From 30596e9f81c65b439a013fab5e467a37ea8cb744 Mon Sep 17 00:00:00 2001
From: Klaus Post <klauspost@gmail.com>
Date: Tue, 12 Nov 2019 17:42:43 +0300
Subject: [PATCH] zstd: Fix frame content size decoding (#180)

Fix frame content size reading on very large blocks.
---
 zstd/decoder_test.go | 2 +-
 zstd/framedec.go     | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/zstd/decoder_test.go b/zstd/decoder_test.go
index 018c0f8492..78f26c17f4 100644
--- a/zstd/decoder_test.go
+++ b/zstd/decoder_test.go
@@ -95,7 +95,7 @@ func TestNewReaderMismatch(t *testing.T) {
 		n, err := io.ReadFull(dec, buf)
 		if err != nil {
 			if err != io.EOF && err != io.ErrUnexpectedEOF {
-				t.Fatal(err)
+				t.Fatal("block", cHash, "err:", err)
 			}
 		}
 		if n > 0 {
diff --git a/zstd/framedec.go b/zstd/framedec.go
index 9ca1886582..9e00437a2e 100644
--- a/zstd/framedec.go
+++ b/zstd/framedec.go
@@ -194,14 +194,14 @@ func (d *frameDec) reset(br byteBuffer) error {
 			// When FCS_Field_Size is 2, the offset of 256 is added.
 			d.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) + 256
 		case 4:
-			d.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) | (uint64(b[2]) << 16) | (uint64(b[3] << 24))
+			d.FrameContentSize = uint64(b[0]) | (uint64(b[1]) << 8) | (uint64(b[2]) << 16) | (uint64(b[3]) << 24)
 		case 8:
 			d1 := uint32(b[0]) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24)
 			d2 := uint32(b[4]) | (uint32(b[5]) << 8) | (uint32(b[6]) << 16) | (uint32(b[7]) << 24)
 			d.FrameContentSize = uint64(d1) | (uint64(d2) << 32)
 		}
 		if debug {
-			println("field size bits:", v, "fcsSize:", fcsSize, "FrameContentSize:", d.FrameContentSize, hex.EncodeToString(b[:fcsSize]))
+			println("field size bits:", v, "fcsSize:", fcsSize, "FrameContentSize:", d.FrameContentSize, hex.EncodeToString(b[:fcsSize]), "singleseg:", d.SingleSegment, "window:", d.WindowSize)
 		}
 	}
 	// Move this to shared.
@@ -414,6 +414,7 @@ func (d *frameDec) startDecoder(output chan decodeOutput) {
 		}
 		written += int64(len(r.b))
 		if d.SingleSegment && uint64(written) > d.FrameContentSize {
+			println("runDecoder: single segment and", uint64(written), ">", d.FrameContentSize)
 			r.err = ErrFrameSizeExceeded
 			output <- r
 			return
@@ -464,6 +465,7 @@ func (d *frameDec) runDecoder(dst []byte, dec *blockDec) ([]byte, error) {
 			break
 		}
 		if d.SingleSegment && uint64(len(d.history.b)) > d.o.maxDecodedSize {
+			println("runDecoder: single segment and", uint64(len(d.history.b)), ">", d.o.maxDecodedSize)
 			err = ErrFrameSizeExceeded
 			break
 		}