util/crc32.hpp — header-only CRC-32 (zlib polynomial, reflected), used to
integrity-check the sidecar.
meta/veloxpart — the <name>.veloxpart.meta resume file (docs/04 §5).
Little-endian, versioned, CRC-32 over the whole record. Layout: magic,
version, flags, total_size, downloaded, url set (original/effective/
mirrors), etag/last-modified/content-type, segment records (start, end
INCLUSIVE, completed), optional sha256 streaming-hash blob.
parse_veloxpart() is the attacker-facing surface (the file sits in a
world-writable-ish download dir) and is total on any byte string: CRC
checked before any field is interpreted; magic, a version it understands,
every count and length bounded by a hard cap AND checked against the
remaining buffer; ByteReader latches on overrun; trailing bytes rejected.
Every malformation is meta_corrupt / meta_version_unsupported, never a
crash or an unbounded allocation. serialize_veloxpart() is deterministic
(unchanged sidecar isn't rewritten). File helpers write atomically
(temp + rename) and fdatasync the file and its directory.
Tests: crc32 known vector; full + minimal round-trips; deterministic
serialize; file round-trip; and a truncation/corruption table — bad
magic, CRC mismatch (payload and CRC-field flips), future version,
truncation at every stage, hostile url_count / segment_count / lp_string
length (the case the brief singles out), trailing bytes, impossible
segment.completed.
tools/fuzz/fuzz_veloxpart — feeds raw bytes and bytes-with-valid-CRC
(so the field parser and ByteReader bounds checks are actually reached),
and round-trip-stability-checks anything accepted. Ran 1.1M execs clean
under ASan+UBSan+libFuzzer (clang++-21); fuzz_content_disposition and
fuzz_url likewise re-run to 1.1M. tools/fuzz gains a -runs=0 seed-replay
CTest smoke per target (regression tripwire; the campaign stays manual).
Fuzz-found and fixed: parse_content_disposition could emit a filename
containing NUL / control bytes from a mangled filename* ext-value —
strip_path only removed path separators. Now sanitize_leaf() also drops
C0 controls and DEL (rules/ still owns the authoritative sanitize; `..`
and printable-unsafe content pass through as before).
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HPPSGhiArbvQgwC2DNiURS
net/content_disposition — total parser for the mojibake-prone header:
RFC 6266 filename (quoted/token), RFC 5987 filename* ext-values
(charset'lang'pct-encoded, incl. RFC 2231 continuations), legacy RFC 2047
encoded-words (=?UTF-8?B?..?= / ?Q?), and raw Latin-1 bytes; prefers
filename* over filename; strips path components AFTER decoding (a base64
payload can hold '/'). 22-case test table.
net/text_codec (internal) — percent-decode, UTF-8 validation, Latin-1->
UTF-8, base64, RFC 2047 — shared by the CD parser and the URL splitter.
net/url — a small total URL splitter (scheme/userinfo/host/port/path/
query/fragment, http(s) validity) and url_filename() for the last path
segment; used for the filename fallback.
net/probe — HEAD then a ranged GET bytes=0-0 that PROVES resumability
(206 + matching Content-Range + a validator), rather than trusting
Accept-Ranges which servers lie about; the ranged GET is also the HEAD-
refused (403/405/501) fallback. 401/407 -> success result with
requires_auth, not an error. Runs on its own pool (max_concurrent,
default 4) outside the segment budget per ADR 0011 §5. suggest_filename()
does the resolution order (explicit -> disposition -> URL -> download.bin)
with a light strip; rules/ (stage 9) owns the authoritative sanitize.
tools/fuzz — libFuzzer targets for the CD parser and the URL splitter,
compiling the parser sources directly so they're fully instrumented;
self-guards on VELOX_BUILD_FUZZ + Clang (the top-level CMake adds every
tools/* unconditionally). Seed corpora included.
Fixed on the way: a p -> Transfer -> State -> cbs -> p reference cycle in
Prober that leaked every probe (drop the stored Transfer; the worker
keeps State alive). Tests green under ASan/UBSan and TSan.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HPPSGhiArbvQgwC2DNiURS
One HttpClient owns a small pool of workers, each with its own CURLM; an
easy handle lives on one worker for its life. Public start/pause/resume/
cancel enqueue a command + curl_multi_wakeup(); callbacks (on_head /
on_data / on_finished) run on the worker thread and return a DataAction
(proceed / pause / abort). Covers redirects (final-response head only),
ranges (inclusive ByteRange -> CURLOPT_RANGE), proxy/SOCKS5, basic/digest
auth, cookies, verbatim headers, stall detection, a coarse recv-rate cap,
and a curl_share DNS/TLS cache across workers. CURLcode + HTTP status ->
vdm::Error in net/curl_error. A probe is on_head returning abort: it
finishes successfully (head_complete), not canceled.
Tests drive tools/testserver: full GET, ranged 206, redirect chain, 404
-> not_found, connection refused -> connect_failed, HEAD probe + ranged
0-0 probe (no body), cancel mid-transfer, pause/resume completes. Skip
cleanly if testserver isn't in the tree.
Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HPPSGhiArbvQgwC2DNiURS
samiandClaude Sonnet 5