diff options
Diffstat (limited to 'src/archive/zip/reader.go')
| -rw-r--r-- | src/archive/zip/reader.go | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/archive/zip/reader.go b/src/archive/zip/reader.go index 13ff9ddcf42..2d5151af3da 100644 --- a/src/archive/zip/reader.go +++ b/src/archive/zip/reader.go @@ -84,7 +84,15 @@ func (z *Reader) init(r io.ReaderAt, size int64) error { return err } z.r = r - z.File = make([]*File, 0, end.directoryRecords) + // Since the number of directory records is not validated, it is not + // safe to preallocate z.File without first checking that the specified + // number of files is reasonable, since a malformed archive may + // indicate it contains up to 1 << 128 - 1 files. Since each file has a + // header which will be _at least_ 30 bytes we can safely preallocate + // if (data size / 30) >= end.directoryRecords. + if (uint64(size)-end.directorySize)/30 >= end.directoryRecords { + z.File = make([]*File, 0, end.directoryRecords) + } z.Comment = end.comment rs := io.NewSectionReader(r, 0, size) if _, err = rs.Seek(int64(end.directoryOffset), io.SeekStart); err != nil { |