feat(analyzer): TLS handshake-message reassembly across records (STORY-144, closes SNI/JA3 fragmentation evasion) by Zious11 · Pull Request #341 · Zious11/wirerust

Zious11 · 2026-06-30T02:23:45Z

Summary

TLS carry buffer and ClientHello fragmentation reassembly (STORY-144, Wave 65, E-5). An adversary who splits a TLS ClientHello across multiple TLS 0x16 records could evade SNI-based detection and JA3 fingerprinting on develop (baseline: SNI=MISSED, JA3=MISSED, parse_errors=2). This PR closes that evasion gap by implementing a per-direction carry buffer in TlsFlowState that accumulates record payloads and dispatches handle_client_hello only when the full handshake message is assembled.

Evasion closed: fragmented ClientHello → SNI: ['example.com'], JA3: 6169fabc98e3e6c9..., parse_errors: 0.

Architecture Changes

graph TD
    A["TLS Record (0x16)"] --> B{direction}
    B -->|ClientToServer| C["client_hs_carry: Vec<u8>"]
    B -->|ServerToClient| D["server_hs_carry: Vec<u8>"]
    C --> E{overflow check}
    E -->|len + payload > MAX_BUF| F["clear + handshake_reassembly_overflows += 1"]
    E -->|ok| G["carry.extend_from_slice(payload)"]
    G --> H{drain loop}
    H -->|carry < 4| I["break: wait for more data"]
    H -->|body_len > MAX_BUF| J["clear + overflow += 1, break"]
    H -->|carry < 4 + body_len| I
    H -->|complete message| K{msg_type}
    K -->|0x01 ClientHello| L["parse_tls_message_handshake → handle_client_hello"]
    K -->|other| M["consume silently"]
    L -->|Ok| N["carry.drain(..4+body_len), loop"]
    L -->|Err| O["parse_errors += 1, carry.drain(..4+body_len), loop"]
    M --> N

Files changed: src/analyzer/tls.rs (+330/-69 lines), tests/tls_analyzer_tests.rs (+1076 lines), tests/dispatcher_tests.rs (+76/-0 lines), docs/demo-evidence/STORY-144/ (4 recordings + evidence-report.md).

No changes to src/reassembly/, src/dispatcher.rs, src/findings.rs, src/reporter/, or tests/tls_integration_tests.rs. SS-07 (analyzer/tls.rs) only.

Story Dependencies

graph LR
    STORY144["STORY-144 (this PR)"]
    STORY145["STORY-145 (ServerHello carry)"]
    STORY146["STORY-146 (buffer_saturation_drops counter)"]
    STORY144 --> STORY145
    STORY144 --> STORY146

depends_on: [] — no upstream story PRs required before this merge.
blocks: [STORY-145, STORY-146] — STORY-145 (ServerHello direction carry) and STORY-146 (buffer_saturation_drops counter) depend on this PR merging first.

Spec Traceability

flowchart LR
    BC038["BC-2.07.038 v2.7\nHandshake Reassembly\nAcross Record Boundaries"]
    BC039["BC-2.07.039 v2.4\nCarry Buffer Bounded\nat MAX_BUF"]
    BC040["BC-2.07.040 v1.3\nTruncated Carry\nSilent Discard"]
    BC042["BC-2.07.042 v1.4\nCoalesced Messages\nDrain Loop"]
    BC001["BC-2.07.001 v1.9\nParse Complete\nClientHello"]
    VP039["VP-039\nCarry Reassembly\nVerification Property"]

    BC038 --> AC144001["AC-144-001\nStruct fields +\ncounters"]
    BC038 --> AC144002["AC-144-002\nDrain loop +\ndispatch"]
    BC039 --> AC144003["AC-144-003\nOverflow clear-\nand-recover"]
    BC040 --> AC144004["AC-144-004\non_flow_close\nsilent discard"]
    BC001 --> AC144005["AC-144-005\nSingle-record\nregression"]
    BC042 --> AC144002
    VP039 --> AC144002

    AC144001 --> T001["test_BC_2_07_038_canonical_frame_rfc8446_s4\ntest_BC_2_07_038_malformed_assembled_body\ntest_vp039_sni_boundary_deterministic"]
    AC144002 --> T002["proptest_vp039_carry_reassembly_two_record\ntest_vp039_n_record_reassembly\ntest_vp039_large_valid_hello_reassembly\nproptest_vp039_exact_consume_coalesced\ntest_BC_2_07_042_exact_consume_no_double_dispatch\nproptest_vp039_carry_bounded_invariant"]
    AC144003 --> T003["test_vp039_carry_overflow_clear_and_recover\ntest_vp039_carry_overflow_recovery\ntest_vp039_body_len_spoof\ntest_BC_2_07_039_summarize_exposes_handshake_reassembly_overflows_key"]
    AC144004 --> T004["test_vp039_truncated_carry_no_error\ntest_BC_2_07_040_empty_carry_flow_close"]
    AC144005 --> T005["all 120 existing tests"]

    T001 --> IMPL["src/analyzer/tls.rs\n(TlsFlowState.client_hs_carry,\nserver_hs_carry;\nTlsAnalyzer.handshake_reassembly_overflows)"]
    T002 --> IMPL
    T003 --> IMPL
    T004 --> IMPL
    T005 --> IMPL

Test Evidence

Metric	Value
Total tests passing	136
STORY-144 Red-Gate tests (new)	15 (VP-039 Sub-A/B/C/D/F)
Anti-quadratic regression test	1 (SEC-001 O(1) cursor-drain)
Existing tests preserved	120
Clippy (-D warnings)	Clean
cargo fmt --check	Clean
tls_integration_tests.rs	Pass (tls.pcap, tls12-aes256gcm.pcap, tls13-rfc8446.pcap)

15 new test harnesses (all in mod story_144 {} per DF-TEST-NAMESPACE-001):

Test	Sub	BC	Type
`proptest_vp039_carry_reassembly_two_record`	Sub-A	BC-2.07.038	proptest
`test_BC_2_07_038_canonical_frame_rfc8446_s4`	Sub-A	BC-2.07.038 AC-CANONICAL-FRAME	unit
`test_BC_2_07_038_malformed_assembled_body`	Sub-A	BC-2.07.038 PC-9	unit
`test_vp039_sni_boundary_deterministic`	Sub-A	BC-2.07.038 EC-001	unit
`test_vp039_n_record_reassembly`	Sub-A-ext-N	BC-2.07.038 EC-003	unit
`test_vp039_large_valid_hello_reassembly`	Sub-C-ext-large	BC-2.07.038 Inv-5	unit
`proptest_vp039_exact_consume_coalesced`	Sub-B	BC-2.07.042	proptest
`test_BC_2_07_042_exact_consume_no_double_dispatch`	Sub-B	BC-2.07.042	unit
`test_vp039_carry_overflow_clear_and_recover`	Sub-C	BC-2.07.039 PC-1-6	unit
`test_vp039_carry_overflow_recovery`	Sub-C	BC-2.07.039 PC-6	unit
`test_vp039_body_len_spoof`	Sub-C	BC-2.07.038 Inv-5	unit
`test_BC_2_07_039_summarize_exposes_handshake_reassembly_overflows_key`	Sub-C	BC-2.07.039 PC-7	unit
`test_vp039_truncated_carry_no_error`	Sub-D	BC-2.07.040	unit
`test_BC_2_07_040_empty_carry_flow_close`	Sub-D	BC-2.07.040	unit
`proptest_vp039_carry_bounded_invariant`	Sub-F	BC-2.07.039 Invariant 1	proptest

Demo Evidence

Headline: Before / After (AC-144-002)

The fragmented ClientHello pcap was MISSED on develop before this fix:

Before (develop baseline)	After (STORY-144)
SNI: (empty — MISSED)	SNI: ['example.com']
JA3: (empty — MISSED)	JA3: 6169fabc98e3e6c9...
parse_errors: 2	parse_errors: 0

Recording: docs/demo-evidence/STORY-144/AC-144-002-before-after-contrast.gif

AC-144-002: Fragmented ClientHello Reassembly

AC-144-002-reassembly-fragmented.gif — tls-clienthello-fragmented.pcap against STORY-144 binary. Shows SNI=['example.com'], JA3 hash, parse_errors:0.

AC-144-002: Single-Record Regression (Control)

AC-144-002-control-regression.gif — tls-clienthello-control.pcap against STORY-144 binary. SNI still extracted; no regression on single-record path.

AC-144-003: Carry Overflow Clear-and-Recover

AC-144-003-overflow-clear-recover.gif — cargo test run of test_vp039_carry_overflow_clear_and_recover + test_BC_2_07_039_summarize_exposes_handshake_reassembly_overflows_key. Both pass. Shows the Decision-5 guard fires and handshake_reassembly_overflows is surfaced in summarize().

All demo evidence is in docs/demo-evidence/STORY-144/evidence-report.md.

Holdout Evaluation

N/A — evaluated at wave gate (Phase F4 holdout scenarios HS-F4-001 through HS-F4-006 are gated at the wave level, not per-PR).

Adversarial Review

3 clean adversarial passes (BC-5.39.001) completed during implementation. All findings from the 3 cycles were triaged and resolved before PR creation.

Security Review

Finding	Severity	Status
SEC-001: Quadratic carry drain O(n²) — `extend+drain` on each loop iteration caused O(n²) on large coalesced messages	HIGH	RESOLVED — refactored to cursor-based O(1) drain; anti-quadratic regression test added (`test_sec001_no_quadratic_drain`)
SEC-002: Narrow non-RFC window — overflow guard uses `==MAX_BUF` condition edge (non-RFC exact boundary)	LOW	DEFERRED to F6 — narrow window [MAX_BUF-3, MAX_BUF], no real exploit path; tracked as deferred item
SEC-003: `saturating_add` missing on `handshake_reassembly_overflows` counter	LOW	RESOLVED — counter now uses `saturating_add(1)` to prevent u64 overflow

No CRITICAL or HIGH unresolved findings.

Risk Assessment

Dimension	Assessment
Blast radius	Single-file Rust change (SS-07 / src/analyzer/tls.rs); no protocol boundary changes; no public API changes
Behavioral regression risk	LOW — single-record fast path preserved; 120 existing tests pass; carry is empty → extend → drain → empty on single-record path
Performance impact	O(1) per-record amortized; SEC-001 resolved (cursor drain eliminates O(n²) hot path); carry Vec heap allocation bounded at MAX_BUF (65,536 bytes) per direction per flow
Forward compatibility	Direction-parameterized drain loop (match on direction) designed so STORY-145 can add ServerHello path by adding one match arm
Security posture	SNI/JA3 evasion via TLS record fragmentation (TLS-CLIENTHELLO-FRAG-001) closed; carry overflow guard prevents DoS from carry amplification

AI Pipeline Metadata

Field	Value
Pipeline mode	Feature cycle (fix-tls-clienthello-frag)
Story wave	Wave 65
Story points	8
Phase	F3 (incremental TDD)
Factory VSDD version	VSDD-F-mode
Model	claude-sonnet-4-6

Deferred Items

Item	Status	Target
SEC-002: narrow non-RFC overflow window `==MAX_BUF` vs `>MAX_BUF`	DEFERRED	F6 hardening
`done()`-mid-loop cross-direction carry interaction	DEFERRED	wave-gate review — pre-existing behavior, not a STORY-144 regression

Pre-Merge Checklist

Files created: src/analyzer/tls.rs (modified), tests/tls_analyzer_tests.rs (modified) todo!() functions: 3 (proptest_vp039_carry_reassembly_two_record, proptest_vp039_exact_consume_coalesced, proptest_vp039_carry_bounded_invariant) ## GREEN-BY-DESIGN none ## WIRING-EXEMPT none Stub details: - TlsFlowState: added client_hs_carry: Vec<u8> and server_hs_carry: Vec<u8> (both Vec::new() in new()); NO hs_carry_abandoned flag (BC-2.07.039 Inv-4) - TlsAnalyzer: added handshake_reassembly_overflows: u64 (init 0); aggregate counter, NOT per-flow, NOT reset at on_flow_close (mirrors truncated_records) - 4 new #[doc(hidden)] pub fn test seams on TlsAnalyzer: client_hello_seen_for_testing, client_hs_carry_len_for_testing, server_hs_carry_len_for_testing, handshake_reassembly_overflow_count - parse_tls_message_handshake import added (ADR-011 Decision 4 parse boundary); #[allow(unused_imports)] stub suppresses -Dwarnings until drain loop is wired - summarize(): handshake_reassembly_overflows insertion LEFT for implementer (adding it now would break test_summarize_output; implementer adds key + updates the expected-key-count assertion together in AC-144-002/003) - try_parse_records: existing parse_tls_plaintext path PRESERVED (AC-144-005 regression gate); carry drain loop is the implementer's task (AC-144-002) - mod story_144 in tests/tls_analyzer_tests.rs: 15 Red Gate harnesses per DF-TEST-NAMESPACE-001; all 15 FAIL (Red Gate intact), 120 existing tests GREEN BC-5.38.001 compliance: cargo check passes, cargo clippy --all-targets -D warnings passes, all 15 new tests are RED, no non-trivial function body contains real implementation logic. The 3 proptest stubs use todo!() per BC-5.38.001. The 12 unit stubs assert carry-path behavior (carry accumulation, overflow counts, SNI extraction after fragmentation) that ONLY the carry drain loop can satisfy.

…mbly (VP-039) Finalizes mod story_144 in tests/tls_analyzer_tests.rs: replaces the three todo!() proptest stub bodies with real falsifiable proptest implementations, converts unused doc-comment warnings to // style, fixes clippy::len_zero. All 15 VP-039 harnesses (3 proptest + 12 unit) compile clean and FAIL against the current carry-drain-loop stubs (Red Gate per BC-5.38.001): - proptest_vp039_carry_reassembly_two_record (Sub-A): fails because client_hello_seen stays false without the carry path - proptest_vp039_exact_consume_coalesced (Sub-B): fails on carry_len==4 assertion after the 4-byte header record (stub returns 0) - proptest_vp039_carry_bounded_invariant (Sub-F): fails on carry >= 1 secondary assertion after first partial record (stub returns 0) - 12 unit tests: fail on existing carry/overflow/summarize assertions 120 pre-existing tests still pass; cargo clippy -D warnings clean.

…on reassembly Implements BC-2.07.038 v2.5 / BC-2.07.039 v2.4: per-direction client_hs_carry Vec<u8> on TlsFlowState accumulates 0x16 record payloads across record boundaries until a complete handshake message (4-byte header + body) is assembled. Key decisions implemented: - Decision-3 (ADR-011): append payload → drain loop dispatches complete messages - Decision-4: body_len > MAX_BUF → clear carry + handshake_reassembly_overflows++ - Decision-5: carry + payload > MAX_BUF BEFORE append → clear + overflows++ + continue - Direction-split: ClientToServer uses carry path; ServerToClient retains parse_tls_plaintext (STORY-145 scope) to preserve all ServerHello tests (AC-144-005) - parse_tls_message_handshake used for carry dispatch (not parse_tls_plaintext which requires a 5-byte TLS record header absent from assembled carry bytes) Test fixture fixes: - test_vp039_carry_overflow_clear_and_recover: replaced single 65,400-byte record with 4 records (3×18,432 + 10,104) per BC-2.07.039 v2.1 EC-002: single records > MAX_RECORD_PAYLOAD (18,432) cannot reach the carry; overflow is accumulation-based - test_vp039_carry_overflow_recovery: replaced single 65,537-byte record with 4×18,432-byte records; same spec rationale - test_parse_error_counter + test_malformed_handshake_increments_parse_errors_only: updated fixture to 9-byte TLS record carrying a complete-but-malformed handshake message so the drain loop assembles it → parse_tls_message_handshake fails → parse_errors++ - test_summarize_output: updated key count 7→8 for handshake_reassembly_overflows - dispatcher_tests (6 tests): changed discriminator from parse_error_count/truncated_record_count to active_flows_len_for_testing — carry path accumulates short payloads without errors All 15 STORY-144 Red-Gate tests now pass; 135 total tests green; clippy + fmt clean.

…-005/CR-006/CR-007/CR-008/F-144-002 All 135 tests green, clippy -D warnings clean, fmt --check clean. Changes: - CR-001/CR-003/CR-007/CR-008: Remove all stale "not yet implemented" / "RED GATE" / "MUST FAIL" / "against the stub" comments from src/analyzer/tls.rs and tests/tls_analyzer_tests.rs. Grep confirms zero residuals in src/ + tests/. - CR-002: Remove now-redundant #[allow(unused_imports)] on tls_parser import block (parse_tls_message_handshake is actively used by the carry drain loop). - CR-005: Remove #[doc(hidden)] from handshake_reassembly_overflow_count() and rewrite its doc to current-behavior tense. It is a genuine public accessor mirroring truncated_record_count() — not a hidden test seam. - CR-006 (perf): Change record_payload from to_vec() allocation to &record_bytes[5..] borrow. Both .len() and extend_from_slice() accept &[u8]; record_bytes outlives both uses. Also fix clippy::needless_borrow on extend_from_slice call. - F-144-002: Rewrite test_BC_2_07_040_empty_carry_flow_close fixture. Old fixture produced 8 bytes in carry (not empty) because the spoof header was appended after a partial record and the Step-1 guard (carry+payload > MAX_BUF) never fired. New fixture: deliver a single body_len=65537 record so Decision-4 fires immediately (carry starts empty, 4 bytes appended, drain loop sees body_len > MAX_BUF → clear, overflows+1, carry back to 0). Then on_flow_close verifies no errors/findings/flows. Test now genuinely exercises BC-2.07.040 empty-carry-at-close sub-case.

… + regression test SEC-001 (HIGH, CWE-400/834) — quadratic CPU amplification fix: Replace per-message Vec::drain(..k) in the ClientToServer carry drain loop with a cursor-based approach. A local `consumed` usize offset advances `4 + body_len` per consumed message; a single `carry.drain(..consumed)` fires after the loop exits. Total drain cost is O(carry_len) per on_data call instead of O(carry_len^2). The previous O(N*L) approach allowed an attacker to pack ~4,500 zero-body-length messages into one MAX_RECORD_PAYLOAD=18,432-byte record, causing ~40 MB of memmove per on_data call. Semantics preserved: - Decision-4 body_len-spoof guard: carry.clear() + overflows+1 + break (unchanged). - Decision-5 pre-append overflow guard: unchanged. - Exact-consume: each message advances cursor by exactly 4 + body_len regardless of parse outcome (BC-2.07.038 Postcondition 4 / Invariant 2). - Clone-on-dispatch: only msg_type==0x01 allocates message bytes; non-dispatched types (non-0x01) advance the cursor with zero heap allocation. SEC-003 (LOW, CWE-190) — overflow-checks=true safety: Both handshake_reassembly_overflows increment sites (Decision-4 and Decision-5) now use saturating_add(1) instead of bare `+=`. The release profile sets overflow-checks=true; saturation at u64::MAX is safe and intentional for this diagnostic counter. parse_errors left with bare `+=` to match the existing convention. Frame A assertion (adversary LOW): test_BC_2_07_038_canonical_frame_rfc8446_s4: add explicit parse_errors==1 assertion after Frame A delivery per BC-2.07.038 AC-CANONICAL-FRAME. Previously only client_hello_seen==false was asserted at this point. SEC-001 regression test (new): test_BC_2_07_042_coalesced_zero_len_no_quadratic_drain: delivers 1,000 zero-body-length non-0x01 messages in a single 0x16 record. Asserts carry==0, parse_errors==0, overflow_count==0, client_hello_seen==false. Guards against reintroducing O(N^2) drain. Custom CSS: none. All code changes use existing patterns. All 16 story_144 tests pass; full suite green (0 failures); clippy clean; fmt clean.

Records the AFTER half of the before/after pair for the TLS carry buffer and ClientHello fragmentation reassembly fix. Recordings cover: - AC-144-002-reassembly-fragmented: fragmented ClientHello now extracts SNI=['example.com'] + JA3 with parse_errors:0 (was MISSED on baseline) - AC-144-002-control-regression: single-record control pcap still works - AC-144-002-before-after-contrast: side-by-side BEFORE/AFTER contrast - AC-144-003-overflow-clear-recover: carry overflow unit tests passing (test_vp039_carry_overflow_clear_and_recover + summarize exposes counter) Baseline: .factory/demo-evidence/fix-tls-clienthello-frag/ (develop at a2d8c13) Fixture pcaps reused from baseline cycle.

Zious11 · 2026-06-30T02:30:53Z

Review Cycle 1 Triage

Finding	Severity	Description	Disposition
NIT-1	NON-BLOCKING	Duplicated overflow-increment site (Decision-5 + Decision-4 both write to handshake_reassembly_overflows; detail map cannot distinguish modes)	Accepted per SEC-005 INFO finding; observability split deferred to future story
NIT-2	NON-BLOCKING	client_hello_seen set before handle_client_hello runs	Pre-existing pattern; drain cursor still advances correctly; behavior correct
NIT-3	NON-BLOCKING	server_hs_carry is dead field this PR	Intentional: STORY-145 scope; field + accessor committed for STORY-145 forward-compat
NIT-4	NON-BLOCKING	Comment accurately documents parse_tls_message_handshake call site	No action needed

Verdict: APPROVE (0 blocking findings)

All 5 ACs verified. 136 tests pass (15 Red-Gate + 1 anti-quadratic + 120 existing). SEC-001 (quadratic drain) and SEC-003 (saturating_add) resolved. Demo evidence present (4 recordings). Carrying to CI gate.

…+146) STORY-144 (TLS carry buffer + ClientHello reassembly) squash-merged via PR #341 (0986e87), 11/11 CI green. Per-story adversarial 3-clean + security pass (SEC-001 quadratic-drain DoS found+fixed) + demo pass (fragmented ClientHello: MISSED→DETECTED). stories_delivered 91→92. Wave 65 DONE. develop HEAD 0986e87. Wave 66 active: STORY-145 (ServerHello symmetry+isolation) first, then STORY-146 (buffer-saturation telemetry) from updated develop. Both dep STORY-144 satisfied. Delivering sequentially (both touch tls.rs). Decisions: D-307 added. Deferred items filed: SEC-002 (narrow overflow window [MAX_BUF-3,MAX_BUF] → F6), done()-mid-loop cross-direction carry (→ wave-gate review, pre-existing), SEC-004 (parse_errors u64 overflow → maintenance sweep, LOW). Count-propagation sweep: stories_delivered updated from 91→92 in: STATE.md frontmatter, STATE.md Notes, STATE.md Project Metadata table. Old develop SHA (ab0b388) removed from frontmatter + Metadata table; historical references in D-301/D-306/D-300 notes preserved as immutable past-state records (accurate).

…STORY-145, closes S2C SNI/JA3S fragmentation gap) (#343) ## Summary STORY-145 extends the TLS handshake-message reassembly carry-buffer mechanism (introduced in STORY-144 for ClientHello/ClientToServer) to the **ServerToClient direction**. A ServerHello fragmented across multiple TLS 0x16 records is now reassembled so JA3S fingerprinting and detection work correctly. This closes the S2C half of the silent SNI/JA3S evasion gap (TLS-CLIENTHELLO-FRAG-001). The ServerToClient carry-drain arm is a byte-for-byte symmetric mirror of the ClientToServer path delivered in STORY-144: - Clear-and-recover on overflow (`MAX_BUF=65536`, per-record limit 18432) - Cursor + single-drain O(carry_len) — DoS-safe (SEC-001) - `saturating_add` aggregates overflows 4 new tests in `mod story_145` (2 AC-cited Red-Gate + 2 DoS-guard sibling-coverage per DF-SIBLING-SWEEP-001). Commits will be squash-merged. --- ## Behavioral Contract Traceability | BC ID | Version | Title | AC Coverage | |-------|---------|-------|------------| | BC-2.07.041 | v1.2 | Handshake Carry Buffers Are Per-Flow and Per-Direction Isolated | AC-145-001, AC-145-002, AC-145-003 | | BC-2.07.002 | v1.6 | Parse Complete TLS ServerHello: JA3S Fingerprint Computed | AC-145-004, AC-145-005 | | BC-2.07.038 | v2.7 | (referenced) Carry buffer overflow, exact-consume, truncation semantics | AC-145-001 (symmetric) | **Verification Property:** VP-039 Sub-E (direction isolation proptest + cross-flow isolation unit test) ```mermaid flowchart LR BC241["BC-2.07.041 v1.2\n(Direction Isolation)"] --> AC1["AC-145-001\nS2C carry drain"] BC241 --> AC2["AC-145-002\nDirection selector"] BC241 --> AC3["AC-145-003\nCross-flow isolation"] BC202["BC-2.07.002 v1.6\n(ServerHello JA3S)"] --> AC4["AC-145-004\nFragmented reassembly"] BC202 --> AC5["AC-145-005\nSingle-record regression"] AC1 --> TEST1["proptest_vp039_direction_isolation"] AC2 --> TEST1 AC3 --> TEST2["test_BC_2_07_041_cross_flow_isolation"] AC4 --> TEST1 AC5 --> TEST3["test_parse_server_hello\n+ CLI smoke"] TEST1 --> IMPL["src/analyzer/tls.rs\nServerToClient arm"] TEST2 --> IMPL TEST3 --> IMPL ``` --- ## Story Dependencies ```mermaid graph LR STORY144["STORY-144\nClientToServer carry\n(merged #341)"] --> STORY145["STORY-145\nServerToClient carry\n(this PR)"] STORY145 -.->|blocks| STORY146["STORY-146\n(future)"] ``` **STORY-144** merged as PR #341 (`feat(analyzer): TLS handshake-message reassembly across records`). This PR depends on STORY-144's struct fields (`server_hs_carry`, `handshake_reassembly_overflows`) and the `ClientToServer` drain loop being in place. --- ## Architecture Changes ```mermaid graph TD subgraph "src/analyzer/tls.rs" TR["try_parse_records()"] TR -->|"Direction::ClientToServer\n0x16 record"| C2S["client_hs_carry\ndrain loop\n(STORY-144)"] TR -->|"Direction::ServerToClient\n0x16 record\nNEW"| S2C["server_hs_carry\ndrain loop\n(STORY-145)"] S2C --> SH["handle_server_hello()\nmsg_type==0x02"] SH --> SSH["server_hello_seen=true\nja3s_counts populated"] S2C --> OVF["Overflow guard:\nclear-and-recover\nMAX_BUF=65536"] end subgraph "TlsFlowState (per-flow, unchanged)" CK["client_hs_carry: Vec<u8>"] SK["server_hs_carry: Vec<u8>"] end subgraph "HashMap<FlowKey, TlsFlowState>" HM["Flow isolation\n(per-flow keying)"] end S2C --> SK C2S --> CK TR --> HM ``` **Files changed:** - `src/analyzer/tls.rs` — +128/-35 lines (ServerToClient 0x16 carry drain path wired) - `tests/tls_analyzer_tests.rs` — +535 lines (4 new tests in `mod story_145`) - `docs/demo-evidence/STORY-145/` — 3 WebM recordings + 3 GIFs + evidence-report.md - `tests/tls_analyzer_tests.proptest-regressions` — 1-byte fragmentation regression seed --- ## Acceptance Criteria → Test → Demo Evidence | AC | BC Traces To | Test | Demo | |----|-------------|------|------| | AC-145-001: S2C carry drain symmetric | BC-2.07.041 v1.2 Inv 2; BC-2.07.038 v2.7 PC3b | `proptest_vp039_direction_isolation` | [AC-001-002-direction-carry-drain.webm](docs/demo-evidence/STORY-145/AC-001-002-direction-carry-drain.webm) | | AC-145-002: Direction selector → no cross-dir bleed | BC-2.07.041 v1.2 Inv 2; PC 1–2 | `proptest_vp039_direction_isolation` | Same as above | | AC-145-003: Cross-flow isolation | BC-2.07.041 v1.2 Inv 1, 4; PC 1, 4–5 | `test_BC_2_07_041_cross_flow_isolation` | [AC-003-cross-flow-isolation.webm](docs/demo-evidence/STORY-145/AC-003-cross-flow-isolation.webm) | | AC-145-004: Fragmented S2C → `server_hello_seen=true` | BC-2.07.002 v1.6 PC7, Inv 4 | `proptest_vp039_direction_isolation` (interleaved) | Covered by AC-001/002 recording | | AC-145-005: Single-record ServerHello regression | BC-2.07.002 v1.6 Inv 4; BC-2.07.038 v2.7 EC-007 | `test_parse_server_hello` + CLI smoke | [AC-005-single-record-regression.webm](docs/demo-evidence/STORY-145/AC-005-single-record-regression.webm) | --- ## Demo Evidence | AC | Shows | Recording | |----|-------|-----------| | AC-145-001/002 | Fragmented ServerHello reassembled; `server_hello_seen=true`, `ja3s_counts` non-empty, `parse_errors=0`, carries drain to 0 | `docs/demo-evidence/STORY-145/AC-001-002-direction-carry-drain.webm` | | AC-145-003 | Two concurrent flows, fragmented ServerHellos, `sni_counts==2`, no cross-flow bleed | `docs/demo-evidence/STORY-145/AC-003-cross-flow-isolation.webm` | | AC-145-005 | Single-record ServerHello regression-free | `docs/demo-evidence/STORY-145/AC-005-single-record-regression.webm` | AC-145-004 (server overflow/spoof guards) covered by `test_vp039_server_carry_overflow_clear_and_recover` and `test_vp039_server_body_len_spoof` unit tests — overflow/error-path tests produce no user-observable CLI output distinguishable from a normal pass. --- ## Test Evidence | Suite | Pass | Fail | Notes | |-------|------|------|-------| | `cargo test --test tls_analyzer_tests story_145` | 4 | 0 | All STORY-145 ACs covered | | `cargo test --all-targets` | 140 | 0 | Full suite including STORY-144 regressions | | `cargo clippy --all-targets -- -D warnings` | CLEAN | 0 | Zero warnings | | `cargo fmt --check` | CLEAN | — | Formatting gate passes | All tests pass locally on stable Rust (Rust 2024 edition, `rust-version = "1.91"`). --- ## Security Review Reviewed by `vsdd-factory:security-reviewer` against PR #343 diff (STORY-145). No CRITICAL or HIGH findings. | ID | Severity | CWE | Finding | Disposition | |----|----------|-----|---------|-------------| | SEC-001 | INFO | CWE-191 | Carry subtraction arithmetic — underflow evaluated | Confirmed sound. Loop invariant guarantees `consumed <= carry_len` at all times. | | SEC-002 | INFO | CWE-125 | `record_bytes[5..]` slice safety | Confirmed safe. `total_record_len = 5 + payload_len` guaranteed by upstream guards. | | SEC-003 | INFO | CWE-190 | `saturating_add` on overflow counter | Correct idiom; prevents panic under `overflow-checks = true`. | | SEC-004 | INFO | CWE-664 | Cross-direction isolation | Structurally enforced by exhaustive `match direction` arms; no cross-contamination path exists. | | SEC-005 | INFO | CWE-668 | Cross-flow isolation | HashMap keying enforces isolation; no global mutable carry state. | | SEC-006 | LOW | CWE-400 | Step-1 guard uses strict `>` — carry can reach exactly MAX_BUF (65,536 bytes) | Pre-existing property of the symmetric design inherited from STORY-144 (ClientToServer arm accepted with same condition). Not a regression. Carry is still bounded. | | SEC-007 | INFO | CWE-668 | Aggregate counters shared across flows | By design; documented. No security exploit path. | **DoS guards confirmed sound:** - Step-1 overflow: clear-and-recover fires when `carry_len_before + record_payload.len() > MAX_BUF (65,536)`. Bounded by per-record cap (`MAX_RECORD_PAYLOAD = 18,432`). - Decision-4 body_len spoof: guard fires when parsed `body_len > MAX_BUF`; clears carry, increments counter, post-loop drain skipped via `decision4_fired` flag. - Incomplete-message guard: `carry_len - consumed < 4 + body_len` — arithmetic safe per SEC-001 analysis. **Overall: APPROVE.** No CRITICAL/HIGH findings. SEC-006 (LOW) is pre-existing symmetric property, not a regression. --- ## Risk Assessment | Dimension | Assessment | |-----------|------------| | Blast radius | Narrow: SS-07 (`src/analyzer/tls.rs`) only. No new struct fields, no new files, no new dependencies. | | Regression risk | Low: ServerToClient drain path was previously a single-record dispatch; new path is a carry-buffer drain that degrades gracefully to single-record fast path on first invocation. 140 existing tests unaffected. | | Performance impact | O(carry_len) drain loop is bounded by `MAX_BUF=65536`. No quadratic growth. `saturating_add` overflow counter is O(1). | | DoS surface | Mitigated: Step-1 overflow guard (clear-and-recover at 65536 bytes) prevents unbounded accumulation. Decision-4 body_len spoof guard prevents false-completion on spoofed length field. | | Security correctness | Positive: closes S2C half of TLS-CLIENTHELLO-FRAG-001 silent evasion gap. Improves detection coverage. | --- ## AI Pipeline Metadata | Field | Value | |-------|-------| | Pipeline mode | Feature (f-sequence) | | Story wave | 66 | | Story phase | f3 (TDD implementation) | | TDD mode | strict | | Model | claude-sonnet-4-6 | | Story points | 5 | | Squash merge | Yes | --- ## Pre-Merge Checklist - [x] PR description populated with traceability - [x] Demo evidence present (3 WebM recordings, evidence-report.md) - [x] All STORY-145 tests pass locally (4/4) - [x] Full test suite passes locally (140/0) - [x] `cargo clippy --all-targets -- -D warnings` clean - [x] `cargo fmt --check` passes - [x] STORY-144 (depends_on) merged as PR #341 - [x] Security review complete (APPROVE — no CRITICAL/HIGH; SEC-006 LOW pre-existing) - [x] PR review approved (pr-reviewer — APPROVE, 0 blocking, 3 non-blocking nits) - [x] CI green — all 11 checks pass (action-pin-gate, audit, clippy, deny, fmt, fuzz-build, green-doc-tense-gate, help-provenance-gate, semantic-PR, test, trust-boundary)

… log SEC-006/dup/doc deferrals STATE.md: - current_step: STORY-145 MERGED, NEXT: STORY-146 - develop_head: 0986e87→d3d2e1989bc9ca5ecfc7b4eb3d3fa9fd80dccaa2 - stories_delivered: 92→93 - story_index_version: v3.6→v3.7 - story_index_note: STORY-145 MERGED wave 66 PR #343 d3d2e19; STORY-146 pending - Open worktrees: removed story-145 ACTIVE line (worktree removed) - EXACT RESUME POINT: rewritten to wave-66 STORY-146 NOT STARTED - RESUME PROCEDURE: updated to develop d3d2e19, new worktree creation for STORY-146 - Project Metadata table: develop HEAD + stories count updated - Phase Progress F4 row: STORY-145 MERGED - Current Phase Steps: added DONE row for STORY-145 TDD delivery; NEXT→STORY-146 - Decisions Log: added D-309 (STORY-145 MERGED PR #343, convergence, CI, human merge) - Open Items: TLS-CLIENTHELLO-FRAG-001 status updated; added SEC-006/TLS-DRAIN-DUP-001/TLS-STALE-COMMENT-001 - Session Resume Checkpoint: updated to STORY-145 MERGED; STORY-146 next - Notes footer: updated story-index version, develop HEAD, STORY-145 MERGED stories/STORY-145.md: - status: draft→merged (v1.1 doc already in place; input-hash 88e29c9 MATCH) stories/STORY-INDEX.md: - version: 3.6→3.7; timestamp updated - v3.7 changelog entry added - STORY-144 status: draft→merged (wave 65 PR #341 0986e87) - STORY-145 status: draft→merged (wave 66 PR #343 d3d2e19) - Wave 65 delivery row: DELIVERED & CLOSED #341 0986e87 2026-06-29 - Wave 66 delivery row: STORY-145 DELIVERED #343 d3d2e19; STORY-146 pending Count-propagation sweep: stories_delivered 92→93 updated in STATE.md frontmatter, metadata table, Notes footer, and STORY-INDEX changelog. Old count (92) remains only in immutable historical rows (D-307 past decision, 91→92 arrow-notation in step history) — intentional.

Zious11 added 6 commits June 29, 2026 19:47

Zious11 enabled auto-merge (squash) June 30, 2026 02:33

Merge branch 'develop' into feature/story-144-tls-carry-reassembly

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Zious11 merged commit 0986e87 into develop Jun 30, 2026
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Zious11 deleted the feature/story-144-tls-carry-reassembly branch June 30, 2026 02:36

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feat(analyzer): TLS ServerHello handshake reassembly across records (STORY-145, closes S2C SNI/JA3S fragmentation gap) #343

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feat(analyzer): TLS buffer-saturation telemetry — buffer_saturation_drops counter (STORY-146) #344

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feat(analyzer): TLS handshake-message reassembly across records (STORY-144, closes SNI/JA3 fragmentation evasion)#341

feat(analyzer): TLS handshake-message reassembly across records (STORY-144, closes SNI/JA3 fragmentation evasion)#341
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Zious11 commented Jun 30, 2026

Summary

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Headline: Before / After (AC-144-002)

AC-144-002: Fragmented ClientHello Reassembly

AC-144-002: Single-Record Regression (Control)

AC-144-003: Carry Overflow Clear-and-Recover

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