[chore]: Bump golang.org/x/net from 0.15.0 to 0.16.0 (#2260)

Bumps [golang.org/x/net](https://github.com/golang/net) from 0.15.0 to 0.16.0.
- [Commits](https://github.com/golang/net/compare/v0.15.0...v0.16.0)

---
updated-dependencies:
- dependency-name: golang.org/x/net
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

1 files changed, 30 insertions, 14 deletions

diff --git a/vendor/golang.org/x/crypto/ssh/handshake.go b/vendor/golang.org/x/crypto/ssh/handshake.go
index 07a1843e0..70a7369ff 100644
--- a/vendor/golang.org/x/crypto/ssh/handshake.go
+++ b/vendor/golang.org/x/crypto/ssh/handshake.go
@@ -461,19 +461,24 @@ func (t *handshakeTransport) sendKexInit() error {
 	isServer := len(t.hostKeys) > 0
 	if isServer {
 		for _, k := range t.hostKeys {
-			// If k is an AlgorithmSigner, presume it supports all signature algorithms
-			// associated with the key format. (Ideally AlgorithmSigner would have a
-			// method to advertise supported algorithms, but it doesn't. This means that
-			// adding support for a new algorithm is a breaking change, as we will
-			// immediately negotiate it even if existing implementations don't support
-			// it. If that ever happens, we'll have to figure something out.)
-			// If k is not an AlgorithmSigner, we can only assume it only supports the
-			// algorithms that matches the key format. (This means that Sign can't pick
-			// a different default.)
+			// If k is a MultiAlgorithmSigner, we restrict the signature
+			// algorithms. If k is a AlgorithmSigner, presume it supports all
+			// signature algorithms associated with the key format. If k is not
+			// an AlgorithmSigner, we can only assume it only supports the
+			// algorithms that matches the key format. (This means that Sign
+			// can't pick a different default).
 			keyFormat := k.PublicKey().Type()
-			if _, ok := k.(AlgorithmSigner); ok {
+
+			switch s := k.(type) {
+			case MultiAlgorithmSigner:
+				for _, algo := range algorithmsForKeyFormat(keyFormat) {
+					if contains(s.Algorithms(), underlyingAlgo(algo)) {
+						msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algo)
+					}
+				}
+			case AlgorithmSigner:
 				msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algorithmsForKeyFormat(keyFormat)...)
-			} else {
+			default:
 				msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, keyFormat)
 			}
 		}
@@ -642,16 +647,20 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
 
 	// On the server side, after the first SSH_MSG_NEWKEYS, send a SSH_MSG_EXT_INFO
 	// message with the server-sig-algs extension if the client supports it. See
-	// RFC 8308, Sections 2.4 and 3.1.
+	// RFC 8308, Sections 2.4 and 3.1, and [PROTOCOL], Section 1.9.
 	if !isClient && firstKeyExchange && contains(clientInit.KexAlgos, "ext-info-c") {
 		extInfo := &extInfoMsg{
-			NumExtensions: 1,
-			Payload:       make([]byte, 0, 4+15+4+len(supportedPubKeyAuthAlgosList)),
+			NumExtensions: 2,
+			Payload:       make([]byte, 0, 4+15+4+len(supportedPubKeyAuthAlgosList)+4+16+4+1),
 		}
 		extInfo.Payload = appendInt(extInfo.Payload, len("server-sig-algs"))
 		extInfo.Payload = append(extInfo.Payload, "server-sig-algs"...)
 		extInfo.Payload = appendInt(extInfo.Payload, len(supportedPubKeyAuthAlgosList))
 		extInfo.Payload = append(extInfo.Payload, supportedPubKeyAuthAlgosList...)
+		extInfo.Payload = appendInt(extInfo.Payload, len("ping@openssh.com"))
+		extInfo.Payload = append(extInfo.Payload, "ping@openssh.com"...)
+		extInfo.Payload = appendInt(extInfo.Payload, 1)
+		extInfo.Payload = append(extInfo.Payload, "0"...)
 		if err := t.conn.writePacket(Marshal(extInfo)); err != nil {
 			return err
 		}
@@ -685,9 +694,16 @@ func (a algorithmSignerWrapper) SignWithAlgorithm(rand io.Reader, data []byte, a
 
 func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner {
 	for _, k := range hostKeys {
+		if s, ok := k.(MultiAlgorithmSigner); ok {
+			if !contains(s.Algorithms(), underlyingAlgo(algo)) {
+				continue
+			}
+		}
+
 		if algo == k.PublicKey().Type() {
 			return algorithmSignerWrapper{k}
 		}
+
 		k, ok := k.(AlgorithmSigner)
 		if !ok {
 			continue