Three receiver security fixes from the audit:
1. --temp-dir symlink escape (High): file_open_temp_dir() opened the
client-controlled scratch dir with a bare open(), so a symlink planted
under the receive root let a peer redirect receiver scratch files
outside the authorized root. The opened dir is now judged by the REAL
path of its fd (via /proc/self/fd), and any target outside the
authorized receive root is refused with a logged error (EACCES). An
in-root symlink (the EXDEV cross-filesystem fallback case) still works,
and the no-root local batch path is unchanged.
2. setuid/setgid/sticky under SUPER_MODE_OFF (High): the special bits were
applied under --perms (and via --chmod) even when the connection forbade
super-user activities. FileAttrPolicy gains super_permitted, set by
file_attr_policy_from_config() from privilege_super_mode_permitted();
metadata_mode_for_policy(), the symlink path, the special-node creation
path, and the deferred directory-mode apply now strip the special bits
when it is false. Exact rsync semantics are preserved when permitted.
3. daemon umask (Low): daemonize() forced umask(0), so implied parent
directories created without -p were world-writable 0777. Set the
conventional daemon umask 022 instead (rsync never forces 0); -p/-a mode
preservation is unaffected because it restores modes via fchmod.
Tests: new unit tests for file_open_temp_dir confinement and the
masked/unmasked special-bit policy (incl. the --chmod path), a daemon
world-writable-dir regression test, an integration escape test, and a
root-only integration test asserting special bits are masked without
--allow-super. The old cross-filesystem test encoded the vulnerable
behavior (symlink target outside the root) and is replaced by the escape
test; the EXDEV fallback code is retained for in-root links.
- --chmod no longer implies --preserve-perms; repeated --chmod options
accumulate, and D/F/X selectors plus s/t special bits are supported with
rsync's exact parse_chmod/tweak_mode semantics.
- Stop masking group/other write and setuid/setgid/sticky: -p copies the
source mode exactly, no-p new entries use source&~umask, directories keep
setgid/sticky, and special nodes follow the same rules.
- Apply ownership before mode on the fd path so a chown cannot clear the
setuid/setgid bits -p just restored (rsync order).
- Update unit and integration tests, including differential checks against
rsync 3.4.1.
Split FastSync's single use_metadata bundle into four independent rsync-parity attributes: preserve_perms, preserve_times, preserve_owner, preserve_group. use_metadata is now a derived transport bit (config_derived_use_metadata).
CLI: real -p/--perms, -t/--times, -o/--owner, -g/--group plus --no-perms/--no-times/--no-owner/--no-group (short and long) and --no-preserve; -a is now rsync -rlptgoD; --preserve = -pt; -A implies -p; -X does not; --chmod implies -p; --usermap/--groupmap/--chown imply owner/group per side; --incremental/--delta still auto-preserve unless negated.
Receiver: per-attribute FileAttrPolicy gating for files, dirs (modes applied at end of transfer), symlinks and specials; rsync -E read-bit rule; new files get source_mode & ~umask sanitized (no group/other write); per-side identity resolution; deferred directory metadata; batch dir-metadata replay; daemon modules without 'client owner = yes' no longer refuse plain -a but force super off (no ownership) with a warning.
Wire: PROTOCOL_VERSION 2.21.0 -> 2.22.0 (four appended config bools, golden 653 / 95530566005420798). FileMetadata/chunk/batch framing unchanged. Docs/CHANGELOG/CMake updated to 2.22.0.
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.
Capture+transmit source atime (pre-read stat; O_NOATIME sender guard) and birth
time (statx STATX_BTIME); receiver restores atime with mtime (crtime not settable
portably -> transmitted, explicitly not applied). --open-noatime is client-only.
-O/-J documented as accepted no-ops (FastSync never preserves dir/symlink times).
Wire: metadata frame gains atime/crtime val+sec+nsec; PROTOCOL_VERSION
2.11.0->2.12.0. Review fixes: gate atime capture to Linux (no epoch clobber on
non-Linux), close fd on fdopen failure, honest -O/-J status (Compat no-op).
metadata_mtime_matches() required exact nanosecond equality at the default
modify_window=0, but destination write-time nsecs never match source
creation-time nsecs unless -M preserves metadata. Compare whole seconds
(rsync's default quick-check) at window 0; keep the subsecond-refined
tolerance for explicit window values.
- Remove unused ConsumerCtx struct in test_stress.c
- Add const qualifiers to variables only checked for NULL
in test_metadata.c, test_protocol.c, test_robustness.c
TapTap