stolen by a concurrent reclaimer.
After a successful eviction CAS, re-scan for the interned key and, when an
earlier bucket already holds it, zero the duplicate's active count and
return the canonical bucket, preventing orphaned per-host counts and cap
overshoot under full-table concurrency.
Add a message-carrying EXPECT_FAIL primitive and use it for the daemon-conf
buffer-overflow guard, and add a fork-based test that records auth failures
from forked children and asserts the parent observes the shared lockout.
The config_receive_{basis,skip,idmap}_count helpers wrote the
peer-controlled int through the Config member before range-checking it.
An over-cap basis_count therefore left config->basis_count huge while
config->basis_dirs was still NULL; config_receive()'s error path then
called config_delete(), whose basis loop dereferenced NULL and crashed
the daemon before authentication.
Read each count into a local, validate, and only then assign, leaving the
member untouched on failure. config_delete() also guards the basis loop
with the array pointer as defense in depth.
Add a regression test that feeds over-cap basis/idmap/skip counts and
asserts rejection without crashing, plus a direct config_delete() check
on the partial (count set, array NULL) state.
Address low-severity review findings on the X-macro config refactor:
1. The golden test only hashed config_send_wire_block(), so a
receive-side KIND that reads a different width/order could still
round-trip symmetrically. Add test_config_wire_golden_receive():
capture the same hash-pinned 633-byte frame and feed it through
config_receive(), asserting every field (config_wire_equal) plus the
derived use_delta/use_xattrs bits and representative bounded kinds.
Add test_config_wire_receive_bounds() for bounds the symmetric
round-trip cannot reach: an out-of-range BOOL (hand-built frame),
RAW_MAXALLOC zero, a malformed STR_MODULE, an over-cap
INT_IDMAPCOUNT, and an out-of-range INT_IDENTITY chown_uid.
2. golden_config_populate() set long runs of booleans to all-1, so an
adjacent swap within a run produced identical bytes. Alternate the
boolean values and make the fixture receiver-valid (chmod grammar
"u=rwx,go=rx" is the same 11 bytes; delta_max_file_size inside the
bound). Re-pin the golden: len stays 633, hash is now
9160991280011164139 (computed, not guessed).
3. Document in config.h and client_cli.c that the CLI option tables
remain hand-maintained and are deliberately not generated from the
wire-field X-macro (client-only fields, flag/alias/negation
semantics). No CLI-table rewrite.
PROTOCOL_VERSION stays "2.20.0"; src/shared/config.c is untouched and
the wire bytes are unchanged apart from the fixture's own new values.
Every client on loopback shares the 127.0.0.1 identity, so counting them
against 'max connections per host' or the default-on auth lockout lets one
local client deny service to all the others (and makes a shared-NAT/proxy
address a natural DoS vector for remote clients). Use
utils_fd_peer_is_local (fail-closed) in the daemon gate to exempt a
provably local peer from the per-source cap and the auth lockout while
keeping the per-module and global caps. Remote peers are unchanged.
Document the shared-NAT/proxy identity limitation and the loopback
exemption in README/RSYNC_COMPAT/CHANGELOG, update the integration test to
assert the exemption, and fix the README 'auth failure delay' cap (5000,
not 60000).
The per-source host table only grew: once its fixed open-addressed table
filled, host_intern returned -1 and the per-host cap plus the shared auth
lockout silently failed open forever. Add a bounded-lifetime eviction
policy: track a per-bucket last-use time and, when no empty bucket exists,
atomically repurpose the first bucket that has no active connection and
either has an expired lockout or has been idle, resetting its counters.
Warn (rate-limited) on the genuine fail-open path.
A child SIGKILLed mid-registration could also leak a module/host count
because the parent only decremented on a REGISTERED slot. Make the slot
table the source of truth: after the SIGCHLD reap the parent recomputes
module_active[]/host_active[] from the surviving REGISTERED slots (atomics
only, async-signal-safe) so any leaked increment is erased.
Also clamp module_count to DAEMON_LIMITS_MAX_MODULES and use one helper
for the sizing/register host-tracking condition (a lockout threshold with
duration 0 is a no-op and must not intern hosts).
test_config_wire_golden() serializes a fully-populated Config through
config_send_wire_block() and pins the exact frame to len=633 and FNV-1a
hash 6163263374908258816, captured from the pre-X-macro implementation.
Any field reorder, resize or codec change fails the test.
test_config_wire_roundtrip_all_fields() serializes/deserializes a defaults
Config and a fully-populated Config over a socketpair and compares every
serialized field. The comparison is itself generated from
CONFIG_WIRE_FIELDS (one CONFIG_CMP_<KIND> per table entry), so a new table
entry automatically extends coverage; it cannot fall out of sync. It
normalizes the receiver's NULL/"" canonicalization, the max_alloc server
clamp and the derived use_delta/use_xattrs bits.
Every Config field that crosses the wire was declared in up to six places
(struct member, config_set_defaults, send_*, receive_*, and the two CLI
option tables) and could drift silently. Add CONFIG_WIRE_FIELDS in
config.h: one ordered per-segment table where each serialized field is
declared once with its C type, default and wire codec (KIND).
config.h now expands the table to declare the struct members;
config_set_defaults() expands it to assign the defaults; and
config_send_wire_block()/config_receive() expand the per-segment lists to
emit/consume the frame. The per-segment function names, call order and
segment boundaries are preserved exactly.
Fields with genuinely custom logic keep dedicated helpers but are still
declared once in the table: the protocol-version handshake (HEADER), daemon
SCRAM auth (STR_REDACTED_AUTH), the daemon module name (STR_MODULE), the
repeated count+array blocks (BLOCK_SKIP_SUFFIXES/BLOCK_BASIS/BLOCK_IDMAP),
--copy-as presence/ids (COPY_AS_*), and the derived --delta / use_xattrs
bits (DERIVED_DELTA, BOOL_XATTR_DERIVE). The version field remains a
special header (validated before any other field is parsed) and is sent by
config_send_wire_block() explicitly.
No public field is renamed and PROTOCOL_VERSION stays "2.20.0". Because
the struct declaration order is no longer the wire order, the wire order is
now enforced solely by the table and by a byte-exact golden test
(follow-up commit). Add config_send_wire_block() so that test can hash the
frame body without the STATUS_OK handshake.
Wire the shared registry into the accept loop (parent claims a slot before
fork, blocks SIGCHLD across fork+pid publication, and reclaims the dead
child's slot from the SIGCHLD handler so per-module/per-source counts are
released even on SIGKILL). The connection child records the selected module
and normalized peer IP once the config frame names them: an over-cap module
or source is refused at the config gate with an audit log, and a source
that exceeded the auth-failure threshold is refused before a SCRAM
challenge (the counter is shared across children and cleared on success).
The existing global cap and host ACLs are untouched.
Add global keys `max connections per host` (default 0 = unlimited),
`auth lockout threshold` (default 10, 0 disables) and
`auth lockout duration` (default 300 s, 0 disables). Module
`max connections` now accepts 0 as unlimited. Bound the number of
[module] sections (DAEMON_CONF_MAX_MODULES) so the shared registry's
per-module counter array stays fixed-size; absent keys keep their
defaults so old configs still load.
The daemon forks one child per accepted connection, so per-module and
per-source accounting must live in state shared across the children. Add a
fixed-size registry carved from an anonymous shared mapping
(mmap(MAP_SHARED|MAP_ANONYMOUS)) created before the accept loop: a slot
lifecycle (FREE/CLAIMED/REGISTERED) with parent claim/reclaim and a
lock-free, open-addressed per-source table for the per-host occupancy and
the shared auth-failure counter. C11 atomics only; no pthread locks across
fork.
Unit tests cover slot exhaustion, the module/host caps, pid reclaim and
fork-shared visibility.
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.
Add two libFuzzer harnesses (GLOBbed from tests/fuzz/*.c) and deterministic
P8 config-frame receive tests:
- fuzz_config_receive.c drives config_receive() from arbitrary bytes. It
captures one canonical valid frame with the production sender and feeds the
receiver four shapes: raw bytes, valid-version-prefix + fuzz bytes, valid
frame minus the P8 tail (super_mode + copy-as) + fuzz bytes, and valid frame
minus the usermap count + fuzz bytes. This reaches the --super/--copy-as and
huge/negative map-count paths that random bytes cannot get through the
preceding wire-bool gate.
- fuzz_identity_parse.c fuzzes identity_parse_copy_as/map/chown plus the
identity_wire_valid/identity_ownership_requested predicates on a fresh
config per input.
- test_fuzz_smoke.c gains deterministic malformed-frame cases: out-of-range
super_mode, negative/extreme copy-as ids, non-bool copy-as presence, tail
truncation, huge/negative usermap counts, version mismatch and a
wrong-order field after the version gate.
Unit build (STRICT_WARNINGS) and the fuzz build are clean; both targets run
3000+ iterations with no crash. No production code changed.
- A6: escape attacker-controlled file paths and the receive root in log
lines (file_receive, server, protocol DEBUG) with output_escape()
- A8: identity_set_active() returns bool and fails closed when a requested
usermap/groupmap cannot be deep-copied; handler refuses the connection
- remove the const cast and duplicate super_mode clamp from
server_module_gate via an explicit override the handler applies once
- release the identity snapshot on the queue_create failure path
- refactor identity_parse_copy_as to a single cleanup tail and drop the
duplicated group error format specifier
- file: open -K dirlink referents via a race-safe relative O_NOFOLLOW walk
from the authorized-root fd instead of re-opening an absolute realpath()
result (removes the intermediate-symlink swap TOCTOU).
- transport_ssh: always single-quote the server path, including --old-args,
so no mode can inject shell metacharacters.
- transport_tls: set SSL_OP_NO_COMPRESSION and (guarded) SSL_OP_NO_RENEGOTIATION.
- credentials: reject --password-file/--early-input with any group/other
permission bit; chmod 0600 the affected test fixtures.
- file_store: export file_store_write_sparse() and remove the verbatim
file.c duplicate.
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