S3: stamp the gateway's own uid/gid on PutObject and copy entries (#10844)

* fix(s3): stamp the gateway's own ids on single-shot PutObject entries

putToFiler builds the entry in the gateway now instead of proxying a PUT to
the filer, and it hardcoded Uid/Gid 0 while every sibling write path stamps
filer_pb.OS_UID/OS_GID. On a non-root deployment that leaves single-shot PUTs
and multipart parts owned by root while directories and completed multipart
objects keep the real ids, so a mount reader can list the tree but gets EACCES
on every open once objects are not world-readable.

* fix(s3): stamp mode and ownership on copy destinations

CopyObject and UploadPartCopy build the destination attributes themselves and
then assign them over the entry filer_pb.MkFile just stamped, so the copy
landed with mode 0000 and uid/gid 0 - unreadable on a mount even by the filer's
own user. Build the destination with the same mode PutObject resolves for the
request and the gateway's own ids.

weed/s3api/s3api_object_handlers_copy.go

@@ -329,6 +329,9 @@ func (s3a *S3ApiServer) CopyObjectHandler(w http.ResponseWriter, r *http.Request
 			Mtime:    t.Unix(),
 			Crtime:   entry.Attributes.Crtime,
 			Mime:     resolveDestinationMime(r.Header, entry.Attributes.Mime, replaceMeta),
+			FileMode: s3a.resolveFileMode(r),
+			Uid:      filer_pb.OS_UID,
+			Gid:      filer_pb.OS_GID,
 		},
 		Extended: make(map[string][]byte),
 	}
@@ -1030,6 +1033,9 @@ func (s3a *S3ApiServer) CopyObjectPartHandler(w http.ResponseWriter, r *http.Req
 			Mtime:    t.Unix(),
 			Crtime:   t.Unix(),
 			Mime:     entry.Attributes.Mime,
+			FileMode: s3a.resolveFileMode(r),
+			Uid:      filer_pb.OS_UID,
+			Gid:      filer_pb.OS_GID,
 		},
 		Extended: make(map[string][]byte),
 	}

weed/s3api/s3api_object_handlers_put.go

@@ -694,8 +694,8 @@ func (s3a *S3ApiServer) putToFiler(r *http.Request, filePath string, dataReader
 			Crtime:   now.Unix(),
 			Mtime:    now.Unix(),
 			FileMode: fileMode,
-			Uid:      0,
-			Gid:      0,
+			Uid:      filer_pb.OS_UID,
+			Gid:      filer_pb.OS_GID,
 			Mime:     mimeType,
 			FileSize: uint64(chunkResult.TotalSize),
 			TtlSec:   lifecycleTTLSec,