Partial

RFC 1994 - PPP Challenge Handshake Authentication Protocol (CHAP)

Every requirement this repository extracted from RFC 1994, the tests bound to it, and what a reader has verified about them. This summary is enrolled and gated by ./le rfc check.

Overview

Positive

what Ze has

Tested both ways29.4%5 of 17 binding obligations

a positive test proves Ze does what the requirement demands and a negative one proves it refuses what the requirement forbids

One polarity plus reason52.9%9 of 17 binding obligations

the requirement admits no counter-case, so one polarity plus a recorded reason is the whole proof available for it

One polarity, unexcused0.0%0 of 17 binding obligations

one direction is tested, the other is neither tested nor excused, and nothing states which

Proven by a recorded break0.0%0 of 24 tagged units

a red was observed once under a recorded procedure, and the unit, the claim and the producer it rested on still hash to what was recorded. The break is not re-run. A test pair is not a proof until one has been observed

Neutral

measures that are neither good news nor bad

Gated MUSTs17of 27 this summary declares

MUST-level requirements the gate HOLDS. A population, not a result: the shares beside it are what says how Ze stands

Out of scope0of 17 gated MUSTs

a {not-applicable} annotation says the obligation does not bind Ze. Scope, not coverage: it is in no share below

Negative

what Ze owes

No test at all17.6%3 of 17 binding obligations

no test carries the requirement id, whether or not a gap states why

The 4 shares marked as a part above are the whole of the 17 obligations that bind Ze: they add to 100%. Proven by a recorded break is a share of TAGGED UNITS, a different population, so it is not one of them.

How to read the colors

A color names what the measure MEANS, not how well Ze scores on it. Green is a good outcome at any value, red is a bad one, and neither a population nor a scope count is an outcome, so both take no color. The number under the label is what says how far Ze has got.

Card	Tone here	Why that color
Gated MUSTs	neutral	no color: a population is a scale, and a larger one is neither good news nor bad. It is the accounting total
Out of scope	neutral	no color: an obligation that never bound Ze is neither an achievement nor a failure, and counting it either way would be a claim
Tested both ways	ok	green at every value: a test pair is the outcome this gate exists to produce, and the share under the label is what says how far Ze has got
One polarity plus reason	ok	green at every value: where no counter-case exists, one polarity IS the complete answer, and a recorded reason is what the gate demands beside it
One polarity, unexcused	ok	green at zero, RED above it: half a proof with no reason for the other half
No test at all	bad	green at zero, RED above it: a binding obligation nothing exercises is a claim with nothing behind it, whether or not a reason is stated
Proven by a recorded break	ok	green at every value: an observed break is the outcome the discrimination gate exists to produce. The denominator is TAGGED UNITS, not obligations, so this share is not one of the parts above
Audit verdicts	warn	RED on the first weak, wrong or unimplemented verdict, amber while a verdict is no longer current or a gated MUST is unjudged, green when every one is judged sound and current

At a glance

Field	Value
Public status	Partial
Enrolment	Enrolled
Requirements	27
Gated MUST-level	17
Obligations that bind Ze	17
Not applicable, so out of scope	0
Declared gaps	3
Gated with no test	0
Nightly-only evidence	0
Test tags	24
Tagged units	24
Recorded audit verdicts	0
Discrimination records	0
Summary	`rfc/short/rfc1994.md`
Requirement shard	`rfc/requirements/rfc1994.md`
RFC text	`rfc/full/rfc1994.txt`

Enrolment

Enrolled: PPP CHAP-MD5 (RFC 1994): authenticator (LNS) + peer (PPPoE client); 5 MET (auth-protocol advertise, Success/Failure per comparison, match->Success, mismatch->Failure, peer Response) + 9 single-polarity positive (Challenge Code 1, changing Identifier/Value, echoed Identifier, repeated-Response tolerance, other-phase discard, Message-independence, interop) + 3 gap (no Challenge retransmit, no repeated-Response replay, no 1-octet secret minimum)

What the public ledger says

Status: Partial

What the ledger says is covered

CHAP-MD5 authenticator (LNS) and peer (PPPoE client): Challenge/Response/Success/Failure codec, per-call 16-octet random Challenge, changing Identifier, MD5(id\|\|secret\|\|challenge) validation via local user table and RADIUS CHAP-Password, LCP Auth-Protocol negotiation.

What the ledger says remains

Three MUST gaps in rfc/short/rfc1994.md: RFC1994-4.1-2 -- one Challenge is sent then the session fails closed on timeout (no retransmission); RFC1994-4.1-9 -- a repeated Response with the current Challenge Identifier is silently dropped rather than re-answered with the prior reply Code (session_run.go); RFC1994-2.3-1 -- the CHAP secret has no 1-octet minimum, so an empty password is accepted.

Coverage

Bucket	Count	What it counts
Positive and negative tests	5	one part of the gated population
Annotated instead of tested	12	one part of the gated population
One polarity only	0	one part of the gated population
No test and no annotation	0	one part of the gated population
Evidence that runs nightly only	0	an overlay: each of these is also counted by the part it falls in
Gated MUST-level requirements	17	every gated MUST falls in exactly one bucket above

Positive and negative tests (5): RFC1994-1-1, RFC1994-4.1-3, RFC1994-4.2-1, RFC1994-4.2-2, RFC1994-4.1-4

Annotated instead of tested (12): RFC1994-4.1-1, RFC1994-4.1-2, RFC1994-4.1-5, RFC1994-4.1-6, RFC1994-4.1-7, RFC1994-4.2-3, RFC1994-4.1-8, RFC1994-4.1-9, RFC1994-4.1-10, RFC1994-2.3-1, RFC1994-4.2-4, RFC1994-1.1-1

Requirements

Requirement	Level	Section	Tests
`RFC1994-1-1`	If authentication is desired, specify Authentication-Protocol Configuration Option during Link Establishment phase (Section 1)
	MUST	1	positive`unit/verifyTestLocalCONFREQAdvertisesAuthMethod` negative`unit/verifyTestAuthProtoRejectClearsMethod`
`RFC1994-4.1-1`	Authenticator must transmit a Challenge packet (Code=1) (Section 4.1)
	MUST	4.1	positive`unit/verifyTestCHAPResponseEmitsEvent` negative`no test`no negative test {single-polarity}: runCHAPAuthPhase always frames and writes a CHAP Challenge with Code=1 as its first wire act, with no must-not-challenge branch (internal/component/l2tp/ppp/chap.go:259-261, :144-146)
`RFC1994-4.1-2`	Additional Challenge packets must be sent until valid Response received or retry counter expires (Section 4.1)
	MUST	4.1	positive`no test`no positive test negative`no test`no negative test {gap}: ze sends exactly one Challenge and, on Response timeout, fails the session closed rather than retransmitting the same Identifier/Value (internal/component/l2tp/ppp/chap.go:257-263 single send; internal/component/l2tp/ppp/auth.go:328-337 timeout calls s.fail with no retransmit)
`RFC1994-4.1-3`	Authenticator must send Success or Failure based on Response comparison (Section 4.1)
	MUST	4.1	positive`unit/verifyTestCHAPResponseEmitsEvent` negative`unit/verifyTestCHAPRejectWritesFailure`
`RFC1994-4.2-1`	If Response Value equals expected value, must transmit Success (Code=3) (Section 4.2)
	MUST	4.2	positive`unit/verifyTestCHAPResponseEmitsEvent` positive`unit/verifyTestLocalAuthCHAPMD5Accept` negative`unit/verifyTestCHAPRejectWritesFailure` negative`unit/verifyTestLocalAuthCHAPMD5Reject`
`RFC1994-4.2-2`	If Response Value does not equal expected value, must transmit Failure (Code=4) (Section 4.2)
	MUST	4.2	positive`unit/verifyTestCHAPRejectWritesFailure` positive`unit/verifyTestLocalAuthCHAPMD5Reject` negative`unit/verifyTestLocalAuthCHAPMD5Accept`
`RFC1994-4.1-4`	Peer must transmit Response (Code=2) whenever Challenge is received (Section 4.1)
	MUST	4.1	positive`unit/verifyTestBuildCHAPResponse` negative`unit/verifyTestBuildCHAPResponseMalformed`
`RFC1994-4.1-5`	Identifier must be changed each time a Challenge is sent (Section 4.1)
	MUST	4.1	positive`unit/verifyTestCHAPIdentifierMonotonic` positive`unit/verifyTestCHAPIdentifierWraps` negative`no test`no negative test {single-polarity}: each runCHAPAuthPhase increments the per-session chapIdentifier before sending, so every new Challenge carries a distinct Identifier, and ze never retransmits a Challenge to form a reuse negative (internal/component/l2tp/ppp/chap.go:254-255)
`RFC1994-4.1-6`	Response Identifier must be copied from the Challenge Identifier (Section 4.1)
	MUST	4.1	positive`unit/verifyTestBuildCHAPResponse` negative`no test`no negative test {single-polarity}: the peer copies the received Challenge's Identifier byte into the Response header, asserted directly with no rejecting counterpart (internal/component/l2tp/pppoeclient/session.go:400)
`RFC1994-4.1-7`	Challenge Value must be changed each time a Challenge is sent (Section 4.1)
	MUST	4.1	positive`unit/verifyTestCHAPChallengeRandom` negative`no test`no negative test {single-polarity}: runCHAPAuthPhase draws a fresh 16-octet value from crypto/rand for every Challenge (internal/component/l2tp/ppp/chap.go:219-225, :248-249)
`RFC1994-4.2-3`	Success/Failure Identifier must be copied from the Response Identifier (Section 4.2)
	MUST	4.2	positive`unit/verifyTestCHAPResponseEmitsEvent` negative`no test`no negative test {single-polarity}: waitCHAPResponse only returns a Response whose Identifier equals the outstanding Challenge Identifier, and runCHAPAuthPhase writes Success/Failure with that same Identifier (internal/component/l2tp/ppp/chap.go:296-298, auth.go:318-323)
`RFC1994-4.1-8`	Authenticator must allow repeated Response packets during Network-Layer Protocol phase (Section 4.1)
	MUST	4.1	positive`unit/verifyTestCHAPRepeatedResponseAfterSuccessKeepsSessionUp` negative`no test`no negative test {single-polarity}: a CHAP Response arriving in the main loop after auth completes hits the frame-dispatch default and is dropped without terminating the session, so repeated Responses are tolerated (internal/component/l2tp/ppp/session_run.go:681-683)
`RFC1994-4.1-9`	Response with current Challenge Identifier must return same reply Code as previously (Section 4.1)
	MUST	4.1	positive`no test`no positive test negative`no test`no negative test {gap}: ze caches no per-Challenge reply Code and does not re-send the prior Success/Failure for a repeated Response; it silently drops it (internal/component/l2tp/ppp/session_run.go:681-683; no reply-Code cache in runCHAPAuthPhase)
`RFC1994-4.1-10`	Response packets received during any other phase must be silently discarded (Section 4.1)
	MUST	4.1	positive`unit/verifyTestCHAPIdentifierMismatchSilentDiscard` negative`no test`no negative test {single-polarity}: outside an active auth-wait a CHAP Response is silently dropped by the frame-dispatch default, and during a wait a Response whose Identifier does not match is silently discarded and the wait continues (internal/component/l2tp/ppp/session_run.go:681-683, auth.go:318-322)
`RFC1994-2.3-1`	Length of the secret must be at least 1 octet (Section 2.3)
	MUST	2.3	positive`no test`no positive test negative`no test`no negative test {gap}: the CHAP shared secret (authlocal user password) has no minimum-length constraint, so an empty password is accepted and fed to the MD5 hash without rejection (internal/component/l2tp/plugins/authlocal/auth.go:94-99; empty password stored in register.go)
`RFC1994-4.2-4`	Message field must not affect operation of the protocol (Section 4.2)
	MUST NOT	4.2	positive`unit/verifyTestCHAPSuccessMessageDoesNotAffectOutcome` negative`no test`no negative test {single-polarity}: the peer branches only on the Success/Failure Code (3 succeed, 4 fail) and never reads or acts on the Message field (internal/component/l2tp/pppoeclient/session.go:270-274)
`RFC1994-1.1-1`	Implementation not including an option must be prepared to interoperate with one that does (Section 1.1)
	MUST	1.1	positive`unit/verifyTestNegotiatePeerAuthProtoAccepted` positive`unit/verifyTestNegotiatePeerAuthProtoRejected` negative`no test`no negative test {single-polarity}: ze negotiates the Auth-Protocol option in both directions -- it accepts a peer-proposed option and handles the peer's Configure-Nak/Reject of it -- so it interoperates whether or not the option is used (internal/component/l2tp/ppp/lcp_options.go:174-183, auth.go:38-68)
`RFC1994-2-1`	Connection should be terminated on authentication failure (Section 2, Section 4.2)
	SHOULD	2	positive`no test`no positive test negative`no test`no negative test
`RFC1994-4.1-11`	Peer should expect Challenge packets during Authentication and Network-Layer Protocol phases (Section 4.1)
	SHOULD	4.1	positive`no test`no positive test negative`no test`no negative test
`RFC1994-2.3-2`	Secret should be at least as large and unguessable as a well-chosen password (Section 2.3)
	SHOULD	2.3	positive`no test`no positive test negative`no test`no negative test
`RFC1994-2.3-3`	Each challenge value should be unique, exhibit global and temporal uniqueness (Section 2.3)
	SHOULD	2.3	positive`no test`no positive test negative`no test`no negative test
`RFC1994-2.3-4`	Each challenge value should be unpredictable (Section 2.3)
	SHOULD	2.3	positive`no test`no positive test negative`no test`no negative test
`RFC1994-1.2-1`	Provide capability of logging silently discarded packets and record in statistics counter (Section 1.2)
	SHOULD	1.2	positive`no test`no positive test negative`no test`no negative test
`RFC1994-x-1`	Secret should not be the same in both directions (Security Considerations)
	SHOULD NOT	x	positive`no test`no positive test negative`no test`no negative test
`RFC1994-4.1-12`	Challenge may be sent at any time during Network-Layer Protocol phase (Section 4.1)
	MAY	4.1	positive`no test`no positive test negative`no test`no negative test
`RFC1994-4.1-13`	Name may contain ASCII strings or ASN.1 identifiers (Section 4.1)
	MAY	4.1	positive`no test`no positive test negative`no test`no negative test
`RFC1994-4.1-14`	Success/Failure Message may differ between replies for the same Identifier (Section 4.1)
	MAY	4.1	positive`no test`no positive test negative`no test`no negative test

Gaps and untested MUSTs

Requirement	State	Reason
`RFC1994-4.1-2` Additional Challenge packets must be sent until valid Response received or retry counter expires (Section 4.1)	{gap}, no test	ze sends exactly one Challenge and, on Response timeout, fails the session closed rather than retransmitting the same Identifier/Value (internal/component/l2tp/ppp/chap.go:257-263 single send; internal/component/l2tp/ppp/auth.go:328-337 timeout calls s.fail with no retransmit)
`RFC1994-4.1-9` Response with current Challenge Identifier must return same reply Code as previously (Section 4.1)	{gap}, no test	ze caches no per-Challenge reply Code and does not re-send the prior Success/Failure for a repeated Response; it silently drops it (internal/component/l2tp/ppp/session_run.go:681-683; no reply-Code cache in runCHAPAuthPhase)
`RFC1994-2.3-1` Length of the secret must be at least 1 octet (Section 2.3)	{gap}, no test	the CHAP shared secret (authlocal user password) has no minimum-length constraint, so an empty password is accepted and fed to the MD5 hash without rejection (internal/component/l2tp/plugins/authlocal/auth.go:94-99; empty password stored in register.go)

Proof state

A tagged unit reads unproven where no discrimination record exists for it: nothing in this tree has been observed to break it, so the claim its tag makes is unproven.

`RFC1994-1-1`

If authentication is desired, specify Authentication-Protocol Configuration Option during Link Establishment phase (Section 1)