diff --git a/tar/asm/disassemble.go b/tar/asm/disassemble.go index 54ef23a..009b3f5 100644 --- a/tar/asm/disassemble.go +++ b/tar/asm/disassemble.go @@ -2,7 +2,6 @@ package asm import ( "io" - "io/ioutil" "github.com/vbatts/tar-split/archive/tar" "github.com/vbatts/tar-split/tar/storage" @@ -119,20 +118,34 @@ func NewInputTarStream(r io.Reader, p storage.Packer, fp storage.FilePutter) (io } } - // it is allowable, and not uncommon that there is further padding on the - // end of an archive, apart from the expected 1024 null bytes. - remainder, err := ioutil.ReadAll(outputRdr) - if err != nil && err != io.EOF { - pW.CloseWithError(err) - return - } - _, err = p.AddEntry(storage.Entry{ - Type: storage.SegmentType, - Payload: remainder, - }) - if err != nil { - pW.CloseWithError(err) - return + // It is allowable, and not uncommon that there is further padding on + // the end of an archive, apart from the expected 1024 null bytes. We + // do this in chunks rather than in one go to avoid cases where a + // maliciously crafted tar file tries to trick us into reading many GBs + // into memory. + const paddingChunkSize = 1024 * 1024 + var paddingChunk [paddingChunkSize]byte + for { + var isEOF bool + n, err := outputRdr.Read(paddingChunk[:]) + if err != nil { + if err != io.EOF { + pW.CloseWithError(err) + return + } + isEOF = true + } + _, err = p.AddEntry(storage.Entry{ + Type: storage.SegmentType, + Payload: paddingChunk[:n], + }) + if err != nil { + pW.CloseWithError(err) + return + } + if isEOF { + break + } } pW.Close() }()