Follow-up to a237043 addressing three security/correctness re-review findings.
(1) MEDIUM: a server-contacting --dry-run with --compare-dest/--copy-dest/
--link-dest still read and hashed the basis file and compared it with the
client-supplied digest, a 1-bit content oracle. basis_match_find() gains a
hash_content parameter; the dry-run shortcut passes false and returns no
match without touching basis bytes, so an otherwise-matching entry is
reported as would-transfer. The real (non-dry-run) path is unchanged.
(2) LOW: xattr_capture_path() hardcoded preserve_acls=true, so the receiver's
hard-link copy fallback re-applied system.posix_acl_* even when -A was not
negotiated. The function now takes preserve_acls and members.* is
unaffected; scanner and receiver callers thread the negotiated flag.
(3) INFO: the --fsync --link-dest temp reopen now uses O_NONBLOCK and treats
a raced-in FIFO's ENXIO as a benign fsync-skip instead of blocking.
Tests: dry-run + basis unit test (asserts would-transfer, no content read) and
integration test; xattr capture ACL-filter test. Verified strict build, ASan,
clang-format, cppcheck, and the CI integration subset.
- parse_ull_arg() rejects a leading '-'/'+' (strtoull would silently wrap
-1 to ULLONG_MAX) and --chunk-size/--delta-max enforce their upper bounds.
- Escape local untrusted paths before logging (client_send, scanner,
--filter rule, pattern-file reads) with output_escape(..., 8-bit mode).
- Read --exclude-from/--include-from through the bounded line reader.
- Open --log-file with O_NOFOLLOW|O_CLOEXEC, mode 0600, via open+fdopen;
create --write-batch with O_NOFOLLOW|O_CLOEXEC, mode 0600.
- Reject --dry-run together with --write-batch (dry-run must not write the
batch file), alongside the existing --read-batch/--only-write-batch rules.
Tests: signed/oversized numeric rejection, over-long pattern file, dry-run +
write-batch unit and integration coverage.
Address confirmed receiver security findings B1-B6:
B1 (HIGH): add O_NONBLOCK to the three receiver read-opens that opened an
existing destination/basis entry before the S_ISREG gate
(incremental_check_open_destination, basis_open_regular, hardlink_read_source)
so a client-planted FIFO can no longer block the receive thread forever while
the post-open type gate still rejects it.
B2 (HIGH/MED): --inplace now fstatat(AT_SYMLINK_NOFOLLOW)-probes the target and
refuses any existing non-regular entry, opens with O_NONBLOCK, and re-checks
S_ISREG on the opened fd. This stops a FIFO from hanging the open and stops a
char/block device from being written directly (bypassing --write-devices).
B3 (MED): under --dry-run the incremental quick-skip no longer reads/hashes the
destination file for --checksum/--delta; it decides from metadata only and
reports would-transfer when the comparison is inconclusive, closing the
read-only-module content-hash oracle.
B4 (LOW): xattr_name_appliable() now gates the two system.posix_acl_* names on
preserve_acls (--acls), not the derived use_xattrs (--xattrs OR --acls). The
receiver drops (never applies) ACL entries when -A was not negotiated while
keeping user.* working for -X.
B5 (INFO): receive_manifest_section() charges a per-entry overhead against
MAX_MANIFEST_BYTES and the aggregate entry count across all three sections is
capped at MAX_MANIFEST_ENTRIES.
B6 (MED): data_charge_session() reserves decompressed/chunk-copy bytes against
the owning ProtocolSession (MAX_CONNECTION_MEMORY) and records them on the Data
so data_destroy() releases them via the Data.owner path. Applied to the
whole-file/append/delta decompression sites and chunk_deserialize() per-file
copies; a missing session owner degrades to the previous uncharged behavior.
Tests: FIFO destination/basis non-hang (with alarm), --inplace FIFO/device
refusal, dry-run no-read oracle test plus updated metadata-only dry-run tests,
ACL-without--acls drop, manifest total-entry cap, and chunk session charging.
C2: --force is deletion authority (an incoming regular file may remove a
non-empty destination directory tree, and --delete-missing-args may
remove a non-empty directory mirror), but it was not masked by the
operator --allow-delete policy. The handler now clears
config->force_delete unless --allow-delete was given, exactly like
--delete and --delete-missing-args.
C3: a standalone TCP / --stdio server running as root defaulted to
SUPER_MODE_AUTO, so an untrusted client --devices/--write-devices/
--super could make it create device nodes, write raw devices, or apply
client-chosen ownership. A privileged standalone receiver now forces
SUPER_MODE_OFF unless the operator opts in with the new server-only
--allow-super flag. Non-root receivers are unchanged, and the daemon
path keeps its per-module `client owner = yes` gate. --allow-super is
rejected with --no-super or --daemon.
C6: tls_client_identity_allowed now rejects a CN whose reported length
reached the buffer bound, so a truncated over-long CN cannot be matched
by a required --client-cn prefix.
Tests: an integration regression proving --force cannot replace a
destination directory without --allow-delete; standalone-default tests
for --copy-as refusal and (root-only) skipped device creation; a CLI
unit test for the new flag. The integration shared_server fixture opts
in with --allow-super so the existing root-only ownership/device/copy-as
tests continue to exercise the opted-in configuration. README and
RSYNC_COMPAT document the flag and the force/delete gating.
Extend _snapshot_tree to record mode, inode, xattrs, directories and
special nodes, and add coverage proving a server-contacting --dry-run
leaves the destination structurally identical for --delay-updates,
--backup, symlinks, hardlinks, FIFOs, and daemon modules (including a
read-only module). Add a regression test for the --read-batch --dry-run
refusal and for a missing/non-directory receive root failing a dry-run
exactly like a real run.
Fix stale version comments (2.20.0/633 -> 2.21.0/637) and RSYNC_COMPAT's
current --protocol value, and add a unit assertion that
--server-port/--port (and --server-host) set the dry-run routing bit.
--dry-run now handshakes with a remote/daemon receiver and reports what
WOULD transfer/skip based on receiver state, mutating nothing on either
side.
- Serialize Config.dry_run into the wire config frame and append
STATUS_DRY_RUN_TRANSFER to the status enum (no renumbering); bump
PROTOCOL_VERSION/CMake VERSION/CHANGELOG/golden wire to 2.21.0.
- Receiver: receive_incremental_check_ex runs the normal read-only
decision and answers STATUS_OK (skip) or STATUS_DRY_RUN_TRANSFER
(would transfer) with no basis materialization/append/delta/full
transfer. All mutation sites are guarded by !dry_run: file store,
manifest deletes, --mkpath root creation, --delay-updates staging,
publication, directory-time application, and outcome acks.
- Client: send_dry_run_remote connects, sends the config, checks each
regular file and prints the would-transfer set + trailer; no file data
or delete manifest is sent. Plain local destinations keep the
client-side manifest.
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).
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.
- 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).
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.
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.
- 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.
- file_ensure_directory_secure() now chowns a final directory it creates under
--copy-as and fails on error; the symlink parent-creation call site propagates
it. The is_dir branch fails when the confined parent cannot be opened under
--copy-as. Closes the residual wrong-owner gap for synthesized/symlink
parent directories.
- file_restore_symlink_metadata() early NULL return is copy-as-aware.
- Preserve errno across the implicit-parent failure cleanup.
- Neutral skip messages (the clamp, not --no-super, may be responsible).
- Daemon copy-as test tolerates the non-root privilege refusal; usage text lists
--copy-as.
- H3: a daemon module without 'client owner = yes' now also has super-user
device activity forced off (char/block mknod, --write-devices), so a root
daemon can no longer be made to create/write raw devices under AUTO. The
entries are skipped, preserving ordinary -a pushes.
- H1/H2: propagate a failed required --copy-as chown from symlink metadata
restore and implicitly-created parent directories, so the entry (and run)
reports failure instead of a wrong-owner success.
- Docs/help/headers updated for A2/A3 and the device clamp; startup warning
spells out the client-owner risk.
- Tests: daemon device clamp (skipped without opt-in, created with opt-in),
updated --super/--fake-super expectations.
A1: daemon refuses every client-chosen ownership/super-user request
(--numeric-ids/--chown/--usermap/--groupmap/--fake-super/--copy-as/--super)
unless the selected module opts in with 'client owner = yes'.
A2: fake-super owner replay requires an explicit ownership identity policy.
A3: --super no longer implies --numeric-ids (ownership stays opt-in).
A5: a failed --copy-as chown marks the entry failed instead of reporting
success with the wrong owner.
Add the receiver-side --super / --no-super tri-state (Config->super_mode)
under the safe-subset + clear-refusal privilege model: FastSync never
elevates privileges, it only permits super-user attempts that are already
confined fd-relative below the authorized receive root.
- identity: privilege_super_permitted() gate (OFF=false, ON=true, AUTO follows
geteuid()==0); identity_apply_ownership/_link become no-ops when not
permitted; --super with no explicit identity policy implies raw numeric-id
preservation (explicit usermap/groupmap/chown/numeric-ids still win); warn
exactly once when --super is requested by a non-root receiver.
- file_receive: gate char/block device-node creation on the gate; FIFO/socket
handling is unchanged.
- wire: trailing super_mode int after the --iconv spec, validated 0..2 in
receive_privilege_options and validate_received_config; PROTOCOL_VERSION
2.17.0 -> 2.18.0; version-sensitive tests and docs updated.
- CLI: --super/--no-super parsed explicitly before the generic --no-* branch
(malformed --super=x rejected); usage text added.
- tests: config wire round-trip + invalid-value rejection, privilege-gate mode
unit test, CLI parse test, integration transfer + root-gated ownership
suppression/appliance tests.
- docs: RSYNC_COMPAT --super row + Wave E note, protocol mentions, README.
Force the receiver to apply the requested owner/group to every written
entry through the confined fd-relative identity path instead of switching
the process credentials (unsafe for the multithreaded receiver). An
unprivileged receiver refuses the transfer up front in server_module_gate,
before STATUS_OK, so no data is written with the wrong ownership.
- new Config fields copy_as_set/copy_as_uid/copy_as_gid + defaults
- identity_parse_copy_as (name/@N/* resolution, primary-gid default,
gid==uid fallback for numeric ids with no passwd entry); implies -M
- identity snapshot + highest-priority forcing in identity_resolve_targets
- identity_copy_as_refused() helper
- trailing config-frame block (presence int + two int32 ids, >=0 checked)
- PROTOCOL_VERSION 2.17.0 -> 2.18.0; version-sensitive tests updated
- unit tests for parse + wire round-trip/negative-id rejection
- integration TestCopyAs: unprivileged refusal + root chown assertion
- RSYNC_COMPAT.md --copy-as row updated (safe subset + divergence); README
protocol version refreshed
Review fixes for Phase 7 Wave D.
#1 (HIGH): STATUS_DIR_TIMES entries no longer create directories. A new
receiver-only File.dir_time_only flag marks dir-time entries; file_save_to_disk_full
short-circuits them as FILE_SAVE_SKIPPED before any device/dir branch, so the sink
still accumulates metadata into the deferred DirTimeList but creates nothing. Empty
source dirs stay untransferred (-a), -m/--prune-empty-dirs semantics are preserved,
and a pre-existing regular file/symlink at an empty-dir mirror path no longer aborts
the transfer. dir_time_list_apply fstatat()s the leaf (AT_SYMLINK_NOFOLLOW) and skips
absent/non-directory paths QUIETLY; only a real existing directory is stamped.
Also initialize File.dir_time_only in file_create() (uninitialised garbage otherwise).
#2 (MED): send_dir_times() chunks entries into repeated STATUS_DIR_TIMES frames of at
most MAX_MANIFEST_ENTRIES, matching the receiver's per-frame bound; the tautological
> INT_MAX check is gone.
#3 (LOW): dir_time_list_add() assigns each grown array right after its realloc (no
dangling) and advances capacity only after both succeed.
#4 (LOW): RSYNC_COMPAT.md -- STATUS_MKDIR carries metadata, dir times are transmitted
via STATUS_DIR_TIMES and applied at the end, empty dirs are still never created; -m
rationale, -O row and Wave D notes updated. Summary counts untouched.
#5 (LOW): integration tests for the three #1 scenarios (empty-dir non-creation under
-a and -a -m, collision non-abort), scanner test now covers empty-dir capture, and
test_file_restore_symlink_metadata asserts the positive apply path when supported.
PROTOCOL_VERSION stays 2.17.0; config-frame layout unchanged.
Wave D of Phase 7. Make -O/--omit-dir-times and -J/--omit-link-times real by
preserving directory and symlink times, and mark --secluded-args as an explicit
Impossible/Divergence no-op.
Wire: PROTOCOL_VERSION 2.16.0 -> 2.17.0. Adds a terminal STATUS_DIR_TIMES frame
(int count + (wire path, metadata) pairs) sent after all file data and the
optional delete manifest. STATUS_MKDIR also carries metadata for --dirs entries.
Config-frame layout is unchanged.
Sender: the recursive scanner captures every traversed source directory (both
DirectoryScanner and the parallel scanner root + workers, appends mutex-guarded)
into a shared list; the single-threaded and -m paths transmit it last.
Receiver: a DirTimeList accumulates received directory metadata and applies it
with fd-relative no-follow utimensat only at the very end -- after all children,
after the commit-style --delete, and after --delay-updates publication -- in the
single-threaded success frame and in server.c after the -m threads join. -O skips
the application. Symlink metadata is applied at link creation with
utimensat/fchownat/fchmodat AT_SYMLINK_NOFOLLOW; -J suppresses only link times.
identity_apply_ownership_link shares the identity resolver with the fd path.
Docs: -O/-J rows -> Implemented; --secluded-args -> Impossible/Divergence;
--protocol accepted/rejected values and Phase-6/7 notes updated.
Tests: unit (scanner dir capture, DirTimeList apply, symlink metadata, protocol
version values) and integration (dir mtime round-trip + -O, symlink mtime
round-trip + -J, independent suppression), parameterized over single/multithread.
- fake_super_restore_fd now sanitizes mode like metadata_mode (never grants
S_IWGRP|S_IWOTH; 0666 -> 0644), fixing a privilege regression
- --sparse takes precedence over --preallocate (skip posix_fallocate when
sparse) so holes are not re-allocated; docs corrected
- --partial retention disabled under --no_replace (ignore/existing) and only
marks write_attempted after the write begins (no empty-temp retention)
- accept --block-size=SIZE / --delta-block=SIZE inline forms; neutral messages
- fake-super EPERM/EACCES skipped silently (docs aligned); EINVAL still logged
- sparse unit test now memcmp's the full buffer; TestBlockSize integration keeps
the destination basis so delta is genuinely exercised
- unit 37/37, cppcheck 0, clang-format 0
- write_all_sparse: skips all-zero runs >= 4096 bytes via lseek(SEEK_CUR) and
ftruncates the final size, wired into the atomic temp+rename and --inplace
paths with no wire change (full image already in memory).
- --partial retention: on a save failure after the temp held data, rename the
already-written temp to the destination path (best-effort; falls through to
unlink; never retains when --partial is off) so --append/--append-verify can
resume; tested by forcing futimens EINVAL with an out-of-range nsec.
- --block-size aliases --delta-block; verified config->delta_block_size is
honored by the delta engine end-to-end (unit + integration tests).
- fake_super_restore_fd: parses and re-applies user.fastsync.stat fd-relative
(fchown best-effort/non-root skipped, fchmod, futimens); a save under
--fake-super now both records and re-applies.
- -N/--crtimes and --stderr=client promoted to a new 'Impossible/Divergence'
status bucket (Summary: 136/2/4/3/2 = 147).
- cppcheck/clang-format clean; unit 37/37; integration 407 passed.
- revert over-eager replacement of setfacl -m in test_features.py
- use --chunk-serialization (+ set dirs) in the two append/append-verify
chunk-serialization rejection unit tests so they exercise the real check
- rename archive-negation integration test (--no-preserve is inert under
archive because devices/specials force metadata)
- update stale (-c)/(-m)/(-s)/(-f) display labels and RSYNC_COMPAT -c/-m refs
- document the --no-perms negation limitation in the Wave A note
-c -> --checksum, -m -> --prune-empty-dirs, -M -> --remote-option,
-f -> --filter, -s -> --secluded-args, -p -> --perms, -T -> --temp-dir;
-a/--archive is now real rsync -rlptgoD (links+metadata+devices+specials).
FastSync's own flags moved to long-form-only or new shorts:
-j/--threads (multithreading), --preserve (metadata), --sendfile,
--chunk-serialization, --timeout, --ssh-port. Client-side only; the
wire config fields are unchanged (no PROTOCOL_VERSION bump). The server
keeps -p as its port. Docs (README, RSYNC_COMPAT summary 129->132) and
unit/integration tests updated. 37/37 unit, 400-pass integration.
Implements the client-only residual-batch feature end-to-end:
- src/shared/batch.{c,h}: self-contained single-file batch codec using the
existing chunk_serialize/chunk_deserialize codec (byte-identical by
construction). Magic+format-version header (metadata mode is persisted into
the header so a batch is self-describing across machines), length-prefixed
chunk records, bounded reads that reject malformed/truncated/oversized
records cleanly.
- src/client/client_send.c: write_batch_from_source (deterministic separate
scan pass, loads every chunk's file images, emits header+records) and
apply_batch_to_dest (local apply to a destination root via
file_save_to_disk_full). No wire change, no server involved.
- src/client/client_validation.c: --write-batch XOR --only-write-batch;
--read-batch exclusive with both; --read-batch needs only a DEST,
--only-write-batch only a SOURCE.
- src/client/client_cli.c: main() drives the three batch modes without
connecting/transferring for read/only-write; --write-batch runs the live
transfer (single-threaded so the config survives) then emits the batch.
- tests/test_batch.{c,h} (unit: byte-identical roundtrip with and without
metadata; bad-magic/truncated/oversized rejection) + tests/integration/
test_batch.py (only-write no-server, read-batch no-source roundtrip,
--write-batch with a live transfer, conflict rejections).
- clang-format: realign PART-1 config.h comment block.
No PROTOCOL_VERSION bump, no config-frame field, no server flag.
- test_credentials.c: NUL-terminate the overlong-line stack buffer before
make_tmp_file's strlen() (was a stack-buffer-overflow READ under ASan);
still exercises the overlong-rejection path.
- Add redacted protocol string variants (protocol_send_str_redacted /
receive + fd send_str_redacted/receive_str_redacted) and use them for the
daemon auth username/digest so --verbose / LOG_DEBUG_ALL never logs a
replayable credential while other protocol strings keep their debug trace.
- credentials_verify/gate: replace byte-wise-short-circuiting strcmp with a
fixed-length constant-time username compare (closes user-enumeration oracle);
update doc comment to match.
- read_secret_file: preserve password exact bytes (only strip trailing CR/LF)
and burn the stack line buffer; document the whitespace behavior.
- test_server_cli.c: note the parser zero-inits opts on failure.
- Add debug-level daemon test asserting the digest never appears under --verbose.
PROTOCOL_VERSION stays 2.15.0.
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