init

internal/keymgr/pack.go

@@ -0,0 +1,89 @@
+package keymgr
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"ssh-access-tui/internal/model"
+)
+
+// BuildResult describes one user's finished delivery archive.
+type BuildResult struct {
+	Username      string
+	ArchivePath   string
+	Fingerprint   string
+	PublicKeyLine string // capture before the scratch dir (and its .pub file) is wiped
+}
+
+// BuildUserArchive generates a fresh keypair for username, writes the
+// client config and Windows instructions alongside it in a scratch
+// directory, packs everything into a single AES-256-encrypted 7z archive
+// under outDir, and then wipes the scratch directory (including the
+// plaintext private key) from disk. password is shared across one export
+// batch and must be communicated to the recipient out-of-band.
+func BuildUserArchive(scratchDir, outDir, jumpHost string, jumpPort int, username, password string, hosts []model.Host) (*BuildResult, error) {
+	userScratch := filepath.Join(scratchDir, username)
+	if err := os.MkdirAll(userScratch, 0o700); err != nil {
+		return nil, fmt.Errorf("create scratch dir: %w", err)
+	}
+	defer Wipe(userScratch)
+
+	kp, err := GeneratePair(userScratch, username)
+	if err != nil {
+		return nil, fmt.Errorf("generate keypair: %w", err)
+	}
+	keyFileName := filepath.Base(kp.PrivateKeyPath)
+
+	cfg := RenderClientConfig(jumpHost, jumpPort, username, keyFileName, hosts)
+	if err := os.WriteFile(filepath.Join(userScratch, "config"), []byte(cfg), 0o600); err != nil {
+		return nil, fmt.Errorf("write config: %w", err)
+	}
+
+	instr := RenderInstructions(username, jumpHost, keyFileName, hosts)
+	if err := os.WriteFile(filepath.Join(userScratch, "INSTRUCTIONS.txt"), []byte(instr), 0o600); err != nil {
+		return nil, fmt.Errorf("write instructions: %w", err)
+	}
+
+	if err := os.MkdirAll(outDir, 0o750); err != nil {
+		return nil, fmt.Errorf("create output dir: %w", err)
+	}
+	archivePath := filepath.Join(outDir, username+"_ssh_access.7z")
+	_ = os.Remove(archivePath) // 7z refuses to overwrite silently-appends; start clean
+
+	cmd := exec.Command("7z", "a",
+		"-p"+password,
+		"-mhe=on", // encrypt file names/headers too, not just contents
+		"-mx=9",
+		archivePath,
+		filepath.Join(userScratch, keyFileName),
+		filepath.Join(userScratch, keyFileName+".pub"),
+		filepath.Join(userScratch, "config"),
+		filepath.Join(userScratch, "INSTRUCTIONS.txt"),
+	)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return nil, fmt.Errorf("7z: %w: %s", err, out)
+	}
+
+	return &BuildResult{
+		Username:      username,
+		ArchivePath:   archivePath,
+		Fingerprint:   kp.Fingerprint,
+		PublicKeyLine: kp.PublicKeyLine,
+	}, nil
+}
+
+// Wipe securely removes a scratch directory (best-effort shred of file
+// contents, then unlink) so the private key does not linger in free disk
+// space or in any backup that might sweep the tool's working directory.
+func Wipe(dir string) {
+	_ = filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil || info.IsDir() {
+			return nil
+		}
+		_ = exec.Command("shred", "-u", "-n", "1", path).Run()
+		return nil
+	})
+	_ = os.RemoveAll(dir)
+}