http2: accept zero-length block fragments in HEADERS frames
Fix a fencepost error which rejects HEADERS frames with neither
payload nor padding, but accepts ones with padding and no payload.
Fixes golang/go#47851.
Change-Id: Ic6ed65571366e86980a5ec69e7f9e6ab958f3b07
Reviewed-on: https://go-review.googlesource.com/c/net/+/344029
Trust: Damien Neil <dneil@google.com>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/http2/frame.go b/http2/frame.go
index 514c126..b95d6f2 100644
--- a/http2/frame.go
+++ b/http2/frame.go
@@ -1018,7 +1018,7 @@
return nil, err
}
}
- if len(p)-int(padLength) <= 0 {
+ if len(p)-int(padLength) < 0 {
return nil, streamError(fh.StreamID, ErrCodeProtocol)
}
hf.headerFragBuf = p[:len(p)-int(padLength)]
diff --git a/http2/frame_test.go b/http2/frame_test.go
index cc0c737..48bf969 100644
--- a/http2/frame_test.go
+++ b/http2/frame_test.go
@@ -312,6 +312,23 @@
headerFragBuf: []byte("abc"),
},
},
+ {
+ "zero length",
+ HeadersFrameParam{
+ StreamID: 42,
+ Priority: PriorityParam{},
+ },
+ "\x00\x00\x00\x01\x00\x00\x00\x00*",
+ &HeadersFrame{
+ FrameHeader: FrameHeader{
+ valid: true,
+ StreamID: 42,
+ Type: FrameHeaders,
+ Length: 0,
+ },
+ Priority: PriorityParam{},
+ },
+ },
}
for _, tt := range tests {
fr, buf := testFramer()
