1 files changed, 14 insertions, 0 deletions

diff --git a/vendor/golang.org/x/net/http2/hpack/hpack.go b/vendor/golang.org/x/net/http2/hpack/hpack.go
index 176644a..85f18a2 100644
--- a/vendor/golang.org/x/net/http2/hpack/hpack.go
+++ b/vendor/golang.org/x/net/http2/hpack/hpack.go
@@ -92,6 +92,8 @@ type Decoder struct {
         // saveBuf is previous data passed to Write which we weren't able
         // to fully parse before. Unlike buf, we own this data.
         saveBuf bytes.Buffer
+
+        firstField bool // processing the first field of the header block
 }
 
 // NewDecoder returns a new decoder with the provided maximum dynamic
@@ -101,6 +103,7 @@ func NewDecoder(maxDynamicTableSize uint32, emitFunc func(f HeaderField)) *Decod
         d := &Decoder{
                 emit:        emitFunc,
                 emitEnabled: true,
+                firstField:  true,
         }
         d.dynTab.table.init()
         d.dynTab.allowedMaxSize = maxDynamicTableSize
@@ -226,11 +229,15 @@ func (d *Decoder) DecodeFull(p []byte) ([]HeaderField, error) {
         return hf, nil
 }
 
+// Close declares that the decoding is complete and resets the Decoder
+// to be reused again for a new header block. If there is any remaining
+// data in the decoder's buffer, Close returns an error.
 func (d *Decoder) Close() error {
         if d.saveBuf.Len() > 0 {
                 d.saveBuf.Reset()
                 return DecodingError{errors.New("truncated headers")}
         }
+        d.firstField = true
         return nil
 }
 
@@ -266,6 +273,7 @@ func (d *Decoder) Write(p []byte) (n int, err error) {
                         d.saveBuf.Write(d.buf)
                         return len(p), nil
                 }
+                d.firstField = false
                 if err != nil {
                         break
                 }
@@ -389,6 +397,12 @@ func (d *Decoder) callEmit(hf HeaderField) error {
 
 // (same invariants and behavior as parseHeaderFieldRepr)
 func (d *Decoder) parseDynamicTableSizeUpdate() error {
+        // RFC 7541, sec 4.2: This dynamic table size update MUST occur at the
+        // beginning of the first header block following the change to the dynamic table size.
+        if !d.firstField && d.dynTab.size > 0 {
+                return DecodingError{errors.New("dynamic table size update MUST occur at the beginning of a header block")}
+        }
+
         buf := d.buf
         size, buf, err := readVarInt(5, buf)
         if err != nil {