修复了一些已知问题

backend/internal/kvm/kvm.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/rand"
+	"crypto/sha256"
 	"encoding/base64"
 	"encoding/binary"
 	"encoding/hex"
@@ -738,10 +739,14 @@ func (m *Manager) ResetSSHPassword(id int, password string) (string, error) {
 	if err := m.EnsureSSH(id); err != nil {
 		return "", err
 	}
+	chpasswdInput, err := chpasswdStdin("root", password)
+	if err != nil {
+		return "", err
+	}
 	client, err := ssh.Dial("tcp", net.JoinHostPort(c.IP, "22"), &ssh.ClientConfig{
 		User:            "root",
 		Auth:            []ssh.AuthMethod{ssh.Password(c.SSHPassword)},
-		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+		HostKeyCallback: kvmHostKeyCallback(c),
 		Timeout:         8 * time.Second,
 	})
 	if err != nil {
@@ -753,8 +758,8 @@ func (m *Manager) ResetSSHPassword(id int, password string) (string, error) {
 		return "", err
 	}
 	defer session.Close()
-	cmd := fmt.Sprintf("printf 'root:%s\\n' | chpasswd", shellQuote(password))
-	if output, err := session.CombinedOutput(cmd); err != nil {
+	session.Stdin = bytes.NewReader(chpasswdInput)
+	if output, err := session.CombinedOutput("chpasswd"); err != nil {
 		return "", fmt.Errorf("failed to reset password: %v, output: %s", err, string(output))
 	}
 	c.SSHPassword = password
@@ -2224,7 +2229,7 @@ func (m *Manager) EnsureSSH(id int) error {
 		client, err := ssh.Dial("tcp", net.JoinHostPort(c.IP, "22"), &ssh.ClientConfig{
 			User:            "root",
 			Auth:            []ssh.AuthMethod{ssh.Password(c.SSHPassword)},
-			HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+			HostKeyCallback: kvmHostKeyCallback(c),
 			Timeout:         8 * time.Second,
 		})
 		if err != nil {
@@ -3190,7 +3195,7 @@ func (m *Manager) applyGuestIPv6OverSSH(c *config.Container) error {
 	client, err := ssh.Dial("tcp", net.JoinHostPort(c.IP, "22"), &ssh.ClientConfig{
 		User:            "root",
 		Auth:            []ssh.AuthMethod{ssh.Password(c.SSHPassword)},
-		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+		HostKeyCallback: kvmHostKeyCallback(c),
 		Timeout:         8 * time.Second,
 	})
 	if err != nil {
@@ -3377,6 +3382,46 @@ func shellQuote(value string) string {
 	return "'" + strings.ReplaceAll(value, "'", "'\"'\"'") + "'"
 }
 
+func chpasswdStdin(username, password string) ([]byte, error) {
+	if username == "" || strings.ContainsAny(username, ":\n\r") {
+		return nil, fmt.Errorf("invalid chpasswd username")
+	}
+	if strings.ContainsAny(password, "\n\r") {
+		return nil, fmt.Errorf("password cannot contain newlines")
+	}
+	return []byte(username + ":" + password + "\n"), nil
+}
+
+func kvmHostKeyCallback(c *config.Container) ssh.HostKeyCallback {
+	return func(hostname string, remote net.Addr, key ssh.PublicKey) error {
+		return verifyKVMHostKey(c, key, config.SaveConfig)
+	}
+}
+
+func verifyKVMHostKey(c *config.Container, key ssh.PublicKey, save func() error) error {
+	if c == nil {
+		return fmt.Errorf("KVM container is nil")
+	}
+	fingerprint := sshHostKeyFingerprint(key)
+	if c.SSHHostKey != "" && c.SSHHostKey != fingerprint {
+		return fmt.Errorf("KVM SSH host key mismatch")
+	}
+	if c.SSHHostKey == "" {
+		c.SSHHostKey = fingerprint
+		if save != nil {
+			if err := save(); err != nil {
+				return fmt.Errorf("failed to save KVM SSH host key: %v", err)
+			}
+		}
+	}
+	return nil
+}
+
+func sshHostKeyFingerprint(key ssh.PublicKey) string {
+	sum := sha256.Sum256(key.Marshal())
+	return hex.EncodeToString(sum[:])
+}
+
 func allocateDefaultEqualPorts(c *config.Container, count int) []int {
 	if count <= 0 {
 		return nil

backend/internal/kvm/kvm_test.go

@@ -0,0 +1,95 @@
+package kvm
+
+import (
+	"crypto/ed25519"
+	"crypto/rand"
+	"reflect"
+	"testing"
+
+	"clicd/internal/config"
+
+	"golang.org/x/crypto/ssh"
+)
+
+func TestChpasswdStdinPreservesShellMetacharacters(t *testing.T) {
+	password := `pa'";$(touch /tmp/pwned); echo #\\word`
+	got, err := chpasswdStdin("root", password)
+	if err != nil {
+		t.Fatalf("chpasswdStdin returned error: %v", err)
+	}
+
+	want := []byte("root:" + password + "\n")
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("chpasswdStdin = %#v, want %#v", got, want)
+	}
+}
+
+func TestChpasswdStdinRejectsNewlines(t *testing.T) {
+	tests := []struct {
+		name     string
+		username string
+		password string
+	}{
+		{name: "username newline", username: "root\nadmin", password: "safe"},
+		{name: "username colon", username: "root:admin", password: "safe"},
+		{name: "password newline", username: "root", password: "safe\nroot:evil"},
+		{name: "password carriage return", username: "root", password: "safe\rroot:evil"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			if _, err := chpasswdStdin(tc.username, tc.password); err == nil {
+				t.Fatal("chpasswdStdin returned nil error")
+			}
+		})
+	}
+}
+
+func TestVerifyKVMHostKeyCapturesAndRejectsMismatch(t *testing.T) {
+	key1 := testSSHPublicKey(t)
+	key2 := testSSHPublicKey(t)
+
+	saves := 0
+	c := &config.Container{}
+	save := func() error {
+		saves++
+		return nil
+	}
+
+	if err := verifyKVMHostKey(c, key1, save); err != nil {
+		t.Fatalf("first host key verification returned error: %v", err)
+	}
+	if c.SSHHostKey == "" {
+		t.Fatal("first host key verification did not capture fingerprint")
+	}
+	if c.SSHHostKey != sshHostKeyFingerprint(key1) {
+		t.Fatalf("captured fingerprint = %q, want %q", c.SSHHostKey, sshHostKeyFingerprint(key1))
+	}
+	if saves != 1 {
+		t.Fatalf("save count = %d, want 1", saves)
+	}
+
+	if err := verifyKVMHostKey(c, key1, save); err != nil {
+		t.Fatalf("same host key verification returned error: %v", err)
+	}
+	if saves != 1 {
+		t.Fatalf("save count after same key = %d, want 1", saves)
+	}
+
+	if err := verifyKVMHostKey(c, key2, save); err == nil {
+		t.Fatal("mismatched host key verification returned nil error")
+	}
+}
+
+func testSSHPublicKey(t *testing.T) ssh.PublicKey {
+	t.Helper()
+	_, privateKey, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	signer, err := ssh.NewSignerFromKey(privateKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return signer.PublicKey()
+}