lib/ssh: set client config HostKeyAlgorithms from known_hosts files

There is an issue with current SSH client implementation.
Given a single host public key in the known_hosts file,

   host ssh-ed25519 key...

Calling ssh.Dial(`tcp`, "host", ...) will return an error

   knownhosts: key mismatch

from [handshakeTransport.enterKeyExchange], because only key
"mlkem768x25519-sha256" is checked on the client side.

This changes add DB interface for knownhosts that have two methods:

- HostKeyAlgorithms: return the host key that matches in known_hosts
  based on the "host" name or address for
  [ssh.ClientConfig.HostKeyAlgorithms].

- HostKeyCallback: return the ssh.HostKeyCallback for
  [ssh.ClientConfig.HostKeyCallback].

3 files changed, 22 insertions, 13 deletions

diff --git a/go.mod b/go.mod
index 73d814a0..2971b242 100644
--- a/go.mod
+++ b/go.mod
@@ -10,7 +10,7 @@ require (
 	golang.org/x/exp v0.0.0-20260218203240-3dfff04db8fa
 	golang.org/x/net v0.51.0
 	golang.org/x/sys v0.42.0
-	golang.org/x/term v0.40.0
+	golang.org/x/term v0.41.0
 	golang.org/x/tools v0.42.0
 )
 
@@ -20,6 +20,6 @@ require (
 	golang.org/x/sync v0.20.0 // indirect
 )
 
-//replace golang.org/x/crypto => ../go-x-crypto
+replace golang.org/x/crypto => git.sr.ht/~shulhan/go-x-crypto v0.49.1-0.20260326231004-e6291d138282
 
 //replace golang.org/x/term => ../../../golang.org/x/term
diff --git a/go.sum b/go.sum
index 8bfe99f8..4d66498d 100644
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,7 @@
+git.sr.ht/~shulhan/go-x-crypto v0.49.1-0.20260326231004-e6291d138282 h1:tiv3enyeoZwbzASD7bHS5pE/LPuSchkkE0U6mzIlM8g=
+git.sr.ht/~shulhan/go-x-crypto v0.49.1-0.20260326231004-e6291d138282/go.mod h1:ErX4dUh2UM+CFYiXZRTcMpEcN8b/1gxEuv3nODoYtCA=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
-golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
-golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
 golang.org/x/exp v0.0.0-20260218203240-3dfff04db8fa h1:Zt3DZoOFFYkKhDT3v7Lm9FDMEV06GpzjG2jrqW+QTE0=
 golang.org/x/exp v0.0.0-20260218203240-3dfff04db8fa/go.mod h1:K79w1Vqn7PoiZn+TkNpx3BUWUQksGO3JcVX6qIjytmA=
 golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
@@ -12,7 +12,7 @@ golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
 golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
 golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/term v0.40.0 h1:36e4zGLqU4yhjlmxEaagx2KuYbJq3EwY8K943ZsHcvg=
-golang.org/x/term v0.40.0/go.mod h1:w2P8uVp06p2iyKKuvXIm7N/y0UCRt3UfJTfZ7oOpglM=
+golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
+golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
 golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
 golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=
diff --git a/lib/ssh/client.go b/lib/ssh/client.go
index cff1c9a9..e712c516 100644
--- a/lib/ssh/client.go
+++ b/lib/ssh/client.go
@@ -87,7 +87,7 @@ func NewClientInteractive(section *sshconfig.Section) (cl *Client, err error) {
 		remoteAddr: fmt.Sprintf(`%s:%s`, section.Hostname(), section.Port()),
 	}
 
-	err = cl.setConfigHostKeyCallback()
+	err = cl.setConfigHostKey()
 	if err != nil {
 		return nil, fmt.Errorf(`%s: %w`, logp, err)
 	}
@@ -134,13 +134,14 @@ func NewClientInteractive(section *sshconfig.Section) (cl *Client, err error) {
 	return cl, nil
 }
 
-// setConfigHostKeyCallback set the [sshconfig.HostKeyCallback] based on the
-// UserKnownHostsFile in the Section.
+// setConfigHostKey sets the [ssh.ClientConfig.HostKeyCallback] and
+// [ssh.ClientConfig.HostKeyAlgorithms] based on the UserKnownHostsFile in the
+// Section.
 // If one of the UserKnownHostsFile set to "none" it will use
 // [ssh.InsecureIgnoreHostKey].
-func (cl *Client) setConfigHostKeyCallback() (err error) {
+func (cl *Client) setConfigHostKey() (err error) {
 	var (
-		logp           = `setConfigHostKeyCallback`
+		logp           = `setConfigHostKey`
 		userKnownHosts = cl.section.UserKnownHostsFile()
 
 		knownHosts string
@@ -166,11 +167,19 @@ func (cl *Client) setConfigHostKeyCallback() (err error) {
 		}
 	}
 
-	cl.config.HostKeyCallback, err = knownhosts.New(cl.listKnownHosts...)
+	knownHostsDB, err := knownhosts.NewDB(cl.listKnownHosts...)
 	if err != nil {
 		return fmt.Errorf(`%s: %w`, logp, err)
 	}
 
+	cl.config.HostKeyAlgorithms, err = knownHostsDB.HostKeyAlgorithms(cl.remoteAddr)
+	if err != nil {
+		return fmt.Errorf(`%s: %w`, logp, err)
+	}
+	if len(cl.config.HostKeyAlgorithms) == 0 {
+		return fmt.Errorf(`%s: no matching known_hosts for %s`, logp, cl.remoteAddr)
+	}
+	cl.config.HostKeyCallback = knownHostsDB.HostKeyCallback()
 	return nil
 }
 
@@ -250,7 +259,7 @@ func (cl *Client) dialWithPrivateKeys(sshAgent agent.ExtendedAgent) (err error)
 		err = cl.dialError(logp, err)
 	}
 	if err != nil {
-		return err
+		return fmt.Errorf(`%s: %w`, logp, err)
 	}
 	if cl.Client == nil {
 		// None of the private key can connect to remote address.