ssl: add expert info for session resumption

Add expert info to the Change Cipher Spec tree when session resumption
is detected. This can be used as hint that decryption using a RSA key
file will not succeed because of missing key material.

The name of this expert info is "ssl.resumed" or "dtls.resumed" and the
expert info message is "This session reuses previously negotiated keys
(Session resumption)".

Change-Id: I4a83edb13417631c97d6cfc4a57e2086bd217878
Reviewed-on: https://code.wireshark.org/review/11583
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 22 insertions, 2 deletions

diff --git a/epan/dissectors/packet-ssl-utils.h b/epan/dissectors/packet-ssl-utils.h
index 4e3be07eea..f7a2496759 100644
--- a/epan/dissectors/packet-ssl-utils.h
+++ b/epan/dissectors/packet-ssl-utils.h
@@ -236,6 +236,7 @@ typedef struct _StringInfo {
 #define SSL_PRE_MASTER_SECRET   (1<<6)
 #define SSL_CLIENT_EXTENDED_MASTER_SECRET (1<<7)
 #define SSL_SERVER_EXTENDED_MASTER_SECRET (1<<8)
+#define SSL_SERVER_HELLO_DONE   (1<<9)
 
 #define SSL_EXTENDED_MASTER_SECRET_MASK (SSL_CLIENT_EXTENDED_MASTER_SECRET|SSL_SERVER_EXTENDED_MASTER_SECRET)
 
@@ -368,6 +369,7 @@ typedef struct _SslSession {
     /* The Application layer protocol if known (for STARTTLS support) */
     dissector_handle_t   app_handle;
     guint32              last_nontls_frame;
+    gboolean             is_session_resumed;
 } SslSession;
 
 /* RFC 5246, section 8.1 says that the master secret is always 48 bytes */
@@ -613,6 +615,7 @@ ssl_calculate_handshake_hash(SslDecryptSession *ssl_session, tvbuff_t *tvb, guin
 /* common header fields, subtrees and expert info for SSL and DTLS dissectors */
 typedef struct ssl_common_dissect {
     struct {
+        gint change_cipher_spec;
         gint hs_exts_len;
         gint hs_ext_alpn_len;
         gint hs_ext_alpn_list;
@@ -744,6 +747,7 @@ typedef struct ssl_common_dissect {
         expert_field hs_sig_hash_alg_len_bad;
         expert_field hs_cipher_suites_len_bad;
         expert_field hs_sig_hash_algs_bad;
+        expert_field resumed;
 
         /* do not forget to update SSL_COMMON_LIST_T and SSL_COMMON_EI_LIST! */
     } ei;
@@ -765,6 +769,13 @@ typedef struct {
     /* Do not forget to initialize ssl_hfs to -1 in packet-ssl.c! */
 } ssl_hfs_t;
 
+void
+ssl_dissect_change_cipher_spec(ssl_common_dissect_t *hf, tvbuff_t *tvb,
+                               packet_info *pinfo, proto_tree *tree,
+                               guint32 offset, SslSession *session,
+                               gboolean is_from_server,
+                               const SslDecryptSession *ssl);
+
 extern void
 ssl_dissect_hnd_cli_hello(ssl_common_dissect_t *hf, tvbuff_t *tvb,
                           packet_info *pinfo, proto_tree *tree, guint32 offset,
@@ -827,20 +838,25 @@ ssl_common_dissect_t name = {   \
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, \
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, \
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, \
-        -1, -1, -1                                                      \
+        -1, -1, -1, -1,                                                 \
     },                                                                  \
     /* ett */ {                                                         \
         -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, \
         -1, -1, -1, -1,                                                 \
     },                                                                  \
     /* ei */ {                                                          \
-        EI_INIT, EI_INIT, EI_INIT, EI_INIT,                             \
+        EI_INIT, EI_INIT, EI_INIT, EI_INIT, EI_INIT,                    \
     },                                                                  \
 }
 /* }}} */
 
 /* {{{ */
 #define SSL_COMMON_HF_LIST(name, prefix)                                \
+    { & name .hf.change_cipher_spec,                                    \
+      { "Change Cipher Spec Message", prefix ".change_cipher_spec",     \
+        FT_NONE, BASE_NONE, NULL, 0x0,                                  \
+        "Signals a change in cipher specifications", HFILL }            \
+    },                                                                  \
     { & name .hf.hs_exts_len,                                           \
       { "Extensions Length", prefix ".handshake.extensions_length",     \
         FT_UINT16, BASE_DEC, NULL, 0x0,                                 \
@@ -1380,6 +1396,10 @@ ssl_common_dissect_t name = {   \
     { & name .ei.hs_sig_hash_algs_bad, \
         { prefix ".handshake.sig_hash_algs.mult2", PI_MALFORMED, PI_ERROR, \
         "Hash Algorithm length must be a multiple of 2", EXPFILL } \
+    }, \
+    { & name .ei.resumed, \
+        { prefix ".resumed", PI_SEQUENCE, PI_NOTE, \
+        "This session reuses previously negotiated keys (Session resumption)", EXPFILL } \
     }
 /* }}} */