Expose OpenSSL's key_exchange_info in the content API

net/ssl/ssl_info.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_SSL_SSL_INFO_H_
 #define NET_SSL_SSL_INFO_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ skipping 42 matching lines @@
   // Bitmask of status info of |cert|, representing, for example, known errors
   // and extended validation (EV) status.
   // See cert_status_flags.h for values.
   CertStatus cert_status;
 
   // The security strength, in bits, of the SSL cipher suite.
   // 0 means the connection is not encrypted.
   // -1 means the security strength is unknown.
   int security_bits;
 
+  // Security information of the SSL connection handshake.
+  // The meaning depends on the cipher used, see |SSL_SESSION|'s
+  // key_exchange_info for more information.
+  // A zero indicates that the value is unknown.

[mmenke, 2015/08/26 15:28:37]

Is there a case where for some cipher, an actual value of 0 is possible?

[sigbjorn, 2015/08/26 15:46:15]

No. It will hold either a bit strength (which necessarily is greater than 0), or
an enum value.

In theory OpenSSl's internal representation might grow to hold an enum value of
0 in the future, see https://boringssl-review.googlesource.com/#/c/5280/, search
for "One question for Adam though". It could still avoid reporting it as 0 to
the content layer, even if that was the case.

+  int key_exchange_info;
+
   // Information about the SSL connection itself. See
   // ssl_connection_status_flags.h for values. The protocol version,
   // ciphersuite, and compression in use are encoded within.
   int connection_status;
 
   // If the certificate is valid, then this is true iff it was rooted at a
   // standard CA root. (As opposed to a user-installed root.)
   bool is_issued_by_known_root;
 
   // True if a client certificate was sent to the server.  Note that sending
@@ skipping 15 matching lines @@
   std::string pinning_failure_log;
 
   // List of SignedCertificateTimestamps and their corresponding validation
   // status.
   SignedCertificateTimestampAndStatusList signed_certificate_timestamps;
 };
 
 }  // namespace net
 
 #endif  // NET_SSL_SSL_INFO_H_