commit 2b23d24c385f5132db82782c851765aa14e396fa
author Sigbjorn Vik <sigbjorn@opera.com> Mon Jun 29 15:07:26 2015 +0200
committer Adam Langley <agl@google.com> Tue Aug 18 22:09:27 2015 +0000
tree ef5f7fa08adf572ae3bab46ed2340cb1e3cb3f7d
parent 894f48c6b3824f2dfa232089426dc821c72ef80e

Make key exchange strength available.

This change stores the size of the group/modulus (for RSA/DHE) or curve
ID (for ECDHE) in the |SSL_SESSION|. This makes it available for UIs
where desired.

Change-Id: I354141da432a08f71704c9683f298b361362483d
Reviewed-on: https://boringssl-review.googlesource.com/5280
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_asn1.c

diff --git a/ssl/ssl_asn1.c b/ssl/ssl_asn1.c
index a2b6879..e516a45 100644
--- a/ssl/ssl_asn1.c
+++ b/ssl/ssl_asn1.c
@@ -116,6 +116,7 @@
  *     ocspResponse            [16] OCTET STRING OPTIONAL,
  *                                   -- stapled OCSP response from the server
  *     extendedMasterSecret    [17] BOOLEAN OPTIONAL,
+ *     keyExchangeInfo         [18] INTEGER OPTIONAL,
  * }
  *
  * Note: historically this serialization has included other optional
@@ -154,6 +155,8 @@
     CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 16;
 static const int kExtendedMasterSecretTag =
     CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 17;
+static const int kKeyExchangeInfoTag =
+    CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC | 18;
 
 static int SSL_SESSION_to_bytes_full(SSL_SESSION *in, uint8_t **out_data,
                                      size_t *out_len, int for_ticket) {
@@ -315,6 +318,13 @@
     }
   }
 
+  if (in->key_exchange_info > 0 &&
+      (!CBB_add_asn1(&session, &child, kKeyExchangeInfoTag) ||
+       !CBB_add_asn1_uint64(&child, in->key_exchange_info))) {
+    OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
+    goto err;
+  }
+
   if (!CBB_finish(&cbb, out_data, out_len)) {
     OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
     goto err;
@@ -413,7 +423,8 @@
   CBS peer, sid_ctx, peer_sha256, original_handshake_hash;
   int has_peer, has_peer_sha256, extended_master_secret;
   uint64_t version, ssl_version;
-  uint64_t session_time, timeout, verify_result, ticket_lifetime_hint;
+  uint64_t session_time, timeout, verify_result, ticket_lifetime_hint,
+      key_exchange_info;
 
   ret = SSL_SESSION_new();
   if (ret == NULL) {
@@ -470,13 +481,22 @@
   }
   if (!CBS_get_optional_asn1_bool(&session, &extended_master_secret,
                                   kExtendedMasterSecretTag,
-                                  0 /* default to false */) ||
-      CBS_len(&session) != 0) {
+                                  0 /* default to false */)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   ret->extended_master_secret = extended_master_secret;
 
+  if (!CBS_get_optional_asn1_uint64(&session, &key_exchange_info,
+                                    kKeyExchangeInfoTag, 0) ||
+      CBS_len(&session) != 0) {
+    OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
+    goto err;
+  }
+  if (key_exchange_info <= 0xffffffff) {
+    ret->key_exchange_info = key_exchange_info;
+  }
+
   if (version != SSL_SESSION_ASN1_VERSION) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_SSL_SESSION);
     goto err;