Embed the userservice and add serve/agent subcommands for one-binary operation

coordinator/internal/userservice/auth/jwt.go

@@ -0,0 +1,72 @@
+package auth
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+
+	"github.com/emil28092005/SciMesh/coordinator/internal/userservice/domain"
+)
+
+// Claims is the payload of a signed token. Subject (from RegisteredClaims) is
+// the user id — it becomes the coordinator's jobs.owner_id; Role drives
+// authorization; Verified tells the coordinator whether this user's workers are
+// trusted (results accepted without quorum). Both services verify this token
+// locally with the shared HS256 secret, so no runtime call back to the
+// userservice is ever needed.
+type Claims struct {
+	Role     domain.Role `json:"role"`
+	Verified bool        `json:"verified"`
+	jwt.RegisteredClaims
+}
+
+// Issuer signs and verifies tokens with a shared HS256 secret.
+type Issuer struct {
+	secret []byte
+	ttl    time.Duration
+	now    func() time.Time
+}
+
+// NewIssuer builds an Issuer. now defaults to time.Now when nil; tests inject a
+// fixed clock to make expiry deterministic.
+func NewIssuer(secret string, ttl time.Duration, now func() time.Time) Issuer {
+	if now == nil {
+		now = time.Now
+	}
+	return Issuer{secret: []byte(secret), ttl: ttl, now: now}
+}
+
+// Issue returns a signed token for the user, valid for the configured TTL. It
+// takes the whole user so every trust-bearing field (role, verified) travels in
+// the token, keeping the two services from needing a runtime lookup.
+func (i Issuer) Issue(u *domain.User) (string, error) {
+	now := i.now()
+	claims := Claims{
+		Role:     u.Role,
+		Verified: u.Verified,
+		RegisteredClaims: jwt.RegisteredClaims{
+			Subject:   u.ID.String(),
+			IssuedAt:  jwt.NewNumericDate(now),
+			ExpiresAt: jwt.NewNumericDate(now.Add(i.ttl)),
+		},
+	}
+	return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString(i.secret)
+}
+
+// Verify checks the signature and expiry and returns the claims. It pins the
+// algorithm to HMAC, rejecting a token that asks for "none" or an RS256 public
+// key — the classic algorithm-substitution attack against naive verifiers.
+func (i Issuer) Verify(token string) (*Claims, error) {
+	var claims Claims
+	_, err := jwt.ParseWithClaims(token, &claims, func(t *jwt.Token) (any, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
+		}
+		return i.secret, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &claims, nil
+}

coordinator/internal/userservice/auth/jwt_test.go

@@ -0,0 +1,77 @@
+package auth
+
+import (
+	"testing"
+	"time"
+
+	"github.com/golang-jwt/jwt/v5"
+	"github.com/google/uuid"
+
+	"github.com/emil28092005/SciMesh/coordinator/internal/userservice/domain"
+)
+
+const testSecret = "test-secret-at-least-32-bytes-long!!"
+
+func TestIssueVerifyRoundTrip(t *testing.T) {
+	iss := NewIssuer(testSecret, time.Hour, nil)
+	id := uuid.New()
+
+	token, err := iss.Issue(&domain.User{ID: id, Role: domain.RoleAdmin, Verified: true})
+	if err != nil {
+		t.Fatalf("issue: %v", err)
+	}
+
+	claims, err := iss.Verify(token)
+	if err != nil {
+		t.Fatalf("verify: %v", err)
+	}
+	if claims.Subject != id.String() {
+		t.Errorf("sub = %q, want %q", claims.Subject, id.String())
+	}
+	if claims.Role != domain.RoleAdmin {
+		t.Errorf("role = %q, want admin", claims.Role)
+	}
+	if !claims.Verified {
+		t.Error("verified claim not carried in token")
+	}
+}
+
+func TestVerifyRejectsExpired(t *testing.T) {
+	// Negative TTL: the token is already expired when issued.
+	iss := NewIssuer(testSecret, -time.Minute, nil)
+	token, _ := iss.Issue(&domain.User{ID: uuid.New(), Role: domain.RoleUser})
+
+	if _, err := iss.Verify(token); err == nil {
+		t.Error("expired token accepted")
+	}
+}
+
+func TestVerifyRejectsWrongSecret(t *testing.T) {
+	token, _ := NewIssuer(testSecret, time.Hour, nil).Issue(&domain.User{ID: uuid.New(), Role: domain.RoleUser})
+
+	other := NewIssuer("another-secret-also-32-bytes-long!!!", time.Hour, nil)
+	if _, err := other.Verify(token); err == nil {
+		t.Error("token verified under the wrong secret")
+	}
+}
+
+func TestVerifyRejectsNoneAlgorithm(t *testing.T) {
+	// Forge a token signed with "none" — the classic algorithm-substitution
+	// attack. A verifier that trusts the header's alg would accept it.
+	tok := jwt.NewWithClaims(jwt.SigningMethodNone, Claims{
+		Role: domain.RoleAdmin,
+		RegisteredClaims: jwt.RegisteredClaims{
+			Subject:   uuid.New().String(),
+			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Hour)),
+		},
+	})
+	raw, err := tok.SignedString(jwt.UnsafeAllowNoneSignatureType)
+	if err != nil {
+		t.Fatalf("sign none: %v", err)
+	}
+
+	iss := NewIssuer(testSecret, time.Hour, nil)
+	if _, err := iss.Verify(raw); err == nil {
+		t.Error("none-signed token accepted")
+	}
+}

coordinator/internal/userservice/auth/password.go

@@ -0,0 +1,40 @@
+// Package auth holds the cryptographic adapters — password hashing and JWT
+// signing/verification. They implement use-case ports and keep bcrypt and the
+// JWT library out of the domain and use-case layers.
+package auth
+
+import "golang.org/x/crypto/bcrypt"
+
+// Hasher turns plaintext passwords into storable hashes and checks them back.
+type Hasher struct {
+	cost int
+}
+
+// NewHasher builds a Hasher. A cost of 0 uses bcrypt's default work factor.
+func NewHasher(cost int) Hasher {
+	if cost == 0 {
+		cost = bcrypt.DefaultCost
+	}
+	return Hasher{cost: cost}
+}
+
+// Hash returns the bcrypt hash of password. The salt and the cost are embedded
+// in the returned string, so nothing else needs to be stored alongside it.
+//
+// bcrypt silently ignores input past 72 bytes; the use case rejects longer
+// passwords before reaching here so a truncated tail never becomes a security
+// surprise.
+func (h Hasher) Hash(password string) (string, error) {
+	b, err := bcrypt.GenerateFromPassword([]byte(password), h.cost)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+// Compare reports whether password matches the stored hash. It returns a
+// non-nil error (bcrypt.ErrMismatchedHashAndPassword) on any mismatch, which
+// the caller collapses into a generic authentication failure.
+func (h Hasher) Compare(hash, password string) error {
+	return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
+}

coordinator/internal/userservice/auth/password_test.go

@@ -0,0 +1,30 @@
+package auth
+
+import "testing"
+
+func TestHashAndCompare(t *testing.T) {
+	h := NewHasher(0) // default cost
+
+	hash, err := h.Hash("correct horse battery staple")
+	if err != nil {
+		t.Fatalf("hash: %v", err)
+	}
+	if hash == "correct horse battery staple" {
+		t.Fatal("hash must not equal the plaintext")
+	}
+	if err := h.Compare(hash, "correct horse battery staple"); err != nil {
+		t.Errorf("correct password rejected: %v", err)
+	}
+	if err := h.Compare(hash, "wrong password"); err == nil {
+		t.Error("wrong password accepted")
+	}
+}
+
+func TestHashSaltsEachTime(t *testing.T) {
+	h := NewHasher(0)
+	a, _ := h.Hash("same")
+	b, _ := h.Hash("same")
+	if a == b {
+		t.Error("two hashes of the same password must differ (random salt)")
+	}
+}