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Fix: Refuse private destinations at the forward proxy dial (403 destination_private) - #1539
Implements #1484 — the SSRF guard for the forward proxy's outbound dials.
What it does
When listener.egress_guard.enabled: true, every destination the forward
proxy dials is resolved once, checked, and dialed at the checked address:
Refused with 403 destination_private when the address is loopback,
link-local (including the cloud metadata address 169.254.169.254),
RFC 1918 / unique-local space, or one of this host's own interface
addresses, and no permit_cidrs prefix covers it.
Link-local, unspecified and multicast are never permitted, whatever permit_cidrs says — 0.0.0.0 reaches loopback on every mainstream
stack, and the metadata range is what this guard exists among other
things to protect. The moca conformance case pins this: a permit of 0.0.0.0/0 does not open 169.254.169.254.
Literal IPs are checked too — no resolution step is needed to be
tricked, and none is needed to be safe.
permit_cidrs covers prefixes within the refused space (loopback and
RFC 1918 / unique-local are permit-able): 127.0.0.1/32 for a laptop
proxy with a local model, 10.0.0.0/8 for an in-cluster deployment.
Off by default. A sidecar's ordinary upstreams — Keycloak, in-cluster
services, a laptop's local model — live in exactly the refused space, so
defaulting this on would break every existing deployment. The MOCA-shaped
config enables it.
The issue's design question: where in the dial path
One guard, under every dial site, so no path becomes the bypass:
Dial site
Where the check runs
Plain HTTP requests
the transport's DialContext (wired via NewServer's new WithEgressGuard option — the constructor signature is unchanged)
Bridged HTTPS requests
the TLS bridge's re-origination client, via the new tlsbridge.WithDialContext — a refused destination never gets a re-originated request
Under mTLS
inside the mTLS dialer, before the TCP connect, so the TLS handshake never reaches a refused address; SNI still follows the name the request used
CONNECT tunnels
handleConnect, before the dial; the bridge fall-open re-dial reuses the checked address rather than re-resolving
Transparent redirects
HandleTransparentConn, over the SO_ORIGINAL_DST literal; a refusal is recorded (synthetic 403 close row) but never sent — that path speaks no HTTP to the client
skip_hosts traffic
guarded like everything else — a bypass must not become an SSRF bypass; a matched destination is refused with no rows, exactly as its other exceptions are
DNS rebinding: resolve once, dial the checked address
The window the guard closes is between the check and the dial — check
one address, dial another. The fix is to commit to one answer and dial it
verbatim: CheckAddr returns the address it checked (the literal, or the
first resolved answer), and every dial site dials that string, never the
original host. A second resolution has no window to change either. The
moca dns_rebinding_resolved_once shape — a name answering 127.0.0.1
then 10.0.0.9, with only 127.0.0.1/32 permitted — tunnels to 127.0.0.1 with exactly one lookup; the unit tests pin the lookup count
against a counting stub resolver.
Observability
A refused CONNECT leaves its two tunnel rows with tunnelReason: "dest-private" and a 403 close carrying error.kind: "destination_private" — never confused with dial-failed, which attempted.
A refused request leaves an ordinary response row with the same error
kind. Like the 426 upgrade_declined, the Finisher sees an allow with
the status (the guard did what it was configured to), and /v1/usage
does not count it as an error.
A permitted tunnel's open row carries the new dialAddr field — the
checked address that was dialed, the audit trail pairing the name the
client asked for with the address the proxy reached. On the wire as dialAddr (omitempty, so a proxy with the guard off emits nothing
new); SessionEvent.DialAddr rides the usual round-trip/wire-skew test
discipline.
destination_private is the MOCA egress contract's identifier, used
verbatim (as plaintext_credential was in #1481) so the shared conformance
suite matches without a translation table.
A listener.* field, so it inherits the restart-on-reload rule
automatically (validateReloadable compares the whole block).
Tests
core/listener/egressguard: the refusal set table (loopback, metadata,
fe80::, fc00::, 0.0.0.0, multicast, v4-mapped), never-permitted under
blanket permits, permits opening covered space, resolve-exactly-once
with a counting stub, first-answer-rules, errors.As through a *url.Error wrapper, DialContext landing on the first checked answer.
core/listener/forwardproxy: the three moca shapes end to end —
CONNECT and GET to loopback → 403, upstream never dialed, both rows
recorded; metadata refused under 0.0.0.0/0; permitted loopback
tunnels with dialAddr on the open row; and the off-by-default
compatibility contract (no guard → tunnels exactly as before).
core/config: off without the block, on with it, explicit false.
core/sessionapi: the summarize-shape guard count, with the
timeline-vs-detail decision recorded (kept — a scalar, the struct copy
carries it).
Docs: framework-architecture.md (new listener.egress_guard section), session-api.md (dialAddr, the error kind, the tunnel reason), CLAUDE.md event-schema bullets.
Arms an opt-in SSRF dial guard on every outbound dial the forward proxy
makes: CONNECT tunnels, plain and bridged requests, transparent redirects,
and skip_hosts traffic too — a bypass must not become an SSRF bypass. Each
destination is resolved once, refused with 403 destination_private when the
address is loopback, link-local (including 169.254.169.254), RFC 1918 /
unique-local space, or one of this host's own interface addresses and no
permit covers it, and then dialed at the checked address, so DNS rebinding
cannot re-answer between the check and the connect. Link-local, unspecified
and multicast addresses are never permitted, whatever permit_cidrs says.
Off by default: a sidecar's ordinary upstreams — Keycloak, in-cluster
services, a laptop's local model — live in exactly the refused space, so
defaulting this on would break every existing deployment.
- core/listener/egressguard: the guard itself (CheckAddr / DialContext /
DialTimeout, typed Refusal), resolver injectable so the tests pin the
resolve-once property against a counting stub
- forwardproxy: WithEgressGuard option (NewServer signature unchanged);
under mTLS the guard sits inside the dialer so a refused address never
gets a TLS ClientHello; handleConnect and the transparent listener check
before the dial and reuse the checked address for the bridge fall-open
re-dial; serveOutbound renders a Refusal as the listener's standard 403
rejection with error.kind destination_private
- pipeline: SessionEvent.DialAddr on the wire (dialAddr, omitempty) — the
audit trail pairing the name the client asked for with the address
dialed; new tunnelReason "dest-private" (within agentop's 18-char PLUGIN
column cap)
- tlsbridge: WithDialContext so the bridge's re-origination client dials
through the guard — the bridge must not become the path around it
- config: listener.egress_guard {enabled, permit_cidrs}; a listener.*
field, so it inherits the restart-on-reload rule
The moca conformance shapes are pinned by tests: private_address_403
(CONNECT and GET to loopback, upstream never dialed),
metadata_address_403_even_if_permitted (169.254.169.254 under 0.0.0.0/0),
and the rebinding case's Cortex half — resolve exactly once, dial the
first checked answer, open row carries dialAddr.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
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CLAUDE.md
core/listener/egressguard/guard.go
core/listener/egressguard/guard_test.go
core/listener/forwardproxy/egressguard_test.go
core/listener/forwardproxy/server.go
core/listener/forwardproxy/transparent.go
core/pipeline/context.go
core/pipeline/session.go
core/pipeline/session_test.go
core/sessionapi/summary_test.go
docs/session-api.md
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Walkthrough
The change adds an optional egress guard for outbound proxy destinations. It checks destinations before dialing, returns 403 destination_private for refused destinations, and records checked dial addresses on guarded tunnel-open events. Destination-private refusals remain in request counts but do not count as usage errors.
Changes: Egress Guard
Layer / File(s)
Summary
Guard configuration and address checks core/config/config.go, core/config/config_test.go, core/listener/egressguard/*
Listener configuration adds egress_guard and permit_cidrs. The guard resolves hostnames once, checks the first address, applies refusal and permit rules, and returns the checked dial address or a refusal.
Guarded proxy and bridge dialing cmd/cortex/main.go, core/listener/forwardproxy/*, core/tlsbridge/upstream.go
Startup passes the guard to the forward proxy and TLS bridge. Forwarded requests, CONNECT tunnels, and transparent connections check destinations before dialing and reuse the checked address for fallback dials.
Session events add destination-private refusal and optional dialAddr data. Usage excludes destination-private refusals from error counts. The control-rune sanitizer is exported and used for client-controlled values.
Configuration and event documentation CLAUDE.md, docs/framework-architecture.md, docs/session-api.md
rossoctl/cortex#1462 — This change extends the existing upgrade_declined usage classification pattern to destination_private.
rossoctl/cortex#1467 — This change applies egress checks to CONNECT and TLS-bridge upstream dialing paths.
rossoctl/cortex#1534 — This change adds a distinct destination_private refusal outcome alongside failed CONNECT tunnel dials.
Suggested labels:ready-for-ai-review
Suggested reviewers:huang195
Merge Risk: Minimal · up to 3873b
The reported guard bypass and incorrect refusal outcome have been corrected. No actionable merge-blocking risk remains in the supplied evidence.
Pre-merge checks: 5
Check name
Status
Explanation
Description Check
Check skipped - CodeRabbit’s high-level summary is enabled.
Title check
The title clearly and concisely identifies the main change: refusing private destinations at the forward-proxy dial with a 403 destination_private response.
Linked Issues check
Requirements from #1484 are coding requirements. The reviewed head meets them.
[Resolve once, check, dial the checked address] core/listener/egressguard/guard.goCheckAddr calls the resolver once…
Out of Scope Changes check
Most changed areas connect directly to #1484. These include egressguard (guard, tests), forwardproxy (server, transparent, tests), tlsbridge (WithDialContext), config (EgressGuardConfig), …
Docstring Coverage
Docstring coverage is 90.48% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentati…
Full details: Linked Issues check
Explanation
Requirements from #1484 are coding requirements. The reviewed head meets them.
[Resolve once, check, dial the checked address] core/listener/egressguard/guard.goCheckAddr calls the resolver once. It checks the first answer, or the literal when the request names an IP. CheckAddr returns netip.AddrPortFrom(dialAddr, port). DialContext dials that returned string, not the host name. The tests TestCheckAddr_ResolvesOnceAndDialsFirstChecked and TestCheckAddr_FirstAnswerRules cover this behavior.
[Refuse private, loopback, link-local, unique-local and host-owned addresses with 403 destination_private] check, refusable and hostOwns cover loopback, RFC 1918 and unique-local space, and the host's own interface addresses. The Refusal type maps to destination_private. Forward-proxy tests TestForwardProxy_EgressGuardRefusesLoopbackCONNECT and TestForwardProxy_EgressGuardRefusesPrivateGET cover the 403 responses and the upstream-not-dialed property.
[Metadata refused even when permitted] neverPermitted refuses 169.254.0.0/16 (link-local unicast), fd00:ec2::254, unspecified and multicast addresses before any permit check. TestForwardProxy_EgressGuardMetadataEvenIfPermitted covers a 0.0.0.0/0 permit.
[Literal IPs checked] A literal host parses through netip.ParseAddr and passes through the same check path.
[Tunnels, bridged HTTPS, mTLS and transparent paths dial the checked address] The reviewed summary reports these wiring points: WithEgressGuard in forwardproxy/server.go, tlsbridge.WithDialContext in tlsbridge/upstream.go, and the checked address in transparent.go. Dial-path behavior is supported by the summary and the forward-proxy tests. I did not re-read those files in this review.
[Audit dial_addr] SessionEvent.DialAddr (dialAddr, omitempty) is set on permitted tunnel-open rows. The issue names dial_addr for the DNS-rebinding case, and the summary indicates the CONNECT path carries it. The summary does not confirm that plain HTTP rows carry it. The moca conformance suite was not run here.
[Follow-up fixes] The IPv6 zone is stripped for the check and kept for the dial (checkAddr := dialAddr.WithZone("")). TestCheckAddr_ZonedV6DoesNotEscapeHostOwned covers this. The transparent 403 status fix is covered by TestTransparent_EgressGuardRefusalReportsAnAllowToFinishers.
Unresolved: the three conformance suite cases named in the issue are external to this repository. Conformance is inferred from the equivalent unit and forward-proxy tests.
Full details: Out of Scope Changes check
Explanation
Most changed areas connect directly to #1484. These include egressguard (guard, tests), forwardproxy (server, transparent, tests), tlsbridge (WithDialContext), config (EgressGuardConfig), pipeline/session.go (DialAddr, TunnelDestPrivate, ErrorKindDestinationPrivate), pipeline/context.go (DialedAddr), cost/usage (refusals not counted as errors), sessionapi guard count, and the documentation.
One change lacks a stated link to the guard. In core/pipeline/context.go, RecordStrippedUpgrade now calls the renamed exported helper SanitizeControlRunes in place of sanitizeUA. The rename is shown in core/pipeline/client.go. The PR description does not mention it. The change keeps behavior the same, so it does not alter the egress guard. It is a small, behavior-preserving refactor. I did not confirm whether a guard path calls the exported helper. No unrelated behavior change is demonstrated.
Full details: Docstring Coverage
Explanation
Docstring coverage is 90.48% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 42 functions across 16 files. (2 skipped: 2 unsupported.)
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Self-review of #1539, both accuracy rather than behavior:
- SessionEvent.DialAddr's comment claimed the field is absent "on events
that dialed nothing", but a guarded plain or bridged request dials
through the guarded transport and records no dialAddr either — only a
tunnel's open row carries it. Say that instead: present only on a
tunnel's open row, absent when the guard is off. session-api.md already
said exactly this.
- The "egress guard on" boot log fired wherever the guard was configured,
including a reverse-only deployment where no forward proxy exists to
enforce it. The guard is still built before the TLS bridge (the bridge's
re-origination client consumes it), but the announcement now logs in the
forward-role block, where it is true.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
#1484)
CodeQL on #1539 flagged "Log entries created from user input" at the
serveOutbound refusal Debug: r.Host and r.Method are client-controlled,
and a control rune forged into either would forge a log entry — the same
CWE-150 shape the User-Agent path already guards against.
- Rename pipeline.sanitizeUA to pipeline.SanitizeControlRunes. The rule
(C0/DEL/C1/bidi/zero-width and invalid UTF-8 replaced with U+FFFD) and
its rationale are unchanged; only the name now says what it is: the
rule applies to any client-controlled string headed for a surface a
terminal or a file renders, not only a User-Agent. Exported so the
listeners can use the one copy rather than grow a third loop beside
the ledger's sanitizeLabel.
- Apply it at every log site this PR added: the serveOutbound refusal
Debug (Host, Method), handleConnect's refusal Warn (Host) and
resolution-failure Warn (Host and the error string, which embeds the
name via net.DNSError), and the transparent listener's refusal Warn
(host — sniffed off the client's own bytes as SNI or a Host header).
Values that are not client-controlled — the guard's parsed address,
the kernel's SO_ORIGINAL_DST literal — stay raw.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
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The design holds up. One guard sits under every dial site, the checked address is the one that gets dialed, the fall-open re-dials reuse it, and skip_hosts traffic is guarded too. I checked each dial site in core/listener and core/tlsbridge and found no unguarded path.
Two things don't do what the PR says, and I confirmed both with throwaway tests at 2a3cc17:
/v1/usage does count the refusal as an error.countsAsError(403 destination_private) returns true, because core/cost/usage/usage.go only exempts upgrade_declined. CLAUDE.md, docs/session-api.md, docs/framework-architecture.md and the ErrorKindDestinationPrivate comment all say it does not.
The "host's own addresses" check refuses the host's whole subnet. It tests against the interface's prefix, not its address. On my laptop that refuses all of 9.67.64.0/18, which is public space, plus every LAN neighbour. Details inline.
The rest are suggestions and nits.
Author: mrsabath (MEMBER — maintainer) Areas reviewed: Go (core/listener, egressguard, tlsbridge, pipeline, config, cost/usage), docs Agent/IDE config (.claude/.vscode): none Commits: 3 commits, all signed-off: yes CI status: passing
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must-fix: This is not true yet. countsAsError in core/cost/usage/usage.go:1273 only exempts ErrorKindUpgradeDeclined. A 403 with Kind: destination_private has StatusCode >= 400, so it is counted. I checked with a scratch test in package usage: countsAsError(&SessionEvent{StatusCode: 403, Error: &EventError{Kind: ErrorKindDestinationPrivate}}) returns true.
The same claim is in CLAUDE.md's event-schema bullet, docs/session-api.md and docs/framework-architecture.md. Please add the kind to countsAsError, with a test next to the upgrade_declined one. Or, if counting it is what you want, change the four docs.
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Fixed in b3dcd1f. countsAsError now exempts ErrorKindDestinationPrivate alongside upgrade_declined, with TestRecord_DestinationPrivateIsNotAnError next to the declined-upgrade test pinning that an origin's own 403 still counts — the exemption is the kind, not the status. You were right that the docs were the contract and the code was wrong; thank you for the scratch test, it made this a two-minute fix instead of an argument.
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must-fix: net.InterfaceAddrs() returns ip/mask (for example 192.168.1.167/24), so prefix.Contains(ip) matches the interface's whole subnet, not just the host's address.
I probed this on my laptop. With interfaces 192.168.1.167/24 and 9.67.123.175/18, refusable returned true for 192.168.1.1 and for 9.67.64.1. That second one is public address space, but every destination in that /18 gets 403 destination_private. On a cloud VM with a public address on a large on-link prefix, this refuses ordinary public upstreams. Nothing in permit_cidrs' documentation tells an operator they would need to permit public space.
The doc comment and the docs say "one of this host's own interface addresses". If that's the rule, use prefix.Addr() == ip. If refusing the subnet is intended, the docs should say so, and the test table should pin it.
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Fixed in b3dcd1f — and this was the more serious of the two, thank you for probing it on real interfaces. hostOwns now compares the interface's address itself (prefix.Addr() == ip), not the on-link prefix. TestHostOwns pins the distinction with your exact probes: 9.67.64.1 and 192.168.1.1 pass, 9.67.123.175 itself is refused. The fail-closed on InterfaceAddrs error is unchanged.
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suggestion: Some metadata and loopback-reaching addresses get past this set:
AWS IMDS over IPv6 is fd00:ec2::254. That is ULA, not link-local, so it lands in the permit-able set. permit_cidrs: ["fd00::/8"] opens it (I checked: CheckAddr returns nil). So "the metadata range is never permitted" only holds for IPv4.
100.64.0.0/10 (CGNAT) isn't refused at all. Alibaba Cloud's metadata service is 100.100.100.200, and CheckAddr passes it.
NAT64 64:ff9b::/96: [64:ff9b::7f00:1] (which embeds 127.0.0.1) passes. That matters on a NAT64 host.
At minimum, I'd add fd00:ec2::254/128 to the never-permitted case. Whether the other two belong in the refused set is your call. Either way, please name them in the package comment so the boundary is explicit.
fd00:ec2::254 is never-permitted — you're right that "never" only held for IPv4, and a fd00::/8 permit is plausible enough to have opened it. Pinned in TestCheckAddr_NeverPermitted.
100.64.0.0/10 is refused like private space and permit-able like it (Alibaba's 100.100.100.200 refused by default, open under a covering permit) — TestCheckAddr_RefusedRanges / TestCheckAddr_CGNATPermittable.
NAT64 64:ff9b::/96 is checked by the IPv4 it embeds ([64:ff9b::7f00:1] refused as the 127.0.0.1 it carries, [64:ff9b::a9fe:a9fe] as 169.254.169.254), while the v6 form stays the dial target since the bare v4 may not route on a NAT64 host. The mapping is arithmetic, not a lookup, so checking one form and dialing the other opens no check-vs-dial window. TestCheckAddr_NAT64CheckedByEmbeddedV4.
All three are named in the package comment, the config docs and framework-architecture.md.
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nit: DialTimeout has no caller. The CONNECT and transparent paths call CheckAddr and then net.DialTimeout themselves, because they need the checked address for DialedAddr and the fall-open re-dial. I'd delete it.
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nit: A service-name port (CONNECT example.com:https) used to dial, because net.DialTimeout resolves service names. Now it fails here with strconv.ParseUint: parsing "https" and returns a 502. Also, this parse runs after the DNS lookup, so a bad port still costs a resolution. net.LookupPort(network, port) before the resolve would fix both.
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Fixed in b3dcd1f. The port is now parsed with net.LookupPortbefore the resolve, which accepts both numbers and service names, so example.com:https dials again instead of 502ing, and a bad port costs no DNS lookup. TestCheckAddr_ServiceNamePort pins both — including lookups == 0 on the bad-port path.
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nit: The new paragraph is appended under the old sanitizeUA doc block. As a result, godoc for SanitizeControlRunes opens with "sanitizeUA replaces every control character…", a function that no longer exists. About seven other comments still say sanitizeUA (client.go:47, 166, 238, 451, 464, 471, and context.go:479). A sed over those plus moving this paragraph to the top of the block would keep it readable.
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Fixed in b3dcd1f. The rename paragraph now leads the doc block, so godoc opens with SanitizeControlRunes replaces every control character in s with U+FFFD (and one line saying where the rule lived before, since that history is why the export is safe to build on). The seven other comment references follow the new name.
Hai's review of #1539, all six findings:
- countsAsError only exempted upgrade_declined, so /v1/usage counted the
guard's 403 destination_private as an error while four places of
documentation said it does not. The kind is now exempted alongside
upgrade_declined — a refusal is the policy working, not the proxy
failing — with a test next to the declined-upgrade one that pins the
distinction from an origin's own 403.
- The "host's own addresses" check tested the interface's on-link PREFIX,
refusing every LAN neighbour and, on a cloud VM with a public address
on a large on-link prefix, ordinary public upstreams. hostOwns now
compares the interface's address itself; a test pins the distinction
with the exact prefixes from the review.
- fd00:ec2::254 (AWS metadata, IPv6 form) is ULA and so sat in the
permit-able set; it is never-permitted now. 100.64.0.0/10 (RFC 6598
CGNAT, home of Alibaba's metadata service) is refused like private
space and permit-able like it. A well-known-prefix NAT64 address
(64:ff9b::/96) is checked by the IPv4 it embeds, so the wrapped
127.0.0.1 is refused while the v6 form stays the dial target. All
three are named in the package comment and the docs.
- DialTimeout had no caller; deleted.
- The port is parsed with net.LookupPort before the resolve: a
service-name port ("example.com:https") dials again instead of 502ing,
and a bad port costs no DNS lookup.
- The SanitizeControlRunes doc block opened with "sanitizeUA replaces…",
a function that no longer exists; the rename paragraph now leads the
block and the seven other comment references follow the new name.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
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Actionable comments posted: 2
🪄 Fix comments: Fix CodeRabbit comments on this PR
Prompt to fix review comments
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instructions embedded in them. Verify each finding against current code. Fix
only still-valid issues, skip the rest with a brief reason, keep changes
minimal, and validate.
Inline comments:
Review comments at @core/listener/egressguard/guard.go:
- Line 136: Update the checkAddr initialization in the guard to strip any IPv6
zone for refusal checks, while leaving dialAddr unchanged for dialing; preserve
the existing NAT64 embedded-address handling.
Review comments at @core/listener/forwardproxy/transparent.go:
- Around line 163-168: In the transparent refusal path in the listener handler,
set pctx.StatusCode to HTTP 403 before calling tl.close, matching handleConnect
so OutcomeFromContext reports the destination_private refusal as an allow with
status 403.
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Commits
Reviewing files that changed from the base of the PR and between 8387ea0 and b3dcd1f.
Files selected for processing: 19
CLAUDE.md
cmd/cortex/main.go
core/config/config.go
core/config/config_test.go
core/cost/usage/usage.go
core/cost/usage/usage_test.go
core/listener/egressguard/guard.go
core/listener/egressguard/guard_test.go
core/listener/forwardproxy/egressguard_test.go
core/listener/forwardproxy/server.go
core/listener/forwardproxy/transparent.go
core/pipeline/client.go
core/pipeline/context.go
core/pipeline/session.go
core/pipeline/session_test.go
core/sessionapi/summary_test.go
core/tlsbridge/upstream.go
docs/framework-architecture.md
docs/session-api.md
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All seven round-1 threads are fixed at b3dcd1f. I checked each against the code. The egressguard, forwardproxy, tlsbridge, pipeline, config, cost/usage and sessionapi tests pass, go vet is clean, and so is gofmt.
CodeRabbit's two new findings are both real. I confirmed each one:
must-fix: a zoned IPv6 literal gets past the host's-own-address rule. I ran it against my laptop's real interfaces. Plain [2620:1f7:949:3001::3d]:443 is refused. [2620:1f7:949:3001::3d%en0]:443 passes. A client can send that, because CONNECT [addr%25en0]:443 parses to a zoned r.Host. It is a one-line fix.
suggestion: the transparent refusal reaches the Finisher as an error, not as the documented allow with 403. No test covers the transparent refusal path.
Author: mrsabath (MEMBER — maintainer) Areas reviewed: Go (egressguard, forwardproxy, transparent, cost/usage, config), docs Agent/IDE config (.claude/.vscode): none Commits: 4 commits, all signed-off: yes CI status: passing
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must-fix: CodeRabbit's zone finding is real. I checked it on real interfaces with a scratch test. For each of my laptop's global IPv6 addresses, CheckAddr("tcp", "[<own>]:443") returns the Refusal, and CheckAddr("tcp", "[<own>%en0]:443") returns [<own>%en0]:443 with no error. hostOwns compares with ==, and that includes the zone. A client can deliver one: CONNECT [2001:db8::5%25en0]:443 parses to r.Host = "[2001:db8::5%en0]:443", and a GET's URL host does the same.
The gap is narrow. It covers only the host's own public addresses, because link-local, loopback and private space are refused by the other checks whatever the zone. It is still a bypass of a rule the docs promise. checkAddr := dialAddr.WithZone("") closes it, and the dial can keep the zone. Please add a zoned row to TestHostOwns, or to the CheckAddr table.
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suggestion: CodeRabbit is right here too. handleConnect sets pctx.StatusCode = http.StatusForbidden before it records the refusal (server.go:2298). This path never sets pctx.StatusCode anywhere. The deferred RunFinish therefore gets OutcomeFromContext → StatusCode == 0 → OutcomeError, and the PR body and CLAUDE.md say a refusal is an allow with 403. Set it here, the same way.
No test covers this branch either: egressguard_test.go exercises CONNECT and GET but never HandleTransparentConn. One case that asserts the 403 close row and the Finisher's outcome would pin both.
Three conflicts, all additive — main and this branch each appended to the same
event-schema prose and the same projection count.
- `core/sessionapi/summary_test.go`: main added `Ttfb` (#1251) and this branch
added `DialAddr`, each as the 29th kept field. Both are kept, so the count is
30 and both comments stand.
- `CLAUDE.md`: main rewrote the `bytesUp`/`bytesDown` bullet (a relayed response
is counted now, with extproc's body-free arm the one exception) and added
`ttfbMs`; this branch added the guard's `dest-private` sentence to
`tunnelReason` and the `dialAddr` bullet. Took main's rewrite verbatim and
re-applied both guard additions on top.
- `docs/session-api.md`: same shape — main's `ttfbMs` bullet plus this branch's
`destination_private` sentences.
Verified: CGO_ENABLED=0 go build ./... clean; sessionapi, pipeline, egressguard,
forwardproxy and cost/usage tests pass.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
…rent refusal (#1484)
Two review findings from the CodeRabbit pass, each confirmed against the code
before fixing and each with a test that fails without its fix.
**A zoned IPv6 literal reached the host's own address.** netip.Addr equality
includes the zone, and net.InterfaceAddrs reports the host's addresses unzoned,
so `[2001:db8::5%eth0]` compared unequal to the `2001:db8::5` the host owns and
walked past hostOwns — writing a zone the host itself would ignore was enough.
CheckAddr now drops the zone for the CHECK and keeps it for the DIAL, since a
link-scoped destination needs it to pick an interface.
hostOwns was the whole exposure: loopback, link-local, private and CGNAT are
range predicates, and a zone does not move an address out of a range (pinned by
TestCheckAddr_ZonedV6StillRefused). Equality is the one place a zone bites.
Stripping it also fixes a false refusal in the other direction — a permitted
zoned ULA was being refused, because Prefix.Contains is false for any zoned
address, so no permit could ever match one.
The NAT64 decode now runs on the zone-stripped address too, which is strictly
better: nat64Prefix.Contains was false for a zoned address, so a zoned NAT64
form previously skipped the embedded-v4 check entirely.
Tests go through CheckAddr, not hostOwns: a test that strips the zone itself
before calling hostOwns asserts the fix rather than the path, and passes against
the unfixed code — I wrote that version first and it did. Verified both new
tests fail before the fix (`= "[2001:db8::5%eth0]:443" with no refusal`) and
pass after. `ifaceAddrs` joins `resolve` as a test seam, because the host-owned
rule is the one refusal that depends on the machine the test runs on — on this
laptop the only host-owned non-private address is IPv4, which cannot carry a
zone, so the bug was untestable without it.
**The transparent listener's refusal reported an error to Finishers.**
handleConnect sets pctx.StatusCode = 403 before its tl.close; this path did
not, and OutcomeFromContext reads a zero StatusCode as OutcomeError. So the
three listener paths disagreed about the same refusal, this one reporting a
failure for what CLAUDE.md, docs/session-api.md and framework-architecture.md
all call a delivered 403 the Finisher sees as an allow. Nothing noticed because
no status reaches the client on this path — it speaks no HTTP to the agent — so
the field exists only for the Finishers and the row.
Verified: full core suite, 73 packages, 0 failures. go vet and gofmt clean on
every touched package. agentop's failures (launchd/systemd/service-manager and
two server-picker TUI tests) reproduce identically on clean main — sandbox
limitations, not this change.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Three conflicts, all the same additive shape — main and this branch each appended to the
same event-schema prose, mostly around #1532's new ttfb field:
File
Resolution
core/sessionapi/summary_test.go
Main added Ttfb, this branch added DialAddr, each as "the 29th kept field". Both are kept, so the count is 30 and both comments stand.
CLAUDE.md
Took main's rewritten bytesUp/bytesDown bullet (a relayed response is counted now, extproc's body-free arm the exception) and its ttfbMs bullet verbatim, then re-applied this branch's dest-private sentence on tunnelReason and the dialAddr bullet.
docs/session-api.md
Same: main's ttfbMs bullet plus this branch's destination_private sentences.
Nothing was dropped from either side, and no behaviour changed in the merge — it is
prose and one test constant.
Both from the CodeRabbit pass, both confirmed against the code before fixing, each with a
test verified to fail without its fix. Detail in the inline replies.
A zoned IPv6 literal reached the host's own address.netip.Addr equality includes
the zone; net.InterfaceAddrs reports addresses unzoned. CheckAddr now strips the
zone for the check and keeps it for the dial. This was also a false refusal in the
other direction — Prefix.Contains is false for zoned addresses, so no permit could
match one, and a permitted zoned ULA was being refused.
The transparent listener's refusal reported an error to Finishers. Both CONNECT
paths set pctx.StatusCode = 403; this one did not, and OutcomeFromContext reads
zero as OutcomeError. The three listener paths disagreed about the same refusal.
@huang195 — your two must-fixes were already addressed in b3dcd1f before this; nothing
in these two commits revisits them. The countsAsError exemption and the hostOwns
address-not-subnet fix are both still in place, with their tests. This needs a fresh look
only at the merge resolution and the two new fixes.
Verification
Full core suite: 73 packages, 0 failures
go vet and gofmt clean on every touched package
Both new egressguard tests and the new transparent test confirmed failing before their
fixes and passing after
cmd/agentop has failures in launchd/systemd/service-manager tests and two
server-picker TUI tests. I checked these against a clean main worktree at 43cf553 and
they fail identically there — sandbox limitations (no launchd/systemd access), not this
change.
CodeQL on #1549 flagged "Log entries created from user input" at the four
slog.Error sites relayUpgradedWebSocket added: r.Host is client-controlled,
and a control rune forged into it would forge a log entry — the same
CWE-150 shape #1539's log lines got (2a3cc17 there).
- Carry this branch the rename that commit made, pipeline.sanitizeUA →
pipeline.SanitizeControlRunes, verbatim (the client.go and context.go
hunks only — its listener hunks belong to #1484's own code). Both open
PRs now hold one byte-identical change, so whichever merges first leaves
the other conflict-free; one shared copy of the rule is the point of the
export, and a third loop beside the ledger's sanitizeLabel is the
outcome it exists to avoid.
- Apply it to r.Host at all four sites. The error values stay raw: a
hijack error is the runtime's own text and the write/flush failures are
syscall errors, neither carrying client-chosen bytes — the same line
#1539 drew between what a client controls and what it merely causes.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
… lines
CodeQL on #1548 flagged "Log entries created from user input" at the
serveOutbound refusal (host, method, path), the redirect re-check
(host, requested host) and the CONNECT refusal (host): all are
client-controlled, and a control rune forged into any of them would
forge a log entry - the same CWE-150 shape #1539's egress guard was
flagged for, fixed there in 2a3cc17.
- Port that commit's pipeline half verbatim - the same hunks, so the
two PRs carry identical changes and whichever merges first wins
cleanly: rename pipeline.sanitizeUA to pipeline.SanitizeControlRunes,
the rule unchanged (C0/DEL/C1/bidi/zero-width and invalid UTF-8
replaced with U+FFFD).
- Apply it at every log site this PR adds. The refusal's wire body and
session details stay raw: the body is the MOCA contract's exact
bytes, and the session API JSON-encodes what it serves.
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
…ops there
CodeQL re-flagged all four relayUpgradedWebSocket log lines at 136d801:
passing r.Host through pipeline.SanitizeControlRunes did not clear "Log
entries created from user input", because go/log-injection recognizes
exactly two sanitizers — strings.ReplaceAll(s, "\n"/"\r", ...) and %q
formatting (LogInjectionCustomizations.qll in github/codeql) — and a
custom function is invisible to it however thorough. The same is true on
#1539: 2a3cc17 sanitized its flagged lines and the finding survived at
that PR's head too.
- Route both of SanitizeControlRunes' returns through
strings.ReplaceAll(x, "\n", "") — a no-op by construction, since every
control rune (newline included) is already replaced by the time either
return runs, and strings.Replace hands back its input unchanged when
the needle is absent (Count==0 fast path, no allocation, so the
request-path budget the fast path's comment promises still holds). The
call exists to be the one shape the query recognizes, so the taint
stops at this function for every present and future caller instead of
each log site being flagged anew.
- Deliberately NOT mirrored into the ledger's and usage's sanitizeLabel
copies, which share the substitution rule: their outputs go to durable
rows and the usage ring, never a log sink, so the query's sink never
sees them. The substitution rule itself is unchanged everywhere.
- The rejected alternative was a CodeQL model pack teaching the query
about this function — the officially blessed mechanism, but pack
infrastructure this repo does not carry, for what two no-op calls do
here.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
CodeQL on #1548 flagged one high-severity reflected-XSS alert at
httpx.WriteRejection's body write: the refusal body reflects the
client-named destination, and a "host" carrying HTML metacharacters
would reach the response bytes raw.
html.EscapeString the name. Every name the MOCA contract defines - a
host, a VM id - is drawn from a character set EscapeString never
touches, so the conformance bytes ("destination_denied: off.test\n")
are identical for every legitimate input; the escape only bites on
input no valid destination can carry. Reason stays raw: it never
reaches the wire body on this path. TestMocaRefusal pins both.
The three medium log-injection alerts on the refusal log lines remain
open, matching #1539's precedent: the values pass through
pipeline.SanitizeControlRunes (previous commit), which neutralises
control runes at runtime but is not a barrier CodeQL can prove - a
new medium alert does not fail the CodeQL check.
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
6cae5d1 did not clear the finding — CodeQL still reported all four
relayUpgradedWebSocket log lines at that commit. The barrier has to sit
in the sink's own function: go/log-injection's recognized ReplaceAll
shape (its test suite proves the shape only in the logging function's
body; a barrier inside a custom callee does not cut the callee's taint
summary, which is what 6cae5d1 tried). This also explains why #1539's
sanitized Debug stayed flagged: beyond host and method it logs
ref.Addr.String(), parsed from the client's own host string — an
unfenced value on that line.
- Revert SanitizeControlRunes to the pre-fence body, byte-identical to
#1539's copy again — the in-function fence demonstrably did nothing.
- Fence in relayUpgradedWebSocket instead: one local, host := the
sanitizer's output passed through strings.ReplaceAll(x, "\n", "") — a
no-op by construction, since every control rune is already replaced —
computed once at the top and used by all four log lines. The call has
to stay in this function's body; a helper would put it back inside a
callee, which is why the comment says not to lift it.
- The error values stay raw, as before: hijack, write and flush errors
are runtime and syscall text, not client-chosen bytes.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
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Both round-2 threads are fixed at 3873b1c. I checked each one by reverting it:
Dropping WithZone("") fails TestCheckAddr_ZonedV6DoesNotEscapeHostOwned and TestCheckAddr_ZoneKeptOnTheDialedAddress.
Dropping the transparent path's pctx.StatusCode = 403 fails TestTransparent_EgressGuardRefusalReportsAnAllowToFinishers with outcome = error/0.
Round 1's fixes survive the merge with main: countsAsError, hostOwns on the address, the NAT64/CGNAT/fd00:ec2::254 rules, and LookupPort. The docs still carry the destination_private, dest-private and dialAddr text. The touched packages pass under -race, and go vet and gofmt are clean.
There is one suggestion (an unpinned fix) and one nit, both inline. Neither blocks.
Author: mrsabath (MEMBER — maintainer) Areas reviewed: Go (egressguard, forwardproxy transparent path, cost/usage), docs after the merge Agent/IDE config (.claude/.vscode): none Commits: 6 commits, all signed-off: yes CI status: passing
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suggestion: The NAT64 half of this fix has no pin. Your reply says a zoned NAT64 form used to skip the embedded-v4 check, and that is right. I confirmed it with a scratch test: before the fix, [64:ff9b::7f00:1%eth0]:80 and [64:ff9b::a9fe:a9fe%eth0]:80 were both allowed, which is loopback and the metadata address. After the fix both are refused.
If you put nat64Embedded(dialAddr) back on this line, every test in egressguard and forwardproxy still passes. Please add those two addresses to the list in TestCheckAddr_ZonedV6StillRefused. The metadata one matters most, because it is never-permitted.
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You're right, and it's worse than "no pin" — thank you for checking by reverting, because
that is what exposed it.
Confirmed your result and measured what the gap costs. With nat64Embedded(dialAddr) put
back:
Address
Reverted
Fixed
[64:ff9b::7f00:1%eth0]:80 (127.0.0.1)
allowed
refused
[64:ff9b::a9fe:a9fe%eth0]:80 (169.254.169.254)
allowed
refused
unzoned controls
refused
refused
So a written zone reached loopback and the metadata service, and as you say the metadata
one is never-permitted space — no permit_cidrs value is supposed to open it. And every
test in egressguard and forwardproxy stayed green throughout, which is exactly the
property that makes it dangerous: nothing would have told the next person.
Both addresses are now rows in TestCheckAddr_ZonedV6StillRefused with the measurement in
the comment, and I made the comment say that the zone-strip and the decode are one fix,
not two — nat64Prefix.Contains is false for a zoned address, so before the strip the
decode never ran on one. That framing is the thing I want the test to protect, since the
two are separable-looking lines.
Fixed in #1556 rather than here, so this PR keeps your approval and merges on it. Same for
the zero-value doc nit.
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nit: "the zero value refuses nothing" is not true. A zero Guard{} still refuses a loopback or private literal: check runs, and with a nil permit list nothing opens it. Only names fail, because resolve is nil. The new fallback at line 250 says the opposite of this line ("a zero-value Guard ... still asks the host").
Suggest: "the zero value checks literal addresses but cannot resolve names." The "one built before this field existed" clause at line 251 can go too. A struct cannot predate its own field at runtime.
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Correct on both counts, and the doc was contradicting the fallback comment I added in the
very same commit — thank you.
Verified a zero Guard{}:
Input
Result
127.0.0.1:443
refused
10.0.0.5:443
refused
169.254.169.254:80
refused
93.184.216.34:443 (public)
allowed
example.com:443 (name)
egressguard: no resolver configured
So check runs normally and an empty permit list opens nothing; only names fail. Reworded
to your suggestion — "checks literal addresses but cannot resolve names" — plus the public
and name behaviours spelled out, since the interesting part is that it is a partial
guard rather than an inert one.
Dropped the "one built before this field existed" clause too. You're right that a struct
cannot predate its own field at runtime; I was describing a migration concern that does
not exist.
Fixed in #1556, keeping this PR's approval intact.
Brings in rossoctl#1537 and rossoctl#1539. Both sides added SessionEvent fields and forward-proxy imports: kept both. main's DialAddr took the field count to 30 and this branch's Proc, ClientProc and SessionHeader add three, so the merged struct has 33.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Hai Huang <huang195@gmail.com>
Resolves the conflict with main, which has since merged #1539 (the forward
proxy dial refusal) and #1537 (the plaintext-credential refusal). Both
conflicts were add/add in core/listener/egressguard and both resolved to this
branch's side, which is the change the PR exists to make:
- guard.go: the corrected zero-value Guard doc. The old "refuses nothing and
dials nothing" text on main is what this branch set out to fix, so main's
side is the stale one.
- guard_test.go: the two zoned NAT64 rows and the comment recording what they
measured. Additive; main's side simply predates them.
The branch was cut before #1537, so merging it without this would have deleted
that feature — the plaintext gate, its three test files, the staticinject
plugin changes and its doc, about 600 lines. Those merged cleanly and are kept;
the diff against main is now only the 24 lines this PR actually adds.
Verified: full core suite with CGO_ENABLED=0, 0 failures, including the
staticinject, extproc and reverseproxy packages #1537 brought in; go vet and
gofmt clean on the touched packages. TestCheckAddr_ZonedV6StillRefused passes
with the two NAT64 rows.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
main gained the egress guard (#1539) and the plaintext-credential
refusal (#1537), which touch the same files as this branch. Resolved by
keeping both sides:
- forwardproxy/server.go: main's guard-checked dialTarget, dialed through
this branch's dialUpstream seam instead of net.DialTimeout, so the
WebSocket tests' dial hook still applies; both new imports.
- pipeline/session.go: TunnelWebSocket and ErrorKindTurnInterrupted
beside TunnelDestPrivate and ErrorKindDestinationPrivate.
- cost/usage: turn_interrupted and destination_private both exempt from
the error count.
- config: this branch's responses_websockets in place of the
decline_responses_websockets field main still had, plus main's
EgressGuard field and its test. EgressGuard's comment no longer
points at the removed field.
- CLAUDE.md, docs/session-api.md: the WebSocket text beside main's
egress-guard text, minus main's line describing the removed boolean.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Alan Cha <Alan.cha1@ibm.com>
Resolve conflicts from #1539 (egress guard + SanitizeControlRunes
rename), #1537, and #1536 landing on main while this branch carried
parallel edits to the same files:
- core/pipeline/client.go: take main's evolved SanitizeControlRunes
doc; drop this branch's now-superseded paragraph (body unchanged).
- core/tlsbridge/upstream.go: keep this branch's WebSocket/requiresHTTP1
doc paragraph ahead of main's new variadic NewUpstreamClient signature
and WithDialContext (egress guard dialer).
- CLAUDE.md, docs/session-api.md: combine both sides' parallel doc
additions — WebSocket forwarding next to the egress guard's 403
destination_private behavior.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Brings in #1539 (egress guard, 403 destination_private) and #1537
(plaintext_credential), both now on main, and resolves the four
conflicts they create with this branch:
- core/listener/forwardproxy/server.go, cmd/cortex/main.go: additive
import conflicts — main adds egressguard, this branch adds
egressallow. Both are kept.
- core/pipeline/client.go: both branches exported
SanitizeControlRunes with its own doc comment. #1539 landed first,
so main's comment stands and this branch's duplicate is dropped —
the function body is identical.
- CLAUDE.md: both document a 403 refusal in the same event-schema
paragraph. Both are kept, plus a note on how they compose: the
allow list judges the NAME before DNS, the guard judges the ADDRESS
it resolved to at the dial, so an allow-list entry is not a permit
for the guard.
One conflict git could not see, because both sides ADDED the file:
#1539's egressguard_test.go and this branch's egressallow_gate_test.go
each define connectRaw, which is a redeclaration in package
forwardproxy. The two bodies are identical, so this branch's copy is
removed and the one on main is used; `bufio` and `net` go with it.
`go vet` caught it — `go build` does not compile test files.
Verified on the merge result: core go test 72 ok, the only failures
being core/plugins and core/plugins/opa, which fail to build on this
machine for lack of a cgo toolchain and do so on unmodified main too.
cmd/cortex ok. gofmt, go vet and go mod tidy -diff clean on both
touched modules.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* feat: deny-by-default egress allow list for the forward proxy
A MOCA sandbox may reach only the destinations its operator lists
(#1483, MI1 8.5 item 3). listener.egress_allow_hosts holds exact
host:port entries; when the list is on, an off-list CONNECT target,
absolute-form URL host, or plugin-redirected dial target is refused
before DNS resolution and before any dial, with the MOCA wire shape:
403, X-Moca-Egress-Error: destination_denied, text/plain body
"destination_denied: <host>\n".
- core/listener/egressallow: the matcher. Entries are exact
host:port (portless or wildcard entries are startup errors - a
guessed port would widen the boundary); hosts compare lowercased,
trailing-dot-stripped, IPv6 canonicalized. A portless destination
is judged at its scheme's default (80 http, 443 otherwise), so
http://host/x means host:80. Nil matcher = feature off, today's
behavior unchanged.
- pipeline.MocaRefusal: shared constructor for the named-refusal
wire shape, so listeners and plugins (#1481's plaintext_credential
gate) render one shape.
- forwardproxy: the gate runs before skip_hosts (the allowlist is
the outer boundary - a skip pattern cannot exempt an off-list
host), records a denied-phase session row with an egress-allowlist
invocation naming the host, and re-checks redirect targets before
the dial so a redirecting plugin cannot steer bytes off-list.
- cmd/cortex: config wins, the MOCA_EGRESS_ALLOW env var is the
fallback channel the conformance harness drives.
Auditing is the denied session row today; the moca JSON audit
channel and vm_id are #1482/#1476-77. extproc and the transparent
listener are follow-ups.
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
* fix: sanitize client-controlled values in the egress allow list's log lines
CodeQL on #1548 flagged "Log entries created from user input" at the
serveOutbound refusal (host, method, path), the redirect re-check
(host, requested host) and the CONNECT refusal (host): all are
client-controlled, and a control rune forged into any of them would
forge a log entry - the same CWE-150 shape #1539's egress guard was
flagged for, fixed there in 2a3cc17.
- Port that commit's pipeline half verbatim - the same hunks, so the
two PRs carry identical changes and whichever merges first wins
cleanly: rename pipeline.sanitizeUA to pipeline.SanitizeControlRunes,
the rule unchanged (C0/DEL/C1/bidi/zero-width and invalid UTF-8
replaced with U+FFFD).
- Apply it at every log site this PR adds. The refusal's wire body and
session details stay raw: the body is the MOCA contract's exact
bytes, and the session API JSON-encodes what it serves.
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
* fix: HTML-escape the name in MocaRefusal's body (#1483)
CodeQL on #1548 flagged one high-severity reflected-XSS alert at
httpx.WriteRejection's body write: the refusal body reflects the
client-named destination, and a "host" carrying HTML metacharacters
would reach the response bytes raw.
html.EscapeString the name. Every name the MOCA contract defines - a
host, a VM id - is drawn from a character set EscapeString never
touches, so the conformance bytes ("destination_denied: off.test\n")
are identical for every legitimate input; the escape only bites on
input no valid destination can carry. Reason stays raw: it never
reaches the wire body on this path. TestMocaRefusal pins both.
The three medium log-injection alerts on the refusal log lines remain
open, matching #1539's precedent: the values pass through
pipeline.SanitizeControlRunes (previous commit), which neutralises
control runes at runtime but is not a barrier CodeQL can prove - a
new medium alert does not fail the CodeQL check.
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
* fix: Deny a stray-bracket destination instead of panicking (#1483)
`splitPort` took its bracketed-IPv6 branch on a `]` found anywhere in the
string, then indexed `s[1:i]` assuming a `[` at `s[0]`. The destination is
client-chosen — a CONNECT authority or an absolute-form URL host — so
`CONNECT ]:443` (or `GET http://]:80/`, which `url.ParseRequestURI`
accepts) made `LastIndex` return 0 and `s[1:0]` panic.
net/http recovered it, so the proxy stayed up and nothing was dialed, but
any client could write a stack trace into the log on every request, and
the refusal row never landed — the audit event a denial is supposed to
leave was exactly what the panic skipped. A parser on a trust boundary
does not get to panic.
The branch is now taken only on a leading `[`; a stray `]` is simply not
host:port and falls through to be denied like any other unparseable
destination, with its audit row. An opened-but-unclosed `[::1` is an
error rather than a different slice bound.
Also: an unbracketed IPv6 entry (`2001:db8::1`, `::1`) passed `New` and
split into host `2001:db8:` / port `1` — an entry no destination can ever
match, because a request carries a v6 literal bracketed. It failed closed,
but the operator believed they had allowed a host and had allowed nothing,
and the contract is that entries which silently empty the boundary are
startup errors. It is one now, naming the `[<address>]:<port>` spelling
that works. Bracketed entries are unaffected: their host keeps its colons
legitimately.
Tests: `TestEgressAllow_RefusesStrayBracketDestination` drives `]:443`,
`]`, `]]:443` and `a]b:443` through the real `Handler()` and pins the 403,
the untouched origin and the denied row — reverting only the source fix
reproduces `http: panic serving … slice bounds out of range [1:0]`;
`TestEgressAllow_StrayBracketGETRefused` covers the absolute-form half;
`TestAllows_StrayBracketDeniedNotPanic` and
`TestNew_RejectsUnbracketedIPv6Entry` pin the matcher directly, including
that `[::1]:443` still parses.
Reported by @huang195 in review of #1548.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* docs: Name the listener scope of the egress allow list (#1483)
The field comment and CLAUDE.md both called the allow list the "outer
boundary" and "deny-by-default" without saying which listener it gates.
It is the forward proxy's, and "outer" means outer with respect to
`skip_hosts` — not with respect to every way a byte leaves the pod.
Two paths it does not cover, both verified rather than assumed:
- the transparent listener: HandleTransparentConn builds its own pctx
and dials the recovered destination (transparent.go:143) without
consulting EgressAllow. All three gates are on forward-proxy HTTP
paths — two in serveOutbound, one in handleConnect.
- extproc: no EgressAllow reference anywhere in the package. Only
cmd/cortex builds a Matcher, and only onto the forward proxy.
That matches the scope the PR claims (MOCA shape A is the proxy-sidecar
forward proxy; #1483 names CONNECT plus absolute-form), so this is a
documentation fix only — no enforcement change and no startup warning,
per the review note. What was missing was telling an operator that a
deployment which also redirects transparently, or runs envoy-sidecar,
has to hold its egress somewhere else too.
Raised by CodeRabbit in review of #1548.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* docs: Name enforce-redirect in the egress allow list's scope note (#1483)
Takes CodeRabbit's committable suggestion on top of 3f47224, which had
already named the two uncovered listeners but described the first one in
the wrong vocabulary: "a deployment that also redirects traffic
transparently" is the implementer's phrasing, not the operator's. The
terms that appear in their own config and in the rest of this file are
enforce-redirect and iptables REDIRECT, so both the field comment and
the CLAUDE.md entry now say that egress which iptables REDIRECTs to
listener.transparent_proxy_addr is not filtered by this list.
Also records the contrast the suggestion sits next to, because the two
notes are adjacent in this struct and read as contradictory otherwise:
the transparent listener does not consult SkipHosts either, and
transparent.go says so at length with a "don't add it" warning. There
the omission HARDENS the boundary — a skip pattern must not be able to
self-exempt from the hard egress guard — while here the same omission
leaves a way around the allow list. Same listener, same absent check,
opposite consequence.
Verified rather than assumed, as with the parent commit: the transparent
listener has no SkipHosts reference on its own path (only the comments
explaining why), and no EgressAllow reference at all.
Documentation only — no enforcement change, per the review note.
gofmt, go vet and core/config tests clean.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
---------
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
#1556)
* fix: refuse private destinations at the forward proxy dial (#1484)
Arms an opt-in SSRF dial guard on every outbound dial the forward proxy
makes: CONNECT tunnels, plain and bridged requests, transparent redirects,
and skip_hosts traffic too — a bypass must not become an SSRF bypass. Each
destination is resolved once, refused with 403 destination_private when the
address is loopback, link-local (including 169.254.169.254), RFC 1918 /
unique-local space, or one of this host's own interface addresses and no
permit covers it, and then dialed at the checked address, so DNS rebinding
cannot re-answer between the check and the connect. Link-local, unspecified
and multicast addresses are never permitted, whatever permit_cidrs says.
Off by default: a sidecar's ordinary upstreams — Keycloak, in-cluster
services, a laptop's local model — live in exactly the refused space, so
defaulting this on would break every existing deployment.
- core/listener/egressguard: the guard itself (CheckAddr / DialContext /
DialTimeout, typed Refusal), resolver injectable so the tests pin the
resolve-once property against a counting stub
- forwardproxy: WithEgressGuard option (NewServer signature unchanged);
under mTLS the guard sits inside the dialer so a refused address never
gets a TLS ClientHello; handleConnect and the transparent listener check
before the dial and reuse the checked address for the bridge fall-open
re-dial; serveOutbound renders a Refusal as the listener's standard 403
rejection with error.kind destination_private
- pipeline: SessionEvent.DialAddr on the wire (dialAddr, omitempty) — the
audit trail pairing the name the client asked for with the address
dialed; new tunnelReason "dest-private" (within agentop's 18-char PLUGIN
column cap)
- tlsbridge: WithDialContext so the bridge's re-origination client dials
through the guard — the bridge must not become the path around it
- config: listener.egress_guard {enabled, permit_cidrs}; a listener.*
field, so it inherits the restart-on-reload rule
The moca conformance shapes are pinned by tests: private_address_403
(CONNECT and GET to loopback, upstream never dialed),
metadata_address_403_even_if_permitted (169.254.169.254 under 0.0.0.0/0),
and the rebinding case's Cortex half — resolve exactly once, dial the
first checked answer, open row carries dialAddr.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: tighten two review findings on the egress guard (#1484)
Self-review of #1539, both accuracy rather than behavior:
- SessionEvent.DialAddr's comment claimed the field is absent "on events
that dialed nothing", but a guarded plain or bridged request dials
through the guarded transport and records no dialAddr either — only a
tunnel's open row carries it. Say that instead: present only on a
tunnel's open row, absent when the guard is off. session-api.md already
said exactly this.
- The "egress guard on" boot log fired wherever the guard was configured,
including a reverse-only deployment where no forward proxy exists to
enforce it. The guard is still built before the TLS bridge (the bridge's
re-origination client consumes it), but the announcement now logs in the
forward-role block, where it is true.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: sanitize client-controlled values in the egress guard's log lines (#1484)
CodeQL on #1539 flagged "Log entries created from user input" at the
serveOutbound refusal Debug: r.Host and r.Method are client-controlled,
and a control rune forged into either would forge a log entry — the same
CWE-150 shape the User-Agent path already guards against.
- Rename pipeline.sanitizeUA to pipeline.SanitizeControlRunes. The rule
(C0/DEL/C1/bidi/zero-width and invalid UTF-8 replaced with U+FFFD) and
its rationale are unchanged; only the name now says what it is: the
rule applies to any client-controlled string headed for a surface a
terminal or a file renders, not only a User-Agent. Exported so the
listeners can use the one copy rather than grow a third loop beside
the ledger's sanitizeLabel.
- Apply it at every log site this PR added: the serveOutbound refusal
Debug (Host, Method), handleConnect's refusal Warn (Host) and
resolution-failure Warn (Host and the error string, which embeds the
name via net.DNSError), and the transparent listener's refusal Warn
(host — sniffed off the client's own bytes as SNI or a Host header).
Values that are not client-controlled — the guard's parsed address,
the kernel's SO_ORIGINAL_DST literal — stay raw.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: address review findings on the egress guard (#1484)
Hai's review of #1539, all six findings:
- countsAsError only exempted upgrade_declined, so /v1/usage counted the
guard's 403 destination_private as an error while four places of
documentation said it does not. The kind is now exempted alongside
upgrade_declined — a refusal is the policy working, not the proxy
failing — with a test next to the declined-upgrade one that pins the
distinction from an origin's own 403.
- The "host's own addresses" check tested the interface's on-link PREFIX,
refusing every LAN neighbour and, on a cloud VM with a public address
on a large on-link prefix, ordinary public upstreams. hostOwns now
compares the interface's address itself; a test pins the distinction
with the exact prefixes from the review.
- fd00:ec2::254 (AWS metadata, IPv6 form) is ULA and so sat in the
permit-able set; it is never-permitted now. 100.64.0.0/10 (RFC 6598
CGNAT, home of Alibaba's metadata service) is refused like private
space and permit-able like it. A well-known-prefix NAT64 address
(64:ff9b::/96) is checked by the IPv4 it embeds, so the wrapped
127.0.0.1 is refused while the v6 form stays the dial target. All
three are named in the package comment and the docs.
- DialTimeout had no caller; deleted.
- The port is parsed with net.LookupPort before the resolve: a
service-name port ("example.com:https") dials again instead of 502ing,
and a bad port costs no DNS lookup.
- The SanitizeControlRunes doc block opened with "sanitizeUA replaces…",
a function that no longer exists; the rename paragraph now leads the
block and the seven other comment references follow the new name.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: strip the IPv6 zone before the refusal check; 403 on the transparent refusal (#1484)
Two review findings from the CodeRabbit pass, each confirmed against the code
before fixing and each with a test that fails without its fix.
**A zoned IPv6 literal reached the host's own address.** netip.Addr equality
includes the zone, and net.InterfaceAddrs reports the host's addresses unzoned,
so `[2001:db8::5%eth0]` compared unequal to the `2001:db8::5` the host owns and
walked past hostOwns — writing a zone the host itself would ignore was enough.
CheckAddr now drops the zone for the CHECK and keeps it for the DIAL, since a
link-scoped destination needs it to pick an interface.
hostOwns was the whole exposure: loopback, link-local, private and CGNAT are
range predicates, and a zone does not move an address out of a range (pinned by
TestCheckAddr_ZonedV6StillRefused). Equality is the one place a zone bites.
Stripping it also fixes a false refusal in the other direction — a permitted
zoned ULA was being refused, because Prefix.Contains is false for any zoned
address, so no permit could ever match one.
The NAT64 decode now runs on the zone-stripped address too, which is strictly
better: nat64Prefix.Contains was false for a zoned address, so a zoned NAT64
form previously skipped the embedded-v4 check entirely.
Tests go through CheckAddr, not hostOwns: a test that strips the zone itself
before calling hostOwns asserts the fix rather than the path, and passes against
the unfixed code — I wrote that version first and it did. Verified both new
tests fail before the fix (`= "[2001:db8::5%eth0]:443" with no refusal`) and
pass after. `ifaceAddrs` joins `resolve` as a test seam, because the host-owned
rule is the one refusal that depends on the machine the test runs on — on this
laptop the only host-owned non-private address is IPv4, which cannot carry a
zone, so the bug was untestable without it.
**The transparent listener's refusal reported an error to Finishers.**
handleConnect sets pctx.StatusCode = 403 before its tl.close; this path did
not, and OutcomeFromContext reads a zero StatusCode as OutcomeError. So the
three listener paths disagreed about the same refusal, this one reporting a
failure for what CLAUDE.md, docs/session-api.md and framework-architecture.md
all call a delivered 403 the Finisher sees as an allow. Nothing noticed because
no status reaches the client on this path — it speaks no HTTP to the agent — so
the field exists only for the Finishers and the row.
Verified: full core suite, 73 packages, 0 failures. go vet and gofmt clean on
every touched package. agentop's failures (launchd/systemd/service-manager and
two server-picker TUI tests) reproduce identically on clean main — sandbox
limitations, not this change.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* test: pin the zoned NAT64 refusal; correct the zero-value Guard doc (#1484)
Both round-2 review comments. Neither blocks, but the first is a real coverage
gap in my own previous commit.
**The NAT64 half of the zone fix was unpinned.** 3873b1c moved the
embedded-v4 decode onto the zone-stripped address, and I said so in the PR
thread, but nothing tested it: reverting `nat64Embedded(checkAddr)` to
`nat64Embedded(dialAddr)` left every test in egressguard and forwardproxy
green. Confirmed, and confirmed what it costs — with the decode's input
reverted, `[64:ff9b::7f00:1%eth0]:80` and `[64:ff9b::a9fe:a9fe%eth0]:80` are
both ALLOWED, which is loopback and the cloud metadata service, while their
unzoned forms are refused. The metadata one is never-permitted space, so a
written zone was enough to reach it.
Both addresses are now rows in `TestCheckAddr_ZonedV6StillRefused`, with the
measurement in the comment. The two halves are one fix rather than two —
`nat64Prefix.Contains` is false for a zoned address, so before the zone was
stripped the decode never ran on one — and the test now says that, so a later
edit cannot quietly separate them.
**The zero-value Guard doc said the opposite of the truth**, and contradicted
the fallback comment I added in the same commit. A zero `Guard{}` does refuse
a loopback, private or metadata LITERAL: `check` runs and an empty permit list
opens nothing. Only names fail, on the nil resolver. Verified all four cases.
The doc now says "checks literal addresses but cannot resolve names" and names
the public-literal and name behaviours; the fallback comment drops its "built
before this field existed" clause, which was describing something that cannot
happen at runtime.
Verified: full core suite, 73 packages, 0 failures; go vet and gofmt clean. The
two new rows fail against the pre-fix decode input and pass after.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
---------
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* feat: forward WebSocket upgrades on intercepted connections
Issue #1488. The forward proxy stripped Upgrade from every request, so a
WebSocket crossing it — plain or TLS-bridged — reached the origin as a bare
GET and died there. Now the upgrade is forwarded and the 101 spliced.
serveOutbound computes forwardUpgrade (a WebSocket header pair, minus the
Responses-API WebSocket declineResponsesWebSocket still answers 426) and:
keeps Connection/Upgrade through stripForUpstream, normalized to the one
protocol forwarded ("Connection: Upgrade" / "Upgrade: websocket", as
httputil.ReverseProxy normalizes); skips resendIfAsked (a 101 is not a
refused answer); and on a 101 hijacks the client connection and splices
both directions (relayUpgradedWebSocket, modelled on ReverseProxy's
handleUpgradeResponse), with CloseWrite propagating half-closes and the
request context closing the origin's end.
No upgrade-specific client anywhere: net/http pins a request carrying that
exact header pair to HTTP/1.1 (Request.requiresHTTP1), so the bridge's
h2-negotiating upstream client carries the exchange as HTTP/1.1 by itself
— pinned by the bridged test against an h2-capable origin.
The audit is one logical event: the request row, plus a paired 101
response row recorded after both splice directions end, carrying both
directions' byte counts (the one response row besides a tunnel close that
carries both), durationMs over the whole session and ttfbMs the handshake.
Frames after the 101 are relayed byte for byte, never inspected or
buffered; no response plugin runs on a 101. The CONNECT-host check already
covers the bridged upgrade GET (421 test included). RFC 8441 (WebSocket
over h2 downstream) is out of scope and documented as such.
The decline's docs are reworded — it is now a steer (a forwarded Responses
WebSocket works, but its frames are opaque to every parser, so the 426
keeps Codex on observable HTTPS) rather than a capability gap — with
behavior unchanged: on by default, OpenAI hosts only.
Closes#1488
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: sanitize the host in the WebSocket relay's log lines
CodeQL on #1549 flagged "Log entries created from user input" at the four
slog.Error sites relayUpgradedWebSocket added: r.Host is client-controlled,
and a control rune forged into it would forge a log entry — the same
CWE-150 shape #1539's log lines got (2a3cc17 there).
- Carry this branch the rename that commit made, pipeline.sanitizeUA →
pipeline.SanitizeControlRunes, verbatim (the client.go and context.go
hunks only — its listener hunks belong to #1484's own code). Both open
PRs now hold one byte-identical change, so whichever merges first leaves
the other conflict-free; one shared copy of the rule is the point of the
export, and a third loop beside the ledger's sanitizeLabel is the
outcome it exists to avoid.
- Apply it to r.Host at all four sites. The error values stay raw: a
hijack error is the runtime's own text and the write/flush failures are
syscall errors, neither carrying client-chosen bytes — the same line
#1539 drew between what a client controls and what it merely causes.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: fence SanitizeControlRunes so CodeQL's log-injection tracking stops there
CodeQL re-flagged all four relayUpgradedWebSocket log lines at 136d801:
passing r.Host through pipeline.SanitizeControlRunes did not clear "Log
entries created from user input", because go/log-injection recognizes
exactly two sanitizers — strings.ReplaceAll(s, "\n"/"\r", ...) and %q
formatting (LogInjectionCustomizations.qll in github/codeql) — and a
custom function is invisible to it however thorough. The same is true on
#1539: 2a3cc17 sanitized its flagged lines and the finding survived at
that PR's head too.
- Route both of SanitizeControlRunes' returns through
strings.ReplaceAll(x, "\n", "") — a no-op by construction, since every
control rune (newline included) is already replaced by the time either
return runs, and strings.Replace hands back its input unchanged when
the needle is absent (Count==0 fast path, no allocation, so the
request-path budget the fast path's comment promises still holds). The
call exists to be the one shape the query recognizes, so the taint
stops at this function for every present and future caller instead of
each log site being flagged anew.
- Deliberately NOT mirrored into the ledger's and usage's sanitizeLabel
copies, which share the substitution rule: their outputs go to durable
rows and the usage ring, never a log sink, so the query's sink never
sees them. The substitution rule itself is unchanged everywhere.
- The rejected alternative was a CodeQL model pack teaching the query
about this function — the officially blessed mechanism, but pack
infrastructure this repo does not carry, for what two no-op calls do
here.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: fence the relay's log host at the sink, not inside the sanitizer
6cae5d1 did not clear the finding — CodeQL still reported all four
relayUpgradedWebSocket log lines at that commit. The barrier has to sit
in the sink's own function: go/log-injection's recognized ReplaceAll
shape (its test suite proves the shape only in the logging function's
body; a barrier inside a custom callee does not cut the callee's taint
summary, which is what 6cae5d1 tried). This also explains why #1539's
sanitized Debug stayed flagged: beyond host and method it logs
ref.Addr.String(), parsed from the client's own host string — an
unfenced value on that line.
- Revert SanitizeControlRunes to the pre-fence body, byte-identical to
#1539's copy again — the in-function fence demonstrably did nothing.
- Fence in relayUpgradedWebSocket instead: one local, host := the
sanitizer's output passed through strings.ReplaceAll(x, "\n", "") — a
no-op by construction, since every control rune is already replaced —
computed once at the top and used by all four log lines. The call has
to stay in this function's body; a helper would put it back inside a
callee, which is why the comment says not to lift it.
- The error values stay raw, as before: hijack, write and flush errors
are runtime and syscall text, not client-chosen bytes.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* test: wait for the reverse proxy's deferred response row everywhere
Go CI (core) failed on this PR twice and on main once — at 49f909c,
the merge of #1532 — always the same shape: a reverseproxy test reads
the session store right after the client finished and finds the request
row but not the response row. #1532 defers that row to the end of
ReverseProxy's body copy (recordOnEOFBody) so its Duration and byte
counts are complete, which opened the race: a client that drains a
small body can be back and inspecting the store before the server's
copy finished. #1532 deflaked its own test and recording_test.go with
waitForResponseEvent but left the other same-shaped assertions racing.
- waitForResponseEvent takes the session id now: a rekeyed turn's rows
land under the contextId bucket, not default, which is exactly the
case TestReverseProxy_ModifyResponse_RekeyAndResponseEvent (three of
the failures) asserts on.
- Apply it at every round-trip assertion that was still racing the row:
the rekey test (server_test.go), TestReverseProxyRecordsMethodAndPath
(httppath_test.go — main's failure), the bytescount round-trip helper,
the finalize-context response-row check, and the unreachable-backend
test, whose failure row is appended from errorHandler after the 502
went out. Direct-recorder tests are untouched — their rows are
synchronous by construction.
- The parity suite's reverseproxy driver polls observe() to the same
deadline instead of reading once; its priced-response-headers-only
fixture is the unbuffered arm and failed the same way at 6cae5d1.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: Close the origin and unstrand the splice when a WebSocket relay fails (#1488)
Two CodeRabbit findings on the 101 relay, both confirmed by reproduction before
fixing, each now pinned by a test that fails without its fix.
**A failed splice leaked the origin's connection.** relayUpgradedWebSocket owns
resp.Body once the origin answered 101 — serveOutbound deliberately skips its
Close defer, since closing the body would close the WebSocket — and the
goroutine that closes the origin on context-done is armed only after the hijack
succeeds. Both early returns before it therefore left the origin holding a
connection it believed was an established WebSocket, while the client already
had a 502, until the origin's own idle timeout reaped it. Reproduced through the
hijack-failure path: the origin's copy never returned, so our end was never
closed. Both paths now close their end first.
**A broken splice direction stranded the other, and lost the audit row.** The
splice waits for both directions to report their byte counts. A clean EOF
propagates as CloseWrite and releases its peer; an error carries no such signal,
so the peer stayed blocked in Read with nothing coming. The cost is not just a
goroutine: the 101 row is recorded after both directions end, so a stranded
direction means the upgrade is never evented — the PR's own one-event-per-upgrade
promise lost on exactly the connections worth auditing. Measured with an origin
that RSTs mid-session against a quiet client: the row never arrived past any
deadline; after the fix it lands in ~0.1s.
ReverseProxy sidesteps this by returning after the first result and letting its
deferred closes unblock the other. This function needs both counts, so it closes
explicitly instead. The counts stay correct — io.Copy returns what it copied
before the error, and the closes only release a direction already finished or
broken. Ordering is safe either way: a first result of nil means that direction
already did CloseWrite, which releases its peer, so the second always arrives.
Both tests are listener-level and observe the ORIGIN's view rather than ours —
its handler blocks in a copy that returns only when our end closes, which is the
only honest evidence we released it.
Not taken: the De Morgan's rewrite of `forwardUpgrade` (staticcheck QF1001,
flagged Trivial/unverified). staticcheck runs in neither CI nor pre-commit, so
it gates nothing, and the current form reads as the rule the comment above it
states — "a websocket upgrade, unless it is a declined Responses WebSocket".
The disjunction is equivalent but reads less like that rule.
Verified: full core suite 74 packages 0 failures; go vet and gofmt clean; the
WebSocket and bridge tests 3x under -race with no races.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: Require both upgrade headers, and check the 101's protocol (#1488)
Two gaps in the forwarded-upgrade predicate, both found by driving the real
handler and both fixed here. They share a root cause worth stating plainly:
because stripForUpstream WRITES the normalized Connection/Upgrade pair for
anything treated as an upgrade, a predicate that is too loose does not merely
miss a forward — it manufactures one.
1. A request was treated as a WebSocket upgrade on its Upgrade header alone.
RFC 9110 §7.8 says a sender MUST send Connection: upgrade alongside it and
a recipient ignores Upgrade when Connection does not list it; that is also
exactly the test net/http makes in ReverseProxy's upgradeType, and in
Request.requiresHTTP1 — the very function this PR relies on to pin the
exchange to HTTP/1.1, which also demands both headers.
So a request carrying a bare "Upgrade: websocket" and no Connection token
reached the origin as a well-formed handshake the client never sent, and
when the origin answered 101 its connection was hijacked and spliced.
Measured end to end before the fix: the client, which was waiting for an
ordinary HTTP response, read the origin's post-101 bytes off an opaque pipe
whose frames no plugin inspects. It now takes the ordinary path and the
pair is stripped, so the same request gets a 200.
2. A 101 was spliced without checking what the origin switched TO. A 101 only
says "switching"; its own Upgrade header says to what, which is why
ReverseProxy's handleUpgradeResponse refuses when resUpType != reqUpType.
relayUpgradedWebSocket is modelled on that function but left the
comparison out, so an origin answering "101 Upgrade: h2c" to a WebSocket
handshake was spliced anyway — handing the client a pipe speaking a
protocol it never negotiated, which only the client could then detect,
after the proxy had already committed its connection. Refused with 502
before the hijack now, while a status is still writable, and the refusal
records its response row like every other splice failure.
The response check reuses upgradesToWebSocket, so a 101 must carry the
Connection token too — which RFC 9110 requires of one.
Tests, both verified to fail with only the source fix reverted:
- TestForwardProxy_UpgradeWithoutConnectionTokenIsStripped — bare Upgrade
through the real handler against an origin that WOULD upgrade if asked, so
the only thing keeping the request ordinary is the proxy declining to
forge the pair. Asserts 200, the body, and that the origin saw neither
header.
- TestForwardProxy_RefusesA101ToAnotherProtocol — 101/h2c answer is 502, and
the 502 response row lands.
- TestUpgradesToWebSocket_RequiresTheConnectionToken — the Connection token
table (absent, keep-alive, close, in a list, repeated, "upgrades").
- TestUpgradesToWebSocket_ReadsTheTokenList keeps testing Upgrade token-list
parsing, with its inputs given the Connection token a real request carries.
Docs: the two conditions in docs/framework-architecture.md and CLAUDE.md,
each saying why the check is not a formality.
core go test 73 ok (core/plugins and core/plugins/opa fail to build for lack
of a cgo toolchain on this machine, as they do on unmodified main);
forwardproxy clean under -race -count=2; cmd/cortex ok; gofmt, go vet and
go mod tidy -diff clean.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: Keep a WebSocket's 101 row out of /v1/usage, and mark a broken relay (#1488)
Addresses Hai's review of #1549 — all three comments.
must-fix: the 101 row poisoned the latency aggregate. The row is recorded
after both splice directions end, so outboundResponseEvent's
DurationSince(StartedAt) is the WebSocket SESSION's lifetime, and it is not a
tunnel row, so usage.Record folded it as a request latency. Reproduced at
Hai's own figures: a hundred 500ms requests against one host plus ONE
ten-minute WebSocket reported a 6435.6ms mean (he predicted ~6s), and the
session also counted as Requests +1 — inconsistently, since the upgrade GET's
own request row is not counted.
Fixed by the remedy he preferred: the 101 row now gets the tunnel row's
treatment in the fold, which settles the Requests question with the latency
one. The three reasons the tunnel exclusion gives all apply unchanged —
lifetime not latency, opaque bytes with no model/token/cost, and a quiet
change to what Requests means. Keyed on StatusCode rather than a new event
field because 101 IS the condition: the proxy records this row for no other
status, and after the protocol check added earlier in this review a 101 that
reached a client always means a spliced WebSocket. durationMs stays on the
session timeline, where the lifetime is the feature; only the aggregation
misread it.
Also pinned on the REPLAY path, which only works because ReplayCopy is a
whole-struct copy and so carries StatusCode. A field-by-field copy that
forgot it would put archived WebSocket lifetimes back into the mean on every
restart, silently — TestReplayCopy_KeepsWhatExcludesA101Row holds both that
field and Tunnel.
suggestion: documented the half of the no-resend rule that was not written
down. The condition is keyed on forwardUpgrade — the REQUEST — so it also
covers an upgrade the origin declined with a non-101, which the comment never
said. Hai is right that narrowing it to `resp.StatusCode != 101` would be
wrong, and the reason is now in the comment: the resend path calls
stripForUpstream(again, ownEncoding, false), so a resent upgrade reaches the
origin as a bare GET — a re-auth that cannot carry the upgrade cannot rescue
it. Left request-keyed on purpose, now with a note saying so.
nit: a splice that ends in an error now marks the 101 row with
error.kind "proxy_error", so a WebSocket that died mid-session is
distinguishable from one that closed cleanly instead of showing only
truncated byte counts.
One correction found while implementing that nit, by the assertion added for
it: net.ErrClosed must NOT be marked. A WebSocket normally ends with one side
closing, and the deferred closes then race the direction still blocked in
Read, so an ordinary close reports "use of closed network connection" — the
first version of this flagged every healthy session as broken, and
assertUpgradedRows' new "no error on a clean session" check caught it. Both
halves are now asserted, because a marker that is always set distinguishes
nothing.
Tests, the first verified to fail with only the source fix reverted:
- TestRecord_WebSocket101IsNotARequestLatency — the 100-requests-plus-one-WS
fixture, asserting neither Requests nor the sample-weighted latency mean
moves. Fails without the fix with exactly the figures above.
- TestReplayCopy_KeepsWhatExcludesA101Row — the replay path.
- TestForwardProxy_WebSocketBrokenDirectionDoesNotStrandTheOther now also
requires the error marker; assertUpgradedRows requires its absence on the
clean path.
Docs: CLAUDE.md and docs/session-api.md both state the usage exclusion with
its reason and the error marker's two cases.
core go test 73 ok (core/plugins and core/plugins/opa fail to build for lack
of a cgo toolchain here, as on unmodified main); forwardproxy clean under
-race -count=2; cost/..., sessionapi, cmd/cortex and cmd/agentop ok; gofmt,
go vet and go mod tidy -diff clean.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* fix: forward the origin's half-close over the TLS bridge (#1488)
Both findings from @clawgenti's review. The first is a real hang on the
bridged path, which is the one #1488 is about.
**The origin's half-close never reached the client over the bridge.**
tlsbridge.ServeConn serves the terminated conn through newOneConnListener,
which hands Hijack a *notifyConn — and notifyConn embeds the net.Conn
INTERFACE, so only net.Conn's method set is promoted and CloseWrite is absent
whatever the concrete type underneath is. The splice's
if wc, ok := conn.(interface{ CloseWrite() error }); ok
therefore failed on the bridge, the goroutine sent nil, and nothing was
forwarded. An origin that closed first (RFC 6455 §7.1.1's server-initiated
close, an origin restart, an LB idle timeout) left the agent waiting on a
WebSocket whose other end was gone, while the client→origin copy stayed
blocked on the silent agent — so the 101 row, recorded after BOTH directions,
never landed either. The same one-event-per-upgrade loss as the RST case from
the previous round, on the clean-close path.
Reproduced before fixing, exactly as the review reported:
plain: client read after origin FIN -> EOF after 0.11s
bridged: client read after origin FIN -> i/o timeout after 10s
bridged: no 101 row while the client still held the conn
Fixed by giving notifyConn a CloseWrite that forwards to the wrapped conn. Took
the review's first option rather than the second deliberately: returning an
error when the wrapped conn cannot half-close would reach the splice's
spliceErr, which marks the row error.kind "proxy_error" — so every clean close
on such a conn would read as a broken session, the exact distinction the
previous round's marker exists to preserve. A *tls.Conn, which is what
ServeConn is always handed, does implement CloseWrite, so in practice it
forwards.
New TestWebSocketSplice_OriginClosesFirst covers both paths in one test,
because the bug WAS the asymmetry and splitting them invites fixing one side.
It fails against the unfixed code with the timeout above; verified by removing
the method again afterwards. The review's diagnosis of why this got through is
right: every existing upgrade test has the CLIENT close first, which never
needs the origin's FIN to travel back.
**The 101 exclusion from /v1/usage was not scoped to the forward proxy.** The
reverse proxy records a 101 row too (ModifyResponse's
StatusSwitchingProtocols arm, Direction: Inbound) and records it AT HANDSHAKE
TIME — ReverseProxy hands off the connection instead of copying a body, so a
deferred record would never fire — which makes that row's Duration the
handshake latency, not the session lifetime the exclusion exists to keep out of
the mean. Keyed on status alone, those rows silently vanished from /v1/usage on
every inbound listener: a change in what Requests means, which is the thing the
comment warns against, in the other direction.
Scoped to outbound, as the review's first option. Pinned both ways:
TestRecord_WebSocket101IsNotARequestLatency (outbound excluded) and the new
TestRecord_InboundWebSocket101IsStillARequest, which fails before the change
with requests = 0, want 1. The comment and the matching sentences in
docs/session-api.md and CLAUDE.md now say outbound-only and why.
Verified: full core suite 0 failures; go test -race on forwardproxy, tlsbridge
and cost/usage clean; go vet ./... and gofmt clean. CGO_ENABLED=0 throughout
(core/plugins and core/plugins/opa need runtime/cgo, unavailable in this
sandbox; both pass with it off).
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
* test: name Direction among the fields the 101 exclusion reads (#1488)
Comment only. TestReplayCopy_KeepsWhatExcludesA101Row named StatusCode and
Tunnel as the fields ReplayCopy has to carry for the /v1/usage exclusion to keep
applying on replay, but scoping that exclusion to outbound made Direction a
third, and the comment was not updated with it.
The protection itself was already real, which is why this is a comment and not a
fix: mutating ReplayCopy to mangle Direction to Inbound fails the test's
end-to-end half, with the latency mean moving 500ms -> 300s. The comment now
says that is what the end-to-end half is for, so it does not read as redundant
with the two direct field assertions above it and get dropped.
Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
---------
Signed-off-by: Mariusz Sabath <mrsabath@gmail.com>
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moved this from New/ToDo
to Done
in Rossoctl Issue Prioritization
Implements #1484 — the SSRF guard for the forward proxy's outbound dials.
What it does
When
listener.egress_guard.enabled: true, every destination the forwardproxy dials is resolved once, checked, and dialed at the checked address:
403 destination_privatewhen the address is loopback,link-local (including the cloud metadata address
169.254.169.254),RFC 1918 / unique-local space, or one of this host's own interface
addresses, and no
permit_cidrsprefix covers it.permit_cidrssays —0.0.0.0reaches loopback on every mainstreamstack, and the metadata range is what this guard exists among other
things to protect. The moca conformance case pins this: a permit of
0.0.0.0/0does not open169.254.169.254.tricked, and none is needed to be safe.
permit_cidrscovers prefixes within the refused space (loopback andRFC 1918 / unique-local are permit-able):
127.0.0.1/32for a laptopproxy with a local model,
10.0.0.0/8for an in-cluster deployment.Off by default. A sidecar's ordinary upstreams — Keycloak, in-cluster
services, a laptop's local model — live in exactly the refused space, so
defaulting this on would break every existing deployment. The MOCA-shaped
config enables it.
The issue's design question: where in the dial path
One guard, under every dial site, so no path becomes the bypass:
DialContext(wired viaNewServer's newWithEgressGuardoption — the constructor signature is unchanged)tlsbridge.WithDialContext— a refused destination never gets a re-originated requesthandleConnect, before the dial; the bridge fall-open re-dial reuses the checked address rather than re-resolvingHandleTransparentConn, over the SO_ORIGINAL_DST literal; a refusal is recorded (synthetic 403 close row) but never sent — that path speaks no HTTP to the clientskip_hoststrafficDNS rebinding: resolve once, dial the checked address
The window the guard closes is between the check and the dial — check
one address, dial another. The fix is to commit to one answer and dial it
verbatim:
CheckAddrreturns the address it checked (the literal, or thefirst resolved answer), and every dial site dials that string, never the
original host. A second resolution has no window to change either. The
moca
dns_rebinding_resolved_onceshape — a name answering127.0.0.1then
10.0.0.9, with only127.0.0.1/32permitted — tunnels to127.0.0.1with exactly one lookup; the unit tests pin the lookup countagainst a counting stub resolver.
Observability
tunnelReason: "dest-private"and a 403 close carryingerror.kind: "destination_private"— never confused withdial-failed, which attempted.kind. Like the 426
upgrade_declined, the Finisher sees an allow withthe status (the guard did what it was configured to), and
/v1/usagedoes not count it as an error.
dialAddrfield — thechecked address that was dialed, the audit trail pairing the name the
client asked for with the address the proxy reached. On the wire as
dialAddr(omitempty, so a proxy with the guard off emits nothingnew);
SessionEvent.DialAddrrides the usual round-trip/wire-skew testdiscipline.
destination_privateis the MOCA egress contract's identifier, usedverbatim (as
plaintext_credentialwas in #1481) so the shared conformancesuite matches without a translation table.
Config
A
listener.*field, so it inherits the restart-on-reload ruleautomatically (
validateReloadablecompares the whole block).Tests
core/listener/egressguard: the refusal set table (loopback, metadata,fe80::, fc00::, 0.0.0.0, multicast, v4-mapped), never-permitted under
blanket permits, permits opening covered space, resolve-exactly-once
with a counting stub, first-answer-rules,
errors.Asthrough a*url.Errorwrapper,DialContextlanding on the first checked answer.core/listener/forwardproxy: the three moca shapes end to end —CONNECT and GET to loopback → 403, upstream never dialed, both rows
recorded; metadata refused under
0.0.0.0/0; permitted loopbacktunnels with
dialAddron the open row; and the off-by-defaultcompatibility contract (no guard → tunnels exactly as before).
core/config: off without the block, on with it, explicitfalse.core/sessionapi: the summarize-shape guard count, with thetimeline-vs-detail decision recorded (kept — a scalar, the struct copy
carries it).
Docs:
framework-architecture.md(newlistener.egress_guardsection),session-api.md(dialAddr, the error kind, the tunnel reason),CLAUDE.mdevent-schema bullets.Closes #1484
Assisted-By: Claude (Anthropic AI) noreply@anthropic.com
Summary by CodeRabbit