Fenrir fixes 2026 10 01

[danielinux]

fe18fb4 F-14492: compare bind claims, not resolved egress IPs, in the port-conflict check
b8f5ba1 F-14494: resolve the ICMP connect target before the bound-address check
974a47f F-14493: wildcard-bound sockets source from the egress interface
9d9bd9b F-14497: log wc_AesGcmEncrypt, not wc_AesGcmDecrypt, on encrypt failure
ba4f5ce F-14496: drop the dead second closed-socket guard in tcp_process_ts
29ce82f F-14491: stop flush_tcp_tx from walking the stale cursor after a pop
edfcccf F-14490: clear is_listener when the filter vetoes listen()
bd6f4a2 F-14489: skip DAD when a renew/rebind ACK keeps the in-use IP
de9ac85 F-14519: probe and time out window-blocked teardown sockets
a42f149 F-14518: retransmit the FIN and time out in TCP_CLOSING

[Copilot]

Copilot review overview

🟡 Changes recommended

TCP persist handling can stall teardown sockets and mishandle nonzero sub-segment receive windows.

Review effort: Balanced
Findings: 1 · 3

Open (4)

• Handle TCP_CLOSING when stopping persist timer · New
• Fix persist probing for windows smaller than the segment · New
• Allow DHCP rebind ACKs from a different server · New
• Keep persist armed until the head segment fits · New

What changed in this PR

Fixes TCP teardown/persist behavior, DHCP renewal handling, listener cleanup, and stale FIFO traversal.

Changes:

• Improves TCP teardown retransmission, persist probing, and timeout handling.
• Skips redundant DHCP DAD and clears rejected listener state.
• Adds regression tests and documents unsupported TCP urgent data.

File	Description
src/​wolfip.c	Implements TCP, DHCP, listener, and FIFO fixes.
src/​test/​unit/​unit.c	Registers new regression tests.
src/​test/​unit/​unit_tests_tcp_flow.c	Tests stale FIFO cursor handling.
src/​test/​unit/​unit_tests_proto.c	Tests TCP persist behavior.
src/​test/​unit/​unit_tests_dns_dhcp.c	Tests listener and CLOSING behavior.
src/​test/​unit/​unit_tests_dhcp_edges.c	Tests DHCP renewal/rebinding DAD behavior.
docs/​rfc9293-scope.md	Documents unsupported TCP urgent data.

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[Copilot]

Copilot review overview

🟡 Changes recommended

TCP wildcard ephemeral allocation can still create port conflicts, and rebinding accepts malformed DHCPNAKs without a server identifier.

Review effort: Balanced
Findings: 1 · 1

Open (2)

• Preserve wildcard bind claims during TCP ephemeral port allocation · New
• Reject DHCPNAK messages missing the server identifier · New

Resolved since last review (4)

• Handle TCP_CLOSING when stopping persist timer
• Keep persist armed until the head segment fits
• Allow DHCP rebind ACKs from a different server
• Fix persist probing for windows smaller than the segment

[Copilot]

Copilot review overview

🟡 Changes recommended

Nonzero-window persist probes can advance acknowledgments without retiring queued data, leaving TCP transmission permanently blocked.

Review effort: Balanced
Findings: 1

Open (1)

• Regression test explanation uses the wrong endpoint address · New

Resolved since last review (2)

• Preserve wildcard bind claims during TCP ephemeral port allocation
• Reject DHCPNAK messages missing the server identifier

Previously missed (4)

In code that hasn't changed since last review

Stale local IP used when interfaces have no address

src/​wolfip.c:8020

If neither the routed interface nor the primary interface currently has an address, this branch leaves local_ip at its previous value. A wildcard/unbound ICMP socket that previously sent through another interface will then transmit with that stale source address instead of reflecting the current egress state.

Persist timer is not reset when entering teardown

src/​wolfip.c:8919

Resetting only the retry count does not create the documented fresh ~183-second teardown budget: an already-active persist timer retains its established-state deadline and backoff (up to 60 seconds), so eight teardown probes can take up to 480 seconds. Reset and re-arm active persist state when entering teardown.

LAST_ACK retains inherited persist timer backoff

src/​wolfip.c:8945

The same inherited-backoff problem applies to the LAST_ACK transition: resetting persist_retries leaves an active timer at its old deadline and persist_backoff, extending the nominal three-minute teardown budget to as much as eight minutes.

Incorrect RFC cited for IPv4 address-conflict detection

src/​test/​unit/​unit_tests_dhcp_edges.c:1440

RFC 4331 concerns WebDAV quota properties; IPv4 address-conflict detection is specified by RFC 5227, which the changed implementation correctly cites.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #183

Scan targets checked: wolfip-src, wolfip-bugs
Coverage: 1 of 2 in-scope changed file(s) opened by the reviewer; not opened: src/wolfesp.c

Fenrir result: Approved ✅

No new issues found in the changed files.

Advisory only — this automated result does not count as a GitHub approval.

Review tier: Lite