ddn.net.ssh.kexinit

SSH_MSG_KEXINIT construction, parsing, and algorithm negotiation (RFC 4253 section 7.1, RFC 8308, strict KEX).

The client appends the RFC 8308 ext-info-c indicator and the strict-KEX marker to its key-exchange list; neither is ever selectable as the actual algorithm. Negotiation picks the first client preference the server also lists, skipping indicator names, and fails closed when any category has no match.

var CURVE25519_SHA256_LIBSSH

enum SshKexIndicators

struct SshKexInit SshNegotiationResult

fn buildKexInitPayload cipherNeedsMac containsName firstHostKeyAlgorithm firstKexAlgorithm isCurve25519Kex isIndicator matchSkippingIndicators negotiate negotiateKexName parseKexInitPayload parseRoundTrip serverAdvertisesStrictKex

Types 3

enumSshKexIndicators

Pseudo-algorithm indicators carried inside kex_algorithms.

extInfoClient = "ext-info-c"RFC 8308: client wants to receive SSH_MSG_EXT_INFO

extInfoServer = "ext-info-s"RFC 8308: server is prepared to receive SSH_MSG_EXT_INFO

strictServer = "kex-strict-c-v00@openssh.com"Strict KEX: client asks the server to enforce strict behaviour

strictClient = "kex-strict-s-v00@openssh.com"Strict KEX: server agrees to enforce strict behaviour

structSshKexInit

A parsed SSH_MSG_KEXINIT.

rawPayload preserves the exact payload bytes (including the message-number byte) for the exchange-hash transcript.

Fields

ubyte[16] cookie

string[] kex

string[] hostKey

string[] cipherC2S

string[] cipherS2C

string[] macC2S

string[] macS2C

string[] compressionC2S

string[] compressionS2C

string[] languagesC2S

string[] languagesS2C

bool firstKexPacketFollows

const(ubyte)[] rawPayload

structSshNegotiationResult

Outcome of algorithm negotiation plus extension signalling.

Fields

SshNegotiatedAlgorithms algorithms

bool strictKex

bool peerExpectsExtInfoFromUs

Functions 13

fnbool isCurve25519Kex(scope const(char)[] name) pure nothrow @safe @nogcWhether a KEX name selects the curve25519-sha256 method.

ubyte[] buildKexInitPayload(const  SshAlgorithmPreferences prefs,
       in  ubyte[16]  cookie,  bool  strictKex =  true)

@safeBuilds the client's KEXINIT payload.

fnSshKexInit parseKexInitPayload(const(ubyte)[] payload) @safeParses a KEXINIT payload.

SshNegotiationResult negotiate(const  SshKexInit client,
       const  SshKexInit server)

@safeNegotiates algorithms from the client's and server's KEXINIT.

fnbool serverAdvertisesStrictKex(scope const SshKexInit server) @safe pure nothrowWhether a server KEXINIT advertises the strict-KEX server marker.

string negotiateKexName(scope  const  SshKexInit client,
       scope  const  SshKexInit server)

@safeNegotiates only the key-exchange name from both KEXINITs.

fnstring firstKexAlgorithm(scope const SshKexInit server) @safe pure nothrowReturns the server's actual guessed key exchange.

fnstring firstHostKeyAlgorithm(scope const SshKexInit server) @safe pure nothrowReturns the server host-key algorithm covered by a speculative first key-exchange packet.

private fnbool cipherNeedsMac(string cipher) @safe pure nothrow

private fnbool isIndicator(string name) @safe pure nothrow

private fnbool containsName(scope const string[] list, string name) @safe pure nothrow

private fn

string matchSkippingIndicators(scope  const  string[]  client,
          scope  const  string[]  server)

@safe

private fn

SshKexInit parseRoundTrip(const  SshAlgorithmPreferences prefs,
       bool  strictKex =  true)

@safe

Variables 1

enumvarCURVE25519_SHA256_LIBSSH = "curve25519-sha256@libssh.org"

Compatibility alias selecting the same key exchange as curve25519-sha256 (OpenSSH and libssh wire name).