From Martin Kaiser via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6463

dissector for HDCP (High bandwidth Digital Content Protection)

HDCP can run on top of TCP, there's no fixed port number assigned. I created a heuristic dissector that's disabled by default and can be enabled by setting a preference (similar to the hilscher dissector). The idea behind this is that some HDCP messages are hard to recognize (e.g. one byte message id + 8 random bytes). Having the dissector enabled at all times may generate false positives.

svn path=/trunk/; revision=39480

1 files changed, 311 insertions, 0 deletions

diff --git a/epan/dissectors/packet-hdcp.c b/epan/dissectors/packet-hdcp.c
new file mode 100644
index 0000000000..74612768b4
--- /dev/null
+++ b/epan/dissectors/packet-hdcp.c
@@ -0,0 +1,311 @@
+/* packet-hdcp.c
+ * Routines for HDCP dissection
+ * Copyright 2011, Martin Kaiser <martin@kaiser.cx>
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/* This dissector is based on the HDCP 2.1 specification.
+   It supports the most common authentication protocol messages. */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/prefs.h>
+#include <epan/ptvcursor.h>
+#include <epan/expert.h>
+
+
+static int proto_hdcp = -1;
+static module_t *hdcp_module;
+static gboolean  hdcp_enable_dissector = FALSE;
+
+void proto_reg_handoff_hdcp(void);
+
+static gint ett_hdcp = -1;
+static gint ett_hdcp_cert = -1;
+
+static int hf_hdcp_msg_id = -1;
+static int hf_hdcp_r_tx = -1;
+static int hf_hdcp_repeater = -1;
+static int hf_hdcp_cert_rcv_id = -1;
+static int hf_hdcp_cert_n = -1;
+static int hf_hdcp_cert_e = -1;
+static int hf_hdcp_cert_rcv_sig = -1;
+static int hf_hdcp_e_kh_km = -1;
+static int hf_hdcp_m = -1;
+static int hf_hdcp_r_rx = -1;
+static int hf_hdcp_h_prime = -1;
+static int hf_hdcp_r_n = -1;
+static int hf_hdcp_l_prime = -1;
+static int hf_hdcp_e_dkey_ks = -1;
+static int hf_hdcp_r_iv = -1;
+
+
+#define ID_AKE_INIT          2
+#define ID_AKE_SEND_CERT     3
+#define ID_AKE_STORED_KM     5
+#define ID_AKE_SEND_RRX      6
+#define ID_AKE_SEND_H_PRIME  7
+#define ID_LC_INIT           9
+#define ID_LC_SEND_L_PRIME  10
+#define ID_SKE_SEND_EKS     11
+#define ID_MAX              31
+
+#define RCV_ID_LEN    5  /* all lengths are in bytes */
+#define N_LEN       128
+#define E_LEN         3
+#define RCV_SIG_LEN 384
+
+#define CERT_RX_LEN   (RCV_ID_LEN + N_LEN + E_LEN + 2 + RCV_SIG_LEN)
+
+
+static const value_string hdcp_msg_id[] = {
+    { ID_AKE_INIT,         "AKE_Init" },
+    { ID_AKE_SEND_CERT,    "AKE_Send_Cert" },
+    { ID_AKE_STORED_KM,    "AKE_Stored_km" },
+    { ID_AKE_SEND_RRX,     "AKE_Send_rrx" },
+    { ID_AKE_SEND_H_PRIME, "AKE_Send_H_prime" },
+    { ID_LC_INIT,          "LC_Init" },
+    { ID_LC_SEND_L_PRIME,  "LC_Send_L_prime" },
+    { ID_SKE_SEND_EKS,     "SKE_Send_Eks" },
+    { 0, NULL }
+};
+
+typedef struct _msg_info_t {
+    guint8  id;
+    guint16 len;  /* number of bytes following initial msg_id field */
+} msg_info_t;
+
+static GHashTable *msg_table = NULL;
+
+static const msg_info_t msg_info[] = {
+    { ID_AKE_INIT,          8 },
+    { ID_AKE_SEND_CERT,    1+CERT_RX_LEN },
+    { ID_AKE_STORED_KM,    32 },
+    { ID_AKE_SEND_RRX,      8 },
+    { ID_AKE_SEND_H_PRIME, 32 },
+    { ID_LC_INIT,           8 },
+    { ID_LC_SEND_L_PRIME,  32 },
+    { ID_SKE_SEND_EKS,     24 }
+ };
+
+static int
+dissect_hdcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+    msg_info_t *mi;
+    proto_item *pi;
+    proto_tree *hdcp_tree = NULL, *cert_tree = NULL;
+    guint8 msg_id;
+    gboolean repeater;
+    guint16 reserved;
+    ptvcursor_t *cursor;
+
+    /* do the plausibility checks before setting up anything */
+    msg_id = tvb_get_guint8(tvb, 0);
+    if (msg_id > ID_MAX)
+        return 0;
+
+    mi = (msg_info_t *)g_hash_table_lookup(msg_table,
+            GUINT_TO_POINTER((guint)msg_id));
+    /* 1 -> start after msg_id byte */
+    if (!mi || mi->len!=tvb_reported_length_remaining(tvb, 1))
+        return 0;
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "HDCP");
+    col_clear(pinfo->cinfo, COL_INFO);
+
+    if (tree) {
+        pi = proto_tree_add_protocol_format(tree, proto_hdcp,
+                tvb, 0, tvb_reported_length(tvb), "HDCP");
+        hdcp_tree = proto_item_add_subtree(pi, ett_hdcp);
+    }
+    cursor = ptvcursor_new(hdcp_tree, tvb, 0);
+
+    col_append_fstr(pinfo->cinfo, COL_INFO, "%s",
+                    val_to_str(msg_id, hdcp_msg_id, "unknown (0x%x)"));
+    ptvcursor_add(cursor, hf_hdcp_msg_id, 1, ENC_BIG_ENDIAN);
+
+    switch (msg_id) {
+        case ID_AKE_INIT:
+            ptvcursor_add(cursor, hf_hdcp_r_tx, 8, ENC_BIG_ENDIAN);
+            break;
+        case ID_AKE_SEND_CERT:
+            repeater = ((tvb_get_guint8(tvb, ptvcursor_current_offset(cursor))
+                        & 0x01) == 0x01);
+            col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "%s",
+                    repeater ? "repeater" : "no repeater");
+            ptvcursor_add(cursor, hf_hdcp_repeater, 1, ENC_BIG_ENDIAN);
+            if (hdcp_tree) {
+                cert_tree = ptvcursor_add_text_with_subtree(cursor, CERT_RX_LEN,
+                        ett_hdcp_cert, "%s", "HDCP Certificate");
+            }
+            ptvcursor_add(cursor, hf_hdcp_cert_rcv_id, RCV_ID_LEN, ENC_NA);
+            ptvcursor_add(cursor, hf_hdcp_cert_n, N_LEN, ENC_NA);
+            ptvcursor_add(cursor, hf_hdcp_cert_e, E_LEN, ENC_BIG_ENDIAN);
+            reserved = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
+            proto_tree_add_text(cert_tree, tvb,
+                        ptvcursor_current_offset(cursor), 2, "reserved bytes");
+            if (reserved != 0) {
+                pi = proto_tree_add_text(cert_tree, tvb,
+                        ptvcursor_current_offset(cursor), 2, "invalid value");
+                expert_add_info_format(pinfo, pi, PI_PROTOCOL, PI_WARN,
+                        "reserved bytes must be set to 0x0");
+            }
+            ptvcursor_advance(cursor, 2);
+            ptvcursor_add(cursor, hf_hdcp_cert_rcv_sig, RCV_SIG_LEN, ENC_NA);
+            if (cert_tree)
+                ptvcursor_pop_subtree(cursor);
+            break;
+        case ID_AKE_STORED_KM:
+            ptvcursor_add(cursor, hf_hdcp_e_kh_km, 16, ENC_NA);
+            ptvcursor_add(cursor, hf_hdcp_m, 16, ENC_NA);
+            break;
+        case ID_AKE_SEND_RRX:
+            ptvcursor_add(cursor, hf_hdcp_r_rx, 8, ENC_BIG_ENDIAN);
+            break;
+        case ID_AKE_SEND_H_PRIME:
+            ptvcursor_add(cursor, hf_hdcp_h_prime, 32, ENC_NA);
+            break;
+        case ID_LC_INIT:
+            ptvcursor_add(cursor, hf_hdcp_r_n, 8, ENC_BIG_ENDIAN);
+            break;
+        case ID_LC_SEND_L_PRIME:
+            ptvcursor_add(cursor, hf_hdcp_l_prime, 32, ENC_NA);
+            break;
+        case ID_SKE_SEND_EKS:
+            ptvcursor_add(cursor, hf_hdcp_e_dkey_ks, 16, ENC_NA);
+            ptvcursor_add(cursor, hf_hdcp_r_iv, 8, ENC_BIG_ENDIAN);
+            break;
+        default:
+            break;
+    }
+
+    ptvcursor_free(cursor);
+    return tvb_reported_length(tvb);
+}
+
+void
+proto_register_hdcp(void)
+{
+    guint i;
+
+    static gint *ett[] = {
+        &ett_hdcp,
+        &ett_hdcp_cert
+    };
+
+    static hf_register_info hf[] = {
+        { &hf_hdcp_msg_id,
+            { "Message ID", "hdcp.msg_id", FT_UINT8, BASE_HEX,
+                VALS(hdcp_msg_id), 0, NULL, HFILL } },
+        { &hf_hdcp_r_tx,
+            { "r_tx", "hdcp.r_tx", FT_UINT64, BASE_HEX,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_repeater,
+            { "Repeater", "hdcp.repeater", FT_BOOLEAN, BASE_NONE,
+                NULL, 0x1, NULL, HFILL } },
+        { &hf_hdcp_cert_rcv_id,
+            { "Receiver ID", "hdcp.cert.rcv_id", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_cert_n,
+            { "Receiver RSA key n", "hdcp.cert.n", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_cert_e,
+            { "Receiver RSA key e", "hdcp.cert.e", FT_UINT24, BASE_HEX,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_cert_rcv_sig,
+            { "Receiver signature", "hdcp.cert.rcv_sig", FT_BYTES,
+                BASE_NONE, NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_e_kh_km,
+            { "E_kh_km", "hdcp.e_kh_km", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_m,
+            { "m", "hdcp.m", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_r_rx,
+            { "r_rx", "hdcp.r_rx", FT_UINT64, BASE_HEX,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_h_prime,
+            { "H'", "hdcp.h_prime", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_r_n,
+            { "r_n", "hdcp.r_n", FT_UINT64, BASE_HEX,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_l_prime,
+            { "L'", "hdcp.l_prime", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_e_dkey_ks,
+            { "E_dkey_ks", "hdcp.e_dkey_ks", FT_BYTES, BASE_NONE,
+                NULL, 0, NULL, HFILL } },
+        { &hf_hdcp_r_iv,
+            { "r_iv", "hdcp.r_iv", FT_UINT64, BASE_HEX,
+                NULL, 0, NULL, HFILL } }
+    };
+
+    msg_table = g_hash_table_new(g_direct_hash, g_direct_equal);
+    for(i=0; i<array_length(msg_info); i++) {
+        g_hash_table_insert(msg_table,
+                GUINT_TO_POINTER((guint)msg_info[i].id),
+                (gpointer)(&msg_info[i]));
+    }
+ 
+    proto_hdcp = proto_register_protocol(
+            "High bandwidth Digital Content Protection", "HDCP", "hdcp");
+
+    hdcp_module = prefs_register_protocol(proto_hdcp, proto_reg_handoff_hdcp);
+    prefs_register_bool_preference(hdcp_module, "enable", "Enable dissector",
+                                   "Enable this dissector (default is false)",
+                                   &hdcp_enable_dissector);
+
+    proto_register_field_array(proto_hdcp, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_hdcp(void)
+{
+    static gboolean prefs_initialized = FALSE;
+
+    if (!prefs_initialized) {
+        heur_dissector_add ("tcp", dissect_hdcp, proto_hdcp);
+
+        prefs_initialized = TRUE;
+    }
+
+    proto_set_decoding(proto_hdcp, hdcp_enable_dissector);
+}
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */