first pass at a certificate store

4 files changed, 387 insertions, 0 deletions

diff --git a/server/store/mem.go b/server/store/mem.go
new file mode 100644
index 0000000..8b78e27
--- /dev/null
+++ b/server/store/mem.go
@@ -0,0 +1,86 @@
+package store
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"golang.org/x/crypto/ssh"
+)
+
+type memoryStore struct {
+	sync.Mutex
+	certs map[string]*CertRecord
+}
+
+func (ms *memoryStore) Get(id string) (*CertRecord, error) {
+	ms.Lock()
+	defer ms.Unlock()
+	r, ok := ms.certs[id]
+	if !ok {
+		return nil, fmt.Errorf("unknown cert %s", id)
+	}
+	return r, nil
+}
+
+func (ms *memoryStore) SetCert(cert *ssh.Certificate) error {
+	return ms.SetRecord(parseCertificate(cert))
+}
+
+func (ms *memoryStore) SetRecord(record *CertRecord) error {
+	ms.Lock()
+	defer ms.Unlock()
+	ms.certs[record.KeyID] = record
+	return nil
+}
+
+func (ms *memoryStore) List() ([]*CertRecord, error) {
+	var records []*CertRecord
+	ms.Lock()
+	defer ms.Unlock()
+	for _, value := range ms.certs {
+		records = append(records, value)
+	}
+	return records, nil
+}
+
+func (ms *memoryStore) Revoke(id string) error {
+	r, err := ms.Get(id)
+	if err != nil {
+		return err
+	}
+	r.Revoked = true
+	ms.SetRecord(r)
+	return nil
+}
+
+func (ms *memoryStore) GetRevoked() ([]*CertRecord, error) {
+	var revoked []*CertRecord
+	all, _ := ms.List()
+	for _, r := range all {
+		if r.Revoked && uint64(time.Now().UTC().Unix()) <= r.Expires {
+			revoked = append(revoked, r)
+		}
+	}
+	return revoked, nil
+}
+
+func (ms *memoryStore) Close() error {
+	ms.Lock()
+	defer ms.Unlock()
+	ms.certs = nil
+	return nil
+}
+
+func (ms *memoryStore) clear() {
+	for k := range ms.certs {
+		delete(ms.certs, k)
+	}
+}
+
+// NewMemoryStore returns an in-memory CertStorer.
+func NewMemoryStore() CertStorer {
+	return &memoryStore{
+		certs: make(map[string]*CertRecord),
+	}
+}
diff --git a/server/store/mysql.go b/server/store/mysql.go
new file mode 100644
index 0000000..b108fdc
--- /dev/null
+++ b/server/store/mysql.go
@@ -0,0 +1,160 @@
+package store
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+
+	"golang.org/x/crypto/ssh"
+
+	"github.com/go-sql-driver/mysql"
+)
+
+type mysqlDB struct {
+	conn *sql.DB
+
+	get     *sql.Stmt
+	set     *sql.Stmt
+	list    *sql.Stmt
+	revoke  *sql.Stmt
+	revoked *sql.Stmt
+}
+
+func parseConfig(config string) string {
+	s := strings.Split(config, ":")
+	if len(s) == 4 {
+		s = append(s, "3306")
+	}
+	_, user, passwd, host, port := s[0], s[1], s[2], s[3], s[4]
+	c := &mysql.Config{
+		User:   user,
+		Passwd: passwd,
+		Net:    "tcp",
+		Addr:   fmt.Sprintf("%s:%s", host, port),
+		DBName: "certs",
+	}
+	return c.FormatDSN()
+}
+
+// NewMySQLStore returns a MySQL CertStorer.
+func NewMySQLStore(config string) (CertStorer, error) {
+	conn, err := sql.Open("mysql", parseConfig(config))
+	if err != nil {
+		return nil, fmt.Errorf("mysql: could not get a connection: %v", err)
+	}
+	if err := conn.Ping(); err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("mysql: could not establish a good connection: %v", err)
+	}
+
+	db := &mysqlDB{
+		conn: conn,
+	}
+
+	if db.set, err = conn.Prepare("INSERT INTO issued_certs (key_id, principals, created_at, expires_at, raw_key) VALUES (?, ?, ?, ?, ?) ON DUPLICATE KEY UPDATE key_id = VALUES(key_id), principals = VALUES(principals), created_at = VALUES(created_at), expires_at = VALUES(expires_at), raw_key = VALUES(raw_key)"); err != nil {
+		return nil, fmt.Errorf("mysql: prepare set: %v", err)
+	}
+	if db.get, err = conn.Prepare("SELECT * FROM issued_certs WHERE key_id = ?"); err != nil {
+		return nil, fmt.Errorf("mysql: prepare get: %v", err)
+	}
+	if db.list, err = conn.Prepare("SELECT * FROM issued_certs"); err != nil {
+		return nil, fmt.Errorf("mysql: prepare list: %v", err)
+	}
+	if db.revoke, err = conn.Prepare("UPDATE issued_certs SET revoked = TRUE WHERE key_id = ?"); err != nil {
+		return nil, fmt.Errorf("mysql: prepare revoke: %v", err)
+	}
+	if db.revoked, err = conn.Prepare("SELECT * FROM issued_certs WHERE revoked = TRUE AND ? <= expires_at"); err != nil {
+		return nil, fmt.Errorf("mysql: prepare revoked: %v", err)
+	}
+	return db, nil
+}
+
+// rowScanner is implemented by sql.Row and sql.Rows
+type rowScanner interface {
+	Scan(dest ...interface{}) error
+}
+
+func scanCert(s rowScanner) (*CertRecord, error) {
+	var (
+		keyID      sql.NullString
+		principals sql.NullString
+		createdAt  sql.NullInt64
+		expires    sql.NullInt64
+		revoked    sql.NullBool
+		raw        sql.NullString
+	)
+	if err := s.Scan(&keyID, &principals, &createdAt, &expires, &revoked, &raw); err != nil {
+		return nil, err
+	}
+	var p []string
+	if err := json.Unmarshal([]byte(principals.String), &p); err != nil {
+		return nil, err
+	}
+	return &CertRecord{
+		KeyID:      keyID.String,
+		Principals: p,
+		CreatedAt:  uint64(createdAt.Int64),
+		Expires:    uint64(expires.Int64),
+		Revoked:    revoked.Bool,
+		Raw:        raw.String,
+	}, nil
+}
+
+func (db *mysqlDB) Get(id string) (*CertRecord, error) {
+	return scanCert(db.get.QueryRow(id))
+}
+
+func (db *mysqlDB) SetCert(cert *ssh.Certificate) error {
+	return db.SetRecord(parseCertificate(cert))
+}
+
+func (db *mysqlDB) SetRecord(rec *CertRecord) error {
+	principals, err := json.Marshal(rec.Principals)
+	if err != nil {
+		return err
+	}
+	_, err = db.set.Exec(rec.KeyID, string(principals), rec.CreatedAt, rec.Expires, rec.Raw)
+	return err
+}
+
+func (db *mysqlDB) List() ([]*CertRecord, error) {
+	var recs []*CertRecord
+	rows, _ := db.list.Query()
+	defer rows.Close()
+	for rows.Next() {
+		cert, err := scanCert(rows)
+		if err != nil {
+			return nil, err
+		}
+		recs = append(recs, cert)
+	}
+	return recs, nil
+}
+
+func (db *mysqlDB) Revoke(id string) error {
+	_, err := db.revoke.Exec(id)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (db *mysqlDB) GetRevoked() ([]*CertRecord, error) {
+	var recs []*CertRecord
+	rows, _ := db.revoked.Query(time.Now().UTC().Unix())
+	defer rows.Close()
+	for rows.Next() {
+		cert, err := scanCert(rows)
+		if err != nil {
+			return nil, err
+		}
+		recs = append(recs, cert)
+	}
+	return recs, nil
+}
+
+func (db *mysqlDB) Close() error {
+	return db.conn.Close()
+}
diff --git a/server/store/store.go b/server/store/store.go
new file mode 100644
index 0000000..ad4922a
--- /dev/null
+++ b/server/store/store.go
@@ -0,0 +1,39 @@
+package store
+
+import (
+	"golang.org/x/crypto/ssh"
+
+	"github.com/nsheridan/cashier/server/certutil"
+)
+
+// CertStorer records issued certs in a persistent store for audit and
+// revocation purposes.
+type CertStorer interface {
+	Get(id string) (*CertRecord, error)
+	SetCert(cert *ssh.Certificate) error
+	SetRecord(record *CertRecord) error
+	List() ([]*CertRecord, error)
+	Revoke(id string) error
+	GetRevoked() ([]*CertRecord, error)
+	Close() error
+}
+
+// A CertRecord is a representation of a ssh certificate used by a CertStorer.
+type CertRecord struct {
+	KeyID      string
+	Principals []string
+	CreatedAt  uint64
+	Expires    uint64
+	Revoked    bool
+	Raw        string
+}
+
+func parseCertificate(cert *ssh.Certificate) *CertRecord {
+	return &CertRecord{
+		KeyID:      cert.KeyId,
+		Principals: cert.ValidPrincipals,
+		CreatedAt:  cert.ValidAfter,
+		Expires:    cert.ValidBefore,
+		Raw:        certutil.GetPublicKey(cert),
+	}
+}
diff --git a/server/store/store_test.go b/server/store/store_test.go
new file mode 100644
index 0000000..d3aa3c1
--- /dev/null
+++ b/server/store/store_test.go
@@ -0,0 +1,102 @@
+package store
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/nsheridan/cashier/testdata"
+	"github.com/stretchr/testify/assert"
+
+	"golang.org/x/crypto/ssh"
+)
+
+func TestParseCertificate(t *testing.T) {
+	a := assert.New(t)
+	now := uint64(time.Now().Unix())
+	r, _ := rsa.GenerateKey(rand.Reader, 1024)
+	pub, _ := ssh.NewPublicKey(r.Public())
+	c := &ssh.Certificate{
+		KeyId:           "id",
+		ValidPrincipals: []string{"principal"},
+		ValidBefore:     now,
+		CertType:        ssh.UserCert,
+		Key:             pub,
+	}
+	s, _ := ssh.NewSignerFromKey(r)
+	c.SignCert(rand.Reader, s)
+	rec := parseCertificate(c)
+
+	a.Equal(c.KeyId, rec.KeyID)
+	a.Equal(c.ValidPrincipals, rec.Principals)
+	a.Equal(c.ValidBefore, rec.Expires)
+	a.Equal(c.ValidAfter, rec.CreatedAt)
+}
+
+func testStore(t *testing.T, db CertStorer) {
+	defer db.Close()
+
+	ids := []string{"a", "b"}
+	for _, id := range ids {
+		r := &CertRecord{
+			KeyID:   id,
+			Expires: uint64(time.Now().UTC().Unix()) - 10,
+		}
+		if err := db.SetRecord(r); err != nil {
+			t.Error(err)
+		}
+	}
+	recs, err := db.List()
+	if err != nil {
+		t.Error(err)
+	}
+	if len(recs) != len(ids) {
+		t.Errorf("Want %d records, got %d", len(ids), len(recs))
+	}
+
+	c, _, _, _, _ := ssh.ParseAuthorizedKey(testdata.Cert)
+	cert := c.(*ssh.Certificate)
+	cert.ValidBefore = uint64(time.Now().Add(1 * time.Hour).UTC().Unix())
+	if err := db.SetCert(cert); err != nil {
+		t.Error(err)
+	}
+
+	if _, err := db.Get("key"); err != nil {
+		t.Error(err)
+	}
+	if err := db.Revoke("key"); err != nil {
+		t.Error(err)
+	}
+
+	// A revoked key shouldn't get returned if it's already expired
+	db.Revoke("a")
+
+	revoked, err := db.GetRevoked()
+	if err != nil {
+		t.Error(err)
+	}
+	for _, k := range revoked {
+		if k.KeyID != "key" {
+			t.Errorf("Unexpected key: %s", k.KeyID)
+		}
+	}
+}
+
+func TestMemoryStore(t *testing.T) {
+	db := NewMemoryStore()
+	testStore(t, db)
+}
+
+func TestMySQLStore(t *testing.T) {
+	config := os.Getenv("MYSQL_TEST_CONFIG")
+	if config == "" {
+		t.Skip("No MYSQL_TEST_CONFIG environment variable")
+	}
+	db, err := NewMySQLStore(config)
+	if err != nil {
+		t.Error(err)
+	}
+	testStore(t, db)
+}