fix(addressbook): validate address entrie to prevent nil dereference

pkg/addressbook/addressbook.go

@@ -82,6 +82,9 @@ func (s *store) Get(overlay swarm.Address) (*bzz.Address, bool, error) {
 		}
 		return nil, false, err
 	}
+	if v.Address == nil {
+		return nil, false, ErrNotFound
+	}
 	return v.Address, v.Verified, nil
 }
 

pkg/addressbook/addressbook_test.go

@@ -5,6 +5,7 @@
 package addressbook_test
 
 import (
+	"encoding/json"
 	"errors"
 	"testing"
 
@@ -13,6 +14,7 @@ import (
 	"github.com/ethersphere/bee/v2/pkg/bzz"
 	"github.com/ethersphere/bee/v2/pkg/crypto"
 	"github.com/ethersphere/bee/v2/pkg/statestore/mock"
+	"github.com/ethersphere/bee/v2/pkg/storage"
 	"github.com/ethersphere/bee/v2/pkg/swarm"
 	ma "github.com/multiformats/go-multiaddr"
 )
@@ -96,3 +98,44 @@ func run(t *testing.T, f bookFunc) {
 		t.Fatalf("expected addresses len %v, got %v", 1, len(addresses))
 	}
 }
+
+type mockCorruptedStore struct{}
+
+func (m *mockCorruptedStore) Get(key string, i any) error {
+	corruptedJSON := []byte(`{"address": null}`)
+	return json.Unmarshal(corruptedJSON, i)
+}
+
+func (m *mockCorruptedStore) Put(key string, i any) error {
+	return nil
+}
+
+func (m *mockCorruptedStore) Delete(key string) error {
+	return nil
+}
+
+func (m *mockCorruptedStore) Iterate(prefix string, fn storage.StateIterFunc) error {
+	return nil
+}
+
+func (m *mockCorruptedStore) Close() error {
+	return nil
+}
+
+func TestGetCorruptedNilAddress(t *testing.T) {
+	t.Parallel()
+
+	corruptedStore := &mockCorruptedStore{}
+	book := addressbook.New(corruptedStore)
+
+	addr := swarm.NewAddress([]byte{0, 1, 2, 3})
+
+	v, _, err := book.Get(addr)
+	if !errors.Is(err, addressbook.ErrNotFound) {
+		t.Fatalf("expected ErrNotFound for corrupted entry, got %v", err)
+	}
+
+	if v != nil {
+		t.Fatalf("expected nil address, got %s", v)
+	}
+}