http2: require either ECDSA or RSA ciphersuite
The HTTP/2 RFC does indeed mandate TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
but in practice, people are also using TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
becuase they are only using an ECDSA certificate. This is the case in acme/autocert.
It doesn't make sense to enforce only RSA in cipher suites if it will
never be used because they are using a ECDSA certificate.
Change-Id: I86dac192a3eb9b74e4268310a3b550b3bd88a37f
Reviewed-on: https://go-review.googlesource.com/30721
Reviewed-by: Tom Bergan <tombergan@google.com>
Run-TryBot: Tom Bergan <tombergan@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/http2/server.go b/http2/server.go
index d790c3b..3e705a0 100644
--- a/http2/server.go
+++ b/http2/server.go
@@ -220,12 +220,15 @@
} else if s.TLSConfig.CipherSuites != nil {
// If they already provided a CipherSuite list, return
// an error if it has a bad order or is missing
- // ECDHE_RSA_WITH_AES_128_GCM_SHA256.
- const requiredCipher = tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
+ // ECDHE_RSA_WITH_AES_128_GCM_SHA256 or ECDHE_ECDSA_WITH_AES_128_GCM_SHA256.
haveRequired := false
sawBad := false
for i, cs := range s.TLSConfig.CipherSuites {
- if cs == requiredCipher {
+ switch cs {
+ case tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+ // Alternative MTI cipher to not discourage ECDSA-only servers.
+ // See http://golang.org/cl/30721 for further information.
+ tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:
haveRequired = true
}
if isBadCipher(cs) {
@@ -235,7 +238,7 @@
}
}
if !haveRequired {
- return fmt.Errorf("http2: TLSConfig.CipherSuites is missing HTTP/2-required TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256")
+ return fmt.Errorf("http2: TLSConfig.CipherSuites is missing an HTTP/2-required AES_128_GCM_SHA256 cipher.")
}
}
diff --git a/http2/server_test.go b/http2/server_test.go
index d06fdea..91db6a2 100644
--- a/http2/server_test.go
+++ b/http2/server_test.go
@@ -3190,11 +3190,17 @@
},
},
{
+ name: "just the alternative required cipher suite",
+ tlsConfig: &tls.Config{
+ CipherSuites: []uint16{tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256},
+ },
+ },
+ {
name: "missing required cipher suite",
tlsConfig: &tls.Config{
CipherSuites: []uint16{tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384},
},
- wantErr: "is missing HTTP/2-required TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256",
+ wantErr: "is missing an HTTP/2-required AES_128_GCM_SHA256 cipher.",
},
{
name: "required after bad",
