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/* export_sslkeys.c
*
* Export SSL Session Keys dialog
* by Sake Blok <sake@euronet.nl> (20110526)
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <glib.h>
#include <epan/address.h>
#include <epan/dissectors/packet-tls-utils.h>
#include <wiretap/secrets-types.h>
#include "ui/ssl_key_export.h"
int
ssl_session_key_count(void)
{
int count = 0;
ssl_master_key_map_t *mk_map = tls_get_master_key_map(false);
if (!mk_map || !mk_map->used_crandom)
return count;
GHashTableIter iter;
void *key;
g_hash_table_iter_init(&iter, mk_map->used_crandom);
while (g_hash_table_iter_next(&iter, &key, NULL)) {
if (g_hash_table_contains(mk_map->crandom, key)) {
count++;
}
if (g_hash_table_contains(mk_map->tls13_client_early, key)) {
count++;
}
if (g_hash_table_contains(mk_map->tls13_client_handshake, key)) {
count++;
}
if (g_hash_table_contains(mk_map->tls13_server_handshake, key)) {
count++;
}
if (g_hash_table_contains(mk_map->tls13_client_appdata, key)) {
count++;
}
if (g_hash_table_contains(mk_map->tls13_server_appdata, key)) {
count++;
}
}
return count;
}
static void
tls_export_client_randoms_func(void *key, void *value, void *user_data, const char* label)
{
unsigned i;
StringInfo *client_random = (StringInfo *)key;
StringInfo *master_secret = (StringInfo *)value;
GString *keylist = (GString *)user_data;
g_string_append(keylist, label);
for (i = 0; i < client_random->data_len; i++) {
g_string_append_printf(keylist, "%.2x", client_random->data[i]);
}
g_string_append_c(keylist, ' ');
for (i = 0; i < master_secret->data_len; i++) {
g_string_append_printf(keylist, "%.2x", master_secret->data[i]);
}
g_string_append_c(keylist, '\n');
}
char*
ssl_export_sessions(size_t *length)
{
/* Output format is:
* "CLIENT_RANDOM zzzz yyyy\n"
* Where zzzz is the client random (always 64 chars)
* Where yyyy is same as above
* So length will always be 13+1+64+1+96+2 = 177 chars
*
* Wireshark can read CLIENT_RANDOM since v1.8.0.
* Both values are exported in case you use the Session-ID for resuming a
* session in a different capture.
*
* TLS 1.3 derived secrets are similar to the CLIENT_RANDOM master secret
* export, but with a (longer) label indicating the type of derived secret
* to which the client random maps, e.g.
* "CLIENT_HANDSHAKE_TRAFFIC_SECRET zzzz yyyy\n"
*
* The TLS 1.3 values are obtained from an existing key log, but exporting
* them is useful in order to filter actually used secrets or add a DSB.
*/
ssl_master_key_map_t *mk_map = tls_get_master_key_map(false);
if (!mk_map) {
*length = 0;
return g_strdup("");
}
size_t len = 177 * (size_t)ssl_session_key_count();
GString *keylist = g_string_sized_new(len);
GHashTableIter iter;
void *key, *value;
g_hash_table_iter_init(&iter, mk_map->used_crandom);
while (g_hash_table_iter_next(&iter, &key, NULL)) {
if ((value = g_hash_table_lookup(mk_map->crandom, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "CLIENT_RANDOM ");
}
if ((value = g_hash_table_lookup(mk_map->tls13_client_early, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "CLIENT_EARLY_TRAFFIC_SECRET ");
}
if ((value = g_hash_table_lookup(mk_map->tls13_client_handshake, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "CLIENT_HANDSHAKE_TRAFFIC_SECRET ");
}
if ((value = g_hash_table_lookup(mk_map->tls13_server_handshake, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "SERVER_HANDSHAKE_TRAFFIC_SECRET ");
}
if ((value = g_hash_table_lookup(mk_map->tls13_server_appdata, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "SERVER_TRAFFIC_SECRET_0 ");
}
if ((value = g_hash_table_lookup(mk_map->tls13_client_appdata, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "CLIENT_TRAFFIC_SECRET_0 ");
}
#if 0
/* We don't use the EARLY_EXPORT_SECRET or EXPORTER_SECRET now so don't
export, but we may in the future. */
if ((value = g_hash_table_lookup(mk_map->tls13_early_exporter, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "EARLY_EXPORTER_SECRET ");
}
if ((value = g_hash_table_lookup(mk_map->tls13_exporter, key))) {
tls_export_client_randoms_func(key, value, (void *)keylist, "EXPORTER_SECRET ");
}
#endif
}
*length = keylist->len;
return g_string_free(keylist, FALSE);
}
void
tls_export_dsb(capture_file *cf)
{
wtap_block_t block;
wtapng_dsb_mandatory_t *dsb;
size_t secrets_len;
char* secrets = ssl_export_sessions(&secrets_len);
block = wtap_block_create(WTAP_BLOCK_DECRYPTION_SECRETS);
dsb = (wtapng_dsb_mandatory_t *)wtap_block_get_mandatory_data(block);
dsb->secrets_type = SECRETS_TYPE_TLS;
dsb->secrets_data = g_memdup2(secrets, secrets_len);
dsb->secrets_len = (unsigned)secrets_len;
/* XXX - support replacing the DSB of the same type instead of adding? */
wtap_file_add_decryption_secrets(cf->provider.wth, block);
/* Mark the file as having unsaved changes */
cf->unsaved_changes = true;
return;
}
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