openssl: add SSLContext#ecdh_curves=

* ext/openssl/ossl_ssl.c (ossl_sslctx_s_alloc): Enable the automatic
  curve selection for ECDH by calling SSL_CTX_set_ecdh_auto(). With
  this a TLS server automatically selects a curve which both the client
  and the server support to use in ECDH. This changes the default
  behavior but users can still disable ECDH by excluding 'ECDH' cipher
  suites from the cipher list (with SSLContext#ciphers=). This commit
  also deprecate #tmp_ecdh_callback=. It was added in Ruby 2.3.0. It
  wraps SSL_CTX_set_tmp_ecdh_callback() which will be removed in OpenSSL
  1.1.0. Its callback receives two values 'is_export' and 'keylength'
  but both are completely useless for determining a curve to use in
  ECDH. The automatic curve selection was introduced to replace this.

  (ossl_sslctx_setup): Deprecate SSLContext#tmp_ecdh_callback=. Emit a
  warning if this is in use.

  (ossl_sslctx_set_ecdh_curves): Add SSLContext#ecdh_curves=. Wrap
  SSL_CTX_set1_curves_list(). If it is not available, this falls back
  to SSL_CTX_set_tmp_ecdh().

  (Init_ossl_ssl): Define SSLContext#ecdh_curves=.

* ext/openssl/extconf.rb: Check the existence of EC_curve_nist2nid(),
  SSL_CTX_set1_curves_list(), SSL_CTX_set_ecdh_auto() and
  SSL_CTX_set_tmp_ecdh_callback().

* ext/openssl/openssl_missing.[ch]: Implement EC_curve_nist2nid() if
  missing.

* test/openssl/test_pair.rb (test_ecdh_callback): Use
  EnvUtil.suppress_warning to suppress deprecated warning.

  (test_ecdh_curves): Test that SSLContext#ecdh_curves= works.

* test/openssl/utils.rb (start_server): Use SSLContext#ecdh_curves=.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55214 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 59 insertions, 28 deletions

diff --git a/test/openssl/test_pair.rb b/test/openssl/test_pair.rb
index 38b33a4622..d9341ad123 100644
--- a/test/openssl/test_pair.rb
+++ b/test/openssl/test_pair.rb
@@ -372,41 +372,73 @@ module OpenSSL::TestPairM
   end
 
   def test_ecdh_callback
-    called = false
-    ctx2 = OpenSSL::SSL::SSLContext.new
-    ctx2.ciphers = "ECDH"
-    ctx2.tmp_ecdh_callback = ->(*args) {
-      called = true
-      OpenSSL::PKey::EC.new "prime256v1"
-    }
+    return unless OpenSSL::SSL::SSLContext.instance_methods.include?(:tmp_ecdh_callback)
+    EnvUtil.suppress_warning do # tmp_ecdh_callback is deprecated (2016-05)
+      begin
+        called = false
+        ctx2 = OpenSSL::SSL::SSLContext.new
+        ctx2.ciphers = "ECDH"
+        ctx2.tmp_ecdh_callback = ->(*args) {
+          called = true
+          OpenSSL::PKey::EC.new "prime256v1"
+        }
+
+        sock1, sock2 = tcp_pair
+
+        s2 = OpenSSL::SSL::SSLSocket.new(sock2, ctx2)
+        ctx1 = OpenSSL::SSL::SSLContext.new
+        ctx1.ciphers = "ECDH"
+
+        s1 = OpenSSL::SSL::SSLSocket.new(sock1, ctx1)
+        th = Thread.new do
+          begin
+            rv = s1.connect_nonblock(exception: false)
+            case rv
+            when :wait_writable
+              IO.select(nil, [s1], nil, 5)
+            when :wait_readable
+              IO.select([s1], nil, nil, 5)
+            end
+          end until rv == s1
+        end
+
+        accepted = s2.accept
+        assert called, 'ecdh callback should be called'
+      rescue OpenSSL::SSL::SSLError => e
+        if e.message =~ /no cipher match/
+          skip "ECDH cipher not supported."
+        else
+          raise e
+        end
+      ensure
+        th.join if th
+        s1.close if s1
+        s2.close if s2
+        sock1.close if sock1
+        sock2.close if sock2
+      end
+    end
+  end
 
+  def test_ecdh_curves
     sock1, sock2 = tcp_pair
 
-    s2 = OpenSSL::SSL::SSLSocket.new(sock2, ctx2)
     ctx1 = OpenSSL::SSL::SSLContext.new
     ctx1.ciphers = "ECDH"
-
+    ctx1.ecdh_curves = "P-384:P-224"
     s1 = OpenSSL::SSL::SSLSocket.new(sock1, ctx1)
-    th = Thread.new do
-      begin
-        rv = s1.connect_nonblock(exception: false)
-        case rv
-        when :wait_writable
-          IO.select(nil, [s1], nil, 5)
-        when :wait_readable
-          IO.select([s1], nil, nil, 5)
-        end
-      end until rv == s1
-    end
 
-    accepted = s2.accept
+    ctx2 = OpenSSL::SSL::SSLContext.new
+    ctx2.ciphers = "ECDH"
+    ctx2.ecdh_curves = "P-256:P-384"
+    s2 = OpenSSL::SSL::SSLSocket.new(sock2, ctx2)
 
-    assert called, 'ecdh callback should be called'
-  rescue OpenSSL::SSL::SSLError => e
-    if e.message =~ /no cipher match/
-      skip "ECDH cipher not supported."
-    else
-      raise e
+    th = Thread.new { s1.accept }
+    s2.connect
+
+    assert s2.cipher[0].start_with?("AECDH"), "AECDH should be used"
+    if s2.respond_to?(:tmp_key)
+      assert_equal "secp384r1", s2.tmp_key.group.curve_name
     end
   ensure
     th.join if th
@@ -414,7 +446,6 @@ module OpenSSL::TestPairM
     s2.close if s2
     sock1.close if sock1
     sock2.close if sock2
-    accepted.close if accepted.respond_to?(:close)
   end
 
   def test_connect_accept_nonblock_no_exception