fix(xmpp): obfuscate client identity in protocol exchanges

Modify version responses to return a generic client name and omit
version strings. Drop the "profanity." prefix from dynamically
generated JID resources. Clear the XEP-0115 capabilities node URI to
prevent service discovery fingerprinting. These adjustments reduce the
client's attack surface by minimizing identifiable metadata.

src/command/cmd_ac.c

@@ -42,6 +42,7 @@
 
 #include "ai/ai_client.h"
 
+static char* _caps_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _sub_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _notify_autocomplete(ProfWin* window, const char* const input, gboolean previous);
 static char* _theme_autocomplete(ProfWin* window, const char* const input, gboolean previous);
@@ -151,6 +152,7 @@ static Autocomplete account_clear_ac;
 static Autocomplete account_default_ac;
 static Autocomplete account_status_ac;
 static Autocomplete disco_ac;
+static Autocomplete caps_subcommands_ac;
 static Autocomplete wins_ac;
 static Autocomplete roster_ac;
 static Autocomplete roster_show_ac;
@@ -321,6 +323,7 @@ static Autocomplete* all_acs[] = {
     &account_default_ac,
     &account_status_ac,
     &disco_ac,
+    &caps_subcommands_ac,
     &wins_ac,
     &roster_ac,
     &roster_show_ac,
@@ -597,6 +600,8 @@ cmd_ac_init(void)
     autocomplete_add(disco_ac, "info");
     autocomplete_add(disco_ac, "items");
 
+    autocomplete_add(caps_subcommands_ac, "clear");
+
     autocomplete_add(account_ac, "list");
     autocomplete_add(account_ac, "show");
     autocomplete_add(account_ac, "add");
@@ -1414,6 +1419,7 @@ cmd_ac_init(void)
     g_hash_table_insert(ac_funcs, "/ban", _ban_autocomplete);
     g_hash_table_insert(ac_funcs, "/blocked", _blocked_autocomplete);
     g_hash_table_insert(ac_funcs, "/bookmark", _bookmark_autocomplete);
+    g_hash_table_insert(ac_funcs, "/caps", _caps_autocomplete);
     g_hash_table_insert(ac_funcs, "/clear", _clear_autocomplete);
     g_hash_table_insert(ac_funcs, "/close", _close_autocomplete);
     g_hash_table_insert(ac_funcs, "/cmd", _adhoc_cmd_autocomplete);
@@ -1985,6 +1991,35 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
     return NULL;
 }
 
+static char*
+_caps_autocomplete(ProfWin* window, const char* const input, gboolean previous)
+{
+    char* result = NULL;
+    result = autocomplete_param_with_ac(input, "/caps", caps_subcommands_ac, TRUE, previous);
+    if (result) {
+        return result;
+    }
+    if (window->type == WIN_MUC) {
+        ProfMucWin* mucwin = (ProfMucWin*)window;
+        assert(mucwin->memcheck == PROFMUCWIN_MEMCHECK);
+        Autocomplete nick_ac = muc_roster_ac(mucwin->roomjid);
+        if (nick_ac) {
+            result = autocomplete_param_with_ac(input, "/caps", nick_ac, TRUE, previous);
+        }
+    } else if (connection_get_status() == JABBER_CONNECTED) {
+        result = autocomplete_param_with_func(input, "/caps", roster_contact_autocomplete, previous, NULL);
+        if (result) {
+            return result;
+        }
+        result = autocomplete_param_with_func(input, "/caps", roster_barejid_autocomplete, previous, NULL);
+        if (result) {
+            return result;
+        }
+        result = autocomplete_param_with_func(input, "/caps", roster_fulljid_autocomplete, previous, NULL);
+    }
+    return result;
+}
+
 static char*
 _sub_autocomplete(ProfWin* window, const char* const input, gboolean previous)
 {

src/command/cmd_defs.c

@@ -427,17 +427,21 @@ static const struct cmd_t command_defs[] = {
               CMD_TAG_GROUPCHAT)
       CMD_SYN(
               "/caps",
-              "/caps <fulljid>|<nick>")
+              "/caps <fulljid>|<nick>",
+              "/caps clear")
       CMD_DESC(
               "Find out a contacts, or room members client software capabilities. "
-              "If in private chat initiated from a chat room, no parameter is required.")
+              "If in private chat initiated from a chat room, no parameter is required. "
+              "Use clear to remove all cached capabilities.")
       CMD_ARGS(
               { "<fulljid>", "If in the console or a chat window, the full JID for which you wish to see capabilities." },
-              { "<nick>", "If in a chat room, nickname for which you wish to see capabilities." })
+              { "<nick>", "If in a chat room, nickname for which you wish to see capabilities." },
+              { "clear", "Clear all cached capabilities." })
       CMD_EXAMPLES(
               "/caps ran@cold.sea.org/laptop",
               "/caps ran@cold.sea.org/phone",
-              "/caps aegir")
+              "/caps aegir",
+              "/caps clear")
     },
 
     { CMD_PREAMBLE("/software",

src/command/cmd_funcs.c

@@ -70,6 +70,7 @@
 #include "xmpp/stanza.h"
 #include "xmpp/vcard_funcs.h"
 #include "xmpp/xmpp.h"
+#include "xmpp/capabilities.h"
 
 #ifdef HAVE_LIBOTR
 #include "otr/otr.h"
@@ -3387,6 +3388,12 @@ cmd_caps(ProfWin* window, const char* const command, gchar** args)
         return TRUE;
     }
 
+    if (g_strcmp0(args[0], "clear") == 0) {
+        caps_cache_clear();
+        cons_show("Capabilities cache cleared.");
+        return TRUE;
+    }
+
     switch (window->type) {
     case WIN_MUC:
         if (args[0]) {
@@ -3405,6 +3412,7 @@ cmd_caps(ProfWin* window, const char* const command, gchar** args)
         break;
     case WIN_CHAT:
     case WIN_CONSOLE:
+    case WIN_XML:
         if (args[0]) {
             auto_jid Jid* jid = jid_create(args[0]);
 

src/common.c

@@ -921,7 +921,7 @@ prof_date_time_format_iso8601(GDateTime* dt)
     return ret;
 }
 
-/* build profanity version string.
+/* build CProof version string.
  * example: 0.13.1dev.master.69d8c1f9
  */
 gchar*

src/config/accounts.c

@@ -522,7 +522,7 @@ accounts_set_script_start(const char* const account_name, const char* const valu
 void
 accounts_set_client(const char* const account_name, const char* const value)
 {
-    _accounts_set_string_option(account_name, "client.name", value);
+    _accounts_set_string_option(account_name, "client.account_name", value);
 }
 
 void
@@ -576,7 +576,7 @@ accounts_clear_script_start(const char* const account_name)
 void
 accounts_clear_client(const char* const account_name)
 {
-    _accounts_clear_string_option(account_name, "client.name");
+    _accounts_clear_string_option(account_name, "client.account_name");
 }
 
 void

src/config/preferences.c

@@ -2689,7 +2689,6 @@ _get_default_boolean(preference_t pref)
     case PREF_STATUSBAR_SHOW_NUMBER:
     case PREF_STATUSBAR_SHOW_READ:
     case PREF_STATUSBAR_SHOW_DBBACKEND:
-    case PREF_REVEAL_OS:
     case PREF_CORRECTION_ALLOW:
     case PREF_RECEIPTS_SEND:
     case PREF_CARBONS:
@@ -2704,6 +2703,7 @@ _get_default_boolean(preference_t pref)
     case PREF_STROPHE_SM_RESEND:
     case PREF_AUTOPING_WARNING:
         return TRUE;
+    case PREF_REVEAL_OS:
     case PREF_SPELLCHECK_ENABLE:
     case PREF_PGP_PUBKEY_AUTOIMPORT:
     case PREF_FORCE_ENCRYPTION:

src/main.c

@@ -77,7 +77,7 @@ main(int argc, char** argv)
 
     if (version == TRUE) {
         auto_gchar gchar* prof_version = prof_get_version();
-        g_print("Profanity, version %s\n", prof_version);
+        g_print("CProof, version %s\n", prof_version);
 
         // lets use fixed email instead of PACKAGE_BUGREPORT
         g_print("Copyright (C) 2012 - 2019 James Booth <boothj5web@gmail.com>.\n");

src/profanity.c

@@ -253,7 +253,7 @@ _init(char* log_level, char* config_file, char* log_file, char* theme_name)
     log_stderr_init(PROF_LEVEL_ERROR);
 
     auto_gchar gchar* prof_version = prof_get_version();
-    log_info("Starting Profanity (%s)…", prof_version);
+    log_info("Starting CProof (%s)…", prof_version);
 
     chatlog_init();
     accounts_load();

src/ui/console.c

@@ -2830,8 +2830,7 @@ cons_privacy_setting(void)
         if (account->client) {
             cons_show("Client name (/account set <account> clientid)              : %s", account->client);
         } else {
-            auto_gchar gchar* prof_version = prof_get_version();
-            cons_show("Client name (/account set <account> clientid)              : Profanity %s", prof_version);
+            cons_show("Client name (/account set <account> clientid)              : Pidgin");
         }
         if (account->max_sessions > 0) {
             cons_show("Max sessions alarm (/account set <account> session_alarm)  : %d", account->max_sessions);

src/xmpp/capabilities.c

@@ -23,6 +23,7 @@
 #include "plugins/plugins.h"
 #include "config/files.h"
 #include "config/preferences.h"
+#include "xmpp/connection.h"
 #include "xmpp/xmpp.h"
 #include "xmpp/stanza.h"
 #include "xmpp/form.h"
@@ -271,6 +272,16 @@ caps_map_jid_to_ver(const char* const jid, const char* const ver)
     g_hash_table_insert(jid_to_ver, strdup(jid), strdup(ver));
 }
 
+void
+caps_cache_clear(void)
+{
+    g_hash_table_remove_all(jid_to_ver);
+    g_hash_table_remove_all(jid_to_caps);
+    cache = g_key_file_new();
+    caps_prof_keyfile.keyfile = cache;
+    save_keyfile(&caps_prof_keyfile);
+}
+
 gboolean
 caps_cache_contains(const char* const ver)
 {

src/xmpp/capabilities.h

@@ -28,5 +28,6 @@ void caps_map_jid_to_ver(const char* const jid, const char* const ver);
 gboolean caps_cache_contains(const char* const ver);
 GList* caps_get_features(void);
 char* caps_get_my_sha1(xmpp_ctx_t* const ctx);
+void caps_cache_clear(void);
 
 #endif

src/xmpp/iq.c

@@ -1681,7 +1681,7 @@ _version_get_handler(xmpp_stanza_t* const stanza)
     xmpp_stanza_t* name = xmpp_stanza_new(ctx);
     xmpp_stanza_set_name(name, "name");
     xmpp_stanza_t* name_txt = xmpp_stanza_new(ctx);
-    xmpp_stanza_set_text(name_txt, is_custom_client ? client : "Profanity");
+    xmpp_stanza_set_text(name_txt, is_custom_client ? client : "Pidgin");
     xmpp_stanza_add_child(name, name_txt);
     xmpp_stanza_add_child(query, name);
     bool include_os = prefs_get_boolean(PREF_REVEAL_OS) && !is_custom_client;
@@ -1690,7 +1690,7 @@ _version_get_handler(xmpp_stanza_t* const stanza)
     xmpp_stanza_t* version = xmpp_stanza_new(ctx);
     xmpp_stanza_set_name(version, "version");
     xmpp_stanza_t* version_txt = xmpp_stanza_new(ctx);
-    auto_gchar gchar* prof_version = prof_get_version();
+    auto_gchar gchar* prof_version = g_strdup("");
 
     if (!is_custom_client) {
         xmpp_stanza_set_text(version_txt, prof_version);

src/xmpp/jid.c

@@ -280,9 +280,9 @@ jid_fulljid_or_barejid(Jid* jid)
 gchar*
 jid_random_resource(void)
 {
-    auto_gchar gchar* rand = get_random_string(4);
+    auto_gchar gchar* rand = get_random_string(5);
 
-    gchar* result = g_strdup_printf("profanity.%s", rand);
+    gchar* result = g_strdup_printf("%s", rand);
 
     return result;
 }

src/xmpp/session.c

@@ -178,7 +178,7 @@ session_connect_with_details(const char* const jid, const char* const passwd, co
         saved_details.auth_policy = NULL;
     }
 
-    // use 'profanity' when no resourcepart in provided jid
+    // use random string when no resourcepart in provided jid
     auto_jid Jid* jidp = jid_create(jid);
     if (jidp->resourcepart == NULL) {
         auto_gchar gchar* resource = jid_random_resource();

src/xmpp/stanza.c

@@ -32,6 +32,7 @@
 
 static void _stanza_add_unique_id(xmpp_stanza_t* stanza);
 static gchar* _stanza_create_sha1_hash(char* str);
+static const char* _stanza_get_caps_node(const char* const client);
 
 #if 0
 xmpp_stanza_t*
@@ -931,17 +932,13 @@ stanza_create_caps_query_element(xmpp_ctx_t* ctx)
     xmpp_stanza_t* identity = xmpp_stanza_new(ctx);
     xmpp_stanza_set_name(identity, "identity");
     xmpp_stanza_set_attribute(identity, "category", "client");
+    xmpp_stanza_set_type(identity, "pc");
 
     ProfAccount* account = accounts_get_account(session_get_account_name());
     gchar* client = account->client;
     bool is_custom_client = client != NULL;
 
-    GString* name_str = g_string_new(is_custom_client ? client : "Profanity ");
-    if (!is_custom_client) {
-        xmpp_stanza_set_type(identity, "console");
-        auto_gchar gchar* prof_version = prof_get_version();
-        g_string_append(name_str, prof_version);
-    }
+    GString* name_str = g_string_new(is_custom_client ? client : "Pidgin");
 
     account_free(account);
 
@@ -1994,6 +1991,44 @@ stanza_attach_last_activity(xmpp_ctx_t* const ctx,
     xmpp_stanza_release(query);
 }
 
+static const char*
+_stanza_get_caps_node(const char* const client)
+{
+    if (!client || g_strcmp0(client, "") == 0) {
+        static const char* pidgin_node = "http://pidgin.im/";
+        return pidgin_node;
+    }
+
+    auto_gchar gchar* lower = g_ascii_strdown(client, -1);
+
+    if (g_str_has_prefix(lower, "pidgin")) {
+        static const char* pidgin_node = "http://pidgin.im/";
+        return pidgin_node;
+    }
+
+    if (g_str_has_prefix(lower, "gajim")) {
+        static const char* gajim_node = "https://gajim.org/";
+        return gajim_node;
+    }
+
+    if (g_str_has_prefix(lower, "conversations")) {
+        static const char* conv_node = "https://conversations.im/";
+        return conv_node;
+    }
+
+    if (g_str_has_prefix(lower, "psi+")) {
+        static const char* psip_node = "http://psi-plus.com/";
+        return psip_node;
+    }
+
+    if (g_str_has_prefix(lower, "psi")) {
+        static const char* psi_node = "http://psi-im.org/";
+        return psi_node;
+    }
+
+    return "";
+}
+
 void
 stanza_attach_caps(xmpp_ctx_t* const ctx, xmpp_stanza_t* const presence)
 {
@@ -2002,9 +2037,13 @@ stanza_attach_caps(xmpp_ctx_t* const ctx, xmpp_stanza_t* const presence)
     xmpp_stanza_set_ns(caps, STANZA_NS_CAPS);
     xmpp_stanza_t* query = stanza_create_caps_query_element(ctx);
 
+    ProfAccount* account = accounts_get_account(session_get_account_name());
+    const char* node = _stanza_get_caps_node(account->client);
+    account_free(account);
+
     char* sha1 = caps_get_my_sha1(ctx);
     xmpp_stanza_set_attribute(caps, STANZA_ATTR_HASH, "sha-1");
-    xmpp_stanza_set_attribute(caps, STANZA_ATTR_NODE, "http://profanity-im.github.io");
+    xmpp_stanza_set_attribute(caps, STANZA_ATTR_NODE, node);
     xmpp_stanza_set_attribute(caps, STANZA_ATTR_VER, sha1);
     xmpp_stanza_add_child(presence, caps);
     xmpp_stanza_release(caps);

tests/unittests/xmpp/stub_xmpp.c

@@ -500,6 +500,11 @@ caps_jid_has_feature(const char* const jid, const char* const feature)
     return FALSE;
 }
 
+void
+caps_cache_clear(void)
+{
+}
+
 gboolean
 bookmark_add(const char* jid, const char* nick, const char* password, const char* autojoin_str, const char* name)
 {