Files
seaweedfs/weed/storage/super_block/super_block_read.go.go
chuanying chenandChris Lu d35f4c1c6b Missing data read in super block extra parsing (#8392)
* storage: fail on short super block extra read even without an error

Some backends (e.g. s3_backend) clear io.EOF after a short read, returning
n < len(p) with a nil error. Checking n only when the error is non-nil
lets truncated extra data reach proto.Unmarshal with a zero-filled tail.

* storage: apply the same short-read check to the super block header

A backend that returns n < SuperBlockSize with a nil error previously
slipped through and parsed a partially zero-filled header.

* storage: test super block extra reads

Covers a round trip through ReadSuperBlock, a truncated extra region, a
backend returning io.EOF alongside a full read, and a backend returning
a short read with a nil error.

---------

Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>
2026-10-21 20:07:52 -07:00

56 lines
1.6 KiB
Go

package super_block
import (
"fmt"
"io"
"google.golang.org/protobuf/proto"
"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
"github.com/seaweedfs/seaweedfs/weed/storage/backend"
"github.com/seaweedfs/seaweedfs/weed/storage/needle"
"github.com/seaweedfs/seaweedfs/weed/util"
)
// ReadSuperBlock reads from data file and load it into volume's super block
func ReadSuperBlock(datBackend backend.BackendStorageFile) (superBlock SuperBlock, err error) {
header := make([]byte, SuperBlockSize)
if n, e := datBackend.ReadAt(header, 0); n != SuperBlockSize {
if e == nil {
e = io.ErrUnexpectedEOF
}
err = fmt.Errorf("cannot read volume %s super block: %v", datBackend.Name(), e)
return
}
superBlock.Version = needle.Version(header[0])
if superBlock.ReplicaPlacement, err = NewReplicaPlacementFromByte(header[1]); err != nil {
err = fmt.Errorf("cannot read replica type: %s", err.Error())
return
}
superBlock.Ttl = needle.LoadTTLFromBytes(header[2:4])
superBlock.CompactionRevision = util.BytesToUint16(header[4:6])
superBlock.ExtraSize = util.BytesToUint16(header[6:8])
if superBlock.ExtraSize > 0 {
// read more
extraData := make([]byte, int(superBlock.ExtraSize))
if n, e := datBackend.ReadAt(extraData, SuperBlockSize); n != len(extraData) {
if e == nil {
e = io.ErrUnexpectedEOF
}
err = fmt.Errorf("cannot read volume %s super block extra: %v", datBackend.Name(), e)
return
}
superBlock.Extra = &master_pb.SuperBlockExtra{}
err = proto.Unmarshal(extraData, superBlock.Extra)
if err != nil {
err = fmt.Errorf("cannot unmarshal volume %s super block extra: %v", datBackend.Name(), err)
return
}
}
return
}