net/http: clarify that AddCookie only sanitizes the Cookie being added
AddCookie properly encodes a cookie and appends it to the Cookie header
field but does not modify or sanitize what the Cookie header field
contains already. If a user manualy sets the Cookie header field to
something not conforming to RFC 6265 then a cookie added via AddCookie
might not be retrievable.
Fixes #38437
Change-Id: I232b64ac489b39bb962fe4f7dbdc2ae44fcc0514
Reviewed-on: https://go-review.googlesource.com/c/go/+/235141
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/net/http/request.go b/src/net/http/request.go
index e386f13..e924e2a 100644
--- a/src/net/http/request.go
+++ b/src/net/http/request.go
@@ -425,6 +425,8 @@
// AddCookie does not attach more than one Cookie header field. That
// means all cookies, if any, are written into the same line,
// separated by semicolon.
+// AddCookie only sanitizes c's name and value, and does not sanitize
+// a Cookie header already present in the request.
func (r *Request) AddCookie(c *Cookie) {
s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value))
if c := r.Header.Get("Cookie"); c != "" {
