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[:]),
+	)
+}