Function parseNotes

internal/elfexec/elfexec.go:39–115

parseNotes returns the notes from a SHT_NOTE section or PT_NOTE segment.

(reader io.Reader, alignment int, order binary.ByteOrder)

// parseNotes returns the notes from a SHT_NOTE section or PT_NOTE segment.
func parseNotes(reader io.Reader, alignment int, order binary.ByteOrder) ([]elfNote, error) {
	r := bufio.NewReader(reader)

	// padding returns the number of bytes required to pad the given size to an
	// alignment boundary.
	padding := func(size int) int {
		return ((size + (alignment - 1)) &^ (alignment - 1)) - size
	}

	var notes []elfNote
	for {
		noteHeader := make([]byte, 12) // 3 4-byte words
		if _, err := io.ReadFull(r, noteHeader); err == io.EOF {
			break
		} else if err != nil {
			return nil, err
		}
		namesz := order.Uint32(noteHeader[0:4])
		descsz := order.Uint32(noteHeader[4:8])
		typ := order.Uint32(noteHeader[8:12])

		if uint64(namesz) > uint64(maxNoteSize) {
			return nil, fmt.Errorf("note name too long (%d bytes)", namesz)
		}
		var name string
		if namesz > 0 {
			// Documentation differs as to whether namesz is meant to include the
			// trailing zero, but everyone agrees that name is null-terminated.
			// So we'll just determine the actual length after the fact.
			var err error
			name, err = r.ReadString('\x00')
			if err == io.EOF {
				return nil, fmt.Errorf("missing note name (want %d bytes)", namesz)
			} else if err != nil {
				return nil, err
			}
			namesz = uint32(len(name))
			name = name[:len(name)-1]
		}

		// Drop padding bytes until the desc field.
		for n := padding(len(noteHeader) + int(namesz)); n > 0; n-- {
			if _, err := r.ReadByte(); err == io.EOF {
				return nil, fmt.Errorf(
					"missing %d bytes of padding after note name", n)
			} else if err != nil {
				return nil, err
			}
		}

		if uint64(descsz) > uint64(maxNoteSize) {
			return nil, fmt.Errorf("note desc too long (%d bytes)", descsz)
		}
		desc := make([]byte, int(descsz))
		if _, err := io.ReadFull(r, desc); err == io.EOF {
			return nil, fmt.Errorf("missing desc (want %d bytes)", len(desc))
		} else if err != nil {
			return nil, err