security: hardening по результатам аудита безопасности

pkg/domain/backup/backup.go

@@ -3,6 +3,7 @@ package backup
 import (
 	"context"
 	"crypto/rand"
+	"encoding/hex"
 	"fmt"
 	"time"
 
@@ -52,7 +53,6 @@ func RunOnce(ctx context.Context, cfg *config.Config) error {
 	)
 
 	now := time.Now()
-	timestamp := now.UTC().Format("20060102-150405")
 	pgDumpOpts := domainpgdump.Options{
 		Host:          cfg.PG.Host,
 		Port:          cfg.PG.Port,
@@ -60,7 +60,7 @@ func RunOnce(ctx context.Context, cfg *config.Config) error {
 		User:          cfg.PG.User,
 		Password:      cfg.PG.Password,
 		ExcludeTables: cfg.PG.ExcludeTables,
-		Key:           fmt.Sprintf("synapse-%s.dump.pqenc", timestamp),
+		Key:           ArtifactKey(now),
 	}
 
 	if err := runner.Run(ctx, pgDumpOpts, recipients, sink, rand.Reader); err != nil {
@@ -73,3 +73,22 @@ func RunOnce(ctx context.Context, cfg *config.Config) error {
 
 	return nil
 }
+
+// ArtifactKey returns a backup file name that includes a UTC timestamp plus a
+// short random suffix so that two backups started in the same second do not
+// collide.
+func ArtifactKey(timestamp time.Time) string {
+	var randomBytes [3]byte
+	if _, err := rand.Read(randomBytes[:]); err != nil {
+		return fmt.Sprintf(
+			"synapse-%s-%09d.dump.pqenc",
+			timestamp.UTC().Format("20060102-150405"),
+			timestamp.Nanosecond(),
+		)
+	}
+	return fmt.Sprintf(
+		"synapse-%s-%s.dump.pqenc",
+		timestamp.UTC().Format("20060102-150405"),
+		hex.EncodeToString(randomBytes[:]),
+	)
+}

pkg/domain/backup/backup_test.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"strings"
 	"testing"
+	"time"
 
 	"git.tswf.io/infra/go-synapse-backupper/pkg/adapters/config"
 	"git.tswf.io/infra/go-synapse-backupper/pkg/adapters/crypto/keymanager"
@@ -127,3 +128,21 @@ func TestRunOnce_ValidKeys_PgDumpMissing(t *testing.T) {
 		}
 	}
 }
+
+func TestArtifactKey(t *testing.T) {
+	ts := time.Date(2025, 1, 2, 15, 4, 5, 0, time.UTC)
+	key := ArtifactKey(ts)
+
+	wantPrefix := "synapse-20250102-150405-"
+	if !strings.HasPrefix(key, wantPrefix) {
+		t.Errorf("key = %q, want prefix %q", key, wantPrefix)
+	}
+	if !strings.HasSuffix(key, ".dump.pqenc") {
+		t.Errorf("key = %q, want suffix .dump.pqenc", key)
+	}
+
+	secondKey := ArtifactKey(ts)
+	if key == secondKey {
+		t.Errorf("two keys for the same timestamp collide: %q", key)
+	}
+}