// Copyright 2012 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package packet import ( "bytes" "io" "golang.org/x/crypto/openpgp/errors" ) // OpaquePacket represents an OpenPGP packet as raw, unparsed data. This is // useful for splitting and storing the original packet contents separately, // handling unsupported packet types or accessing parts of the packet not yet // implemented by this package. type OpaquePacket struct { // Packet type Tag uint8 // Reason why the packet was parsed opaquely Reason error // Binary contents of the packet data Contents []byte } func (op *OpaquePacket) parse(r io.Reader) (err error) { op.Contents, err = io.ReadAll(r) return } // Serialize marshals the packet to a writer in its original form, including // the packet header. func (op *OpaquePacket) Serialize(w io.Writer) (err error) { err = serializeHeader(w, packetType(op.Tag), len(op.Contents)) if err == nil { _, err = w.Write(op.Contents) } return } // Parse attempts to parse the opaque contents into a structure supported by // this package. If the packet is not known then the result will be another // OpaquePacket. func (op *OpaquePacket) Parse() (p Packet, err error) { hdr := bytes.NewBuffer(nil) err = serializeHeader(hdr, packetType(op.Tag), len(op.Contents)) if err != nil { op.Reason = err return op, err } p, err = Read(io.MultiReader(hdr, bytes.NewBuffer(op.Contents))) if err != nil { op.Reason = err p = op } return } // OpaqueReader reads OpaquePackets from an io.Reader. type OpaqueReader struct { r io.Reader } func NewOpaqueReader(r io.Reader) *OpaqueReader { return &OpaqueReader{r: r} } // Read the next OpaquePacket. func (or *OpaqueReader) Next() (op *OpaquePacket, err error) { tag, _, contents, err := readHeader(or.r) if err != nil { return } op = &OpaquePacket{Tag: uint8(tag), Reason: err} err = op.parse(contents) if err != nil { consumeAll(contents) } return } // OpaqueSubpacket represents an unparsed OpenPGP subpacket, // as found in signature and user attribute packets. type OpaqueSubpacket struct { SubType uint8 Contents []byte } // OpaqueSubpackets extracts opaque, unparsed OpenPGP subpackets from // their byte representation. func OpaqueSubpackets(contents []byte) (result []*OpaqueSubpacket, err error) { var ( subHeaderLen int subPacket *OpaqueSubpacket ) for len(contents) > 0 { subHeaderLen, subPacket, err = nextSubpacket(contents) if err != nil { break } result = append(result, subPacket) contents = contents[subHeaderLen+len(subPacket.Contents):] } return } func nextSubpacket(contents []byte) (subHeaderLen int, subPacket *OpaqueSubpacket, err error) { // RFC 4880, section 5.2.3.1 var subLen uint32 if len(contents) < 1 { goto Truncated } subPacket = &OpaqueSubpacket{} switch { case contents[0] < 192: subHeaderLen = 2 // 1 length byte, 1 subtype byte if len(contents) < subHeaderLen { goto Truncated } subLen = uint32(contents[0]) contents = contents[1:] case contents[0] < 255: subHeaderLen = 3 // 2 length bytes, 1 subtype if len(contents) < subHeaderLen { goto Truncated } subLen = uint32(contents[0]-192)<<8 + uint32(contents[1]) + 192 contents = contents[2:] default: subHeaderLen = 6 // 5 length bytes, 1 subtype if len(contents) < subHeaderLen { goto Truncated } subLen = uint32(contents[1])<<24 | uint32(contents[2])<<16 | uint32(contents[3])<<8 | uint32(contents[4]) contents = contents[5:] } if subLen > uint32(len(contents)) || subLen == 0 { goto Truncated } subPacket.SubType = contents[0] subPacket.Contents = contents[1:subLen] return Truncated: err = errors.StructuralError("subpacket truncated") return } func (osp *OpaqueSubpacket) Serialize(w io.Writer) (err error) { buf := make([]byte, 6) n := serializeSubpacketLength(buf, len(osp.Contents)+1) buf[n] = osp.SubType if _, err = w.Write(buf[:n+1]); err != nil { return } _, err = w.Write(osp.Contents) return }