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).
Add a NULL guard to protocol_release_memory_for_session so it no-ops like
the sibling session setters. Correct the Data.owner doc comment, which
implied a non-zero protocol_charge always has an owner; document that
owner may be NULL for uncharged/ownerless Data, that any such charge
falls back to the bound session, and that a charged Data must not outlive
its owning session. Note the lifetime contract on the release API too.
Extend tests/test_protocol.c to cover destroying a charged Data with no
session bound (the other half of the original bug) and to assert that
data_create/data_create_reserve start with owner == NULL and
protocol_charge == 0.
Document on utils_get_authorized_root_path() that the returned pointer is
borrowed and invalidated by the next authorized-root setter, that the fd
and path are not read atomically (non-reentrant), and that the fd remains
caller-owned. Add a matching single-threaded/set-before-threads note at
the accessor definitions in utils.c.
In server.c, drop the redundant utils_set_authorized_root(-1, NULL) after
a failed utils_set_authorized_root(): the setter already fail-closes the
state on allocation failure. The following close(root_fd) is unchanged.
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.
Data charged against a ProtocolSession kept only the charge amount, so
data_destroy released it from whatever session was thread-locally bound
at destroy time. Destroying a received Data on another thread, after the
session was unbound, or while a different session was bound leaked the
originating session's budget and underflowed the other's.
Add Data.owner, set it whenever protocol_receive_data_limited charges a
session, and have data_destroy release against that owner directly via
the newly-exported protocol_release_memory_for_session. Uncharged Data
(owner NULL) keeps the previous bound-session fallback.
Add a unit test proving a Data acquired on session A is released to A
even when unrelated session B is bound at destroy time.
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