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.
- 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
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.
TapTap