From 97b9a8c1e595e2527654e8e4124e4ebc048548a2 Mon Sep 17 00:00:00 2001
From: Filippo Valsorda <filippo@golang.org>
Date: Wed, 19 Jan 2022 11:31:33 +0800
Subject: [PATCH] [release-branch.go1.16] net/http: update bundled
 golang.org/x/net/http2

Pull in security fix

	a5309b3 http2: cap the size of the server's canonical header cache

Updates #50058
Fixes CVE-2021-44716

Change-Id: Ifdd13f97fce168de5fb4b2e74ef2060d059800b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/370575
Trust: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Alex Rakoczy <alex@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

Conflict:NA
Reference:https://github.com/golang/go/commit/d0aebe3e74fe14799f97ddd3f01129697c6a290a
---
 src/net/http/h2_bundle.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 3d83084..06f8808 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -4289,7 +4289,15 @@ func (sc *http2serverConn) canonicalHeader(v string) string {
 		sc.canonHeader = make(map[string]string)
 	}
 	cv = CanonicalHeaderKey(v)
-	sc.canonHeader[v] = cv
+	// maxCachedCanonicalHeaders is an arbitrarily-chosen limit on the number of
+	// entries in the canonHeader cache. This should be larger than the number
+	// of unique, uncommon header keys likely to be sent by the peer, while not
+	// so high as to permit unreaasonable memory usage if the peer sends an unbounded
+	// number of unique header keys.
+	const maxCachedCanonicalHeaders = 32
+	if len(sc.canonHeader) < maxCachedCanonicalHeaders {
+		sc.canonHeader[v] = cv
+	}
 	return cv
 }
 
-- 
2.30.0

