1+ Parent: db4efeb8 (http2: deflake TestTransportGroupsPendingDials)
2+ Author: Damien Neil <dneil@google.com>
3+ AuthorDate: 2021-12-06 14:31:43 -0800
4+ Commit: Filippo Valsorda <filippo@golang.org>
5+ CommitDate: 2021-12-09 12:49:13 +0000
6+
7+ http2: cap the size of the server's canonical header cache
8+
9+ The HTTP/2 server keeps a per-connection cache mapping header keys
10+ to their canonicalized form (e.g., "foo-bar" => "Foo-Bar"). Cap the
11+ maximum size of this cache to prevent a peer sending many unique
12+ header keys from causing unbounded memory growth.
13+
14+ Cap chosen arbitrarily at 32 entries. Since this cache does not
15+ include common headers (e.g., "content-type"), 32 seems like more
16+ than enough for almost all normal uses.
17+
18+ Fixes #50058
19+ Fixes CVE-2021-44716
20+
21+ Change-Id: Ia83696dc23253c12af8f26d502557c2cc9841105
22+ Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1290827
23+ Reviewed-by: Roland Shoemaker <bracewell@google.com>
24+ Reviewed-on: https://go-review.googlesource.com/c/net/+/369794
25+ Trust: Filippo Valsorda <filippo@golang.org>
26+ Run-TryBot: Filippo Valsorda <filippo@golang.org>
27+ Trust: Damien Neil <dneil@google.com>
28+ Reviewed-by: Russ Cox <rsc@golang.org>
29+ Reviewed-by: Filippo Valsorda <filippo@golang.org>
30+ TryBot-Result: Gopher Robot <gobot@golang.org>
31+
32+ diff -ru cli-20.10.27-orig/vendor/golang.org/x/net/http2/server.go cli-20.10.27/vendor/golang.org/x/net/http2/server.go
33+ --- cli-20.10.27-orig/vendor/golang.org/x/net/http2/server.go 2024-02-05 08:53:30.802532951 -0800
34+ +++ cli-20.10.27/vendor/golang.org/x/net/http2/server.go 2024-02-05 09:19:08.473430121 -0800
35+ @@ -720,7 +720,15 @@
36+ sc.canonHeader = make(map[string]string)
37+ }
38+ cv = http.CanonicalHeaderKey(v)
39+ - sc.canonHeader[v] = cv
40+ + // maxCachedCanonicalHeaders is an arbitrarily-chosen limit on the number of
41+ + // entries in the canonHeader cache. This should be larger than the number
42+ + // of unique, uncommon header keys likely to be sent by the peer, while not
43+ + // so high as to permit unreaasonable memory usage if the peer sends an unbounded
44+ + // number of unique header keys.
45+ + const maxCachedCanonicalHeaders = 32
46+ + if len(sc.canonHeader) < maxCachedCanonicalHeaders {
47+ + sc.canonHeader[v] = cv
48+ + }
49+ return cv
50+ }
51+
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