From: dqu123 <davidqu12345@gmail.com>
Date: Sat, 10 Oct 2020 20:25:07 +0000 (-0400)
Subject: net/http: deep copy Request.TransferEncoding
X-Git-Tag: go1.16beta1~789
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=0f53453b32054b681dac6e8b025c85a785396102;p=gostls13.git

net/http: deep copy Request.TransferEncoding

The existing implementation in Request.Clone() assigns the wrong
pointer to r2.TransferEncoding.

Fixes #41907

Change-Id: I7f220a41b1b46a55d1a1005e47c6dd69478cb025
Reviewed-on: https://go-review.googlesource.com/c/go/+/261258
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Trust: Emmanuel Odeke <emm.odeke@gmail.com>
---

diff --git a/src/net/http/request.go b/src/net/http/request.go
index fe6b60982c..54ec1c5593 100644
--- a/src/net/http/request.go
+++ b/src/net/http/request.go
@@ -382,7 +382,7 @@ func (r *Request) Clone(ctx context.Context) *Request {
 	if s := r.TransferEncoding; s != nil {
 		s2 := make([]string, len(s))
 		copy(s2, s)
-		r2.TransferEncoding = s
+		r2.TransferEncoding = s2
 	}
 	r2.Form = cloneURLValues(r.Form)
 	r2.PostForm = cloneURLValues(r.PostForm)
diff --git a/src/net/http/request_test.go b/src/net/http/request_test.go
index 42c16d00ea..461d66e05d 100644
--- a/src/net/http/request_test.go
+++ b/src/net/http/request_test.go
@@ -828,6 +828,27 @@ func TestWithContextDeepCopiesURL(t *testing.T) {
 	}
 }
 
+// Ensure that Request.Clone creates a deep copy of TransferEncoding.
+// See issue 41907.
+func TestRequestCloneTransferEncoding(t *testing.T) {
+	body := strings.NewReader("body")
+	req, _ := NewRequest("POST", "https://example.org/", body)
+	req.TransferEncoding = []string{
+		"encoding1",
+	}
+
+	clonedReq := req.Clone(context.Background())
+	// modify original after deep copy
+	req.TransferEncoding[0] = "encoding2"
+
+	if req.TransferEncoding[0] != "encoding2" {
+		t.Error("expected req.TransferEncoding to be changed")
+	}
+	if clonedReq.TransferEncoding[0] != "encoding1" {
+		t.Error("expected clonedReq.TransferEncoding to be unchanged")
+	}
+}
+
 func TestNoPanicOnRoundTripWithBasicAuth_h1(t *testing.T) {
 	testNoPanicWithBasicAuth(t, h1Mode)
 }