[PATCH BlueZ v2] core/adapter: Add support for enabling privacy

["Michał Narajowski" <michal.narajowski@codecoup.pl>]

This adds support for loading local IRK key when adapter is configured.
In case IRK is not present new key is generated and stored.
In case of errors privacy is explicitly disabled. We ensure that we
memset IRK to zero before disabling privacy.
IRK is stored in %s/identity file. Privacy setting is configured
globally in main.conf. In the future we may add per device
configuration in %s/settings.
---
 doc/settings-storage.txt |  12 +++++
 src/adapter.c            | 122 +++++++++++++++++++++++++++++++++++++++++++++++
 src/hcid.h               |   2 +
 src/main.c               |  21 ++++++++
 src/main.conf            |   7 +++
 5 files changed, 164 insertions(+)

diff --git a/doc/settings-storage.txt b/doc/settings-storage.txt
index 2c34ec4..6a708b4 100644
--- a/doc/settings-storage.txt
+++ b/doc/settings-storage.txt
@@ -89,6 +89,18 @@ Sample:
   DiscoverableTimeout=0
 
 
+Identity file format
+====================
+Identity file contains one [General] group that holds identity information
+such as keys and adresses:
+
+	IdentityResolvingKey	String	128-bit value of the IRK
+
+Sample:
+  [General]
+  IdentityResolvingKey=00112233445566778899aabbccddeeff
+
+
 Attributes file format
 ======================
 
diff --git a/src/adapter.c b/src/adapter.c
index b096d48..500df91 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -3141,6 +3141,125 @@ static struct conn_param *get_conn_param(GKeyFile *key_file, const char *peer,
 	return param;
 }
 
+static int generate_and_write_irk(uint8_t *irk, GKeyFile *key_file,
+							const char *filename)
+{
+	struct bt_crypto *crypto;
+	char str_irk_out[33];
+	gsize length = 0;
+	char *str;
+	int i;
+
+	crypto = bt_crypto_new();
+	if (!crypto) {
+		error("Failed to open crypto");
+		return -1;
+	}
+
+	if (!bt_crypto_random_bytes(crypto, irk, 16)) {
+		error("Failed to generate IRK");
+		bt_crypto_unref(crypto);
+		return -1;
+	}
+
+	bt_crypto_unref(crypto);
+
+	for (i = 0; i < 16; i++)
+		sprintf(str_irk_out + (i * 2), "%02x", irk[i]);
+
+	str_irk_out[32] = '\0';
+	info("Generated IRK successfully");
+
+	g_key_file_set_string(key_file, "General", "IdentityResolvingKey",
+								str_irk_out);
+	str = g_key_file_to_data(key_file, &length, NULL);
+	g_file_set_contents(filename, str, length, NULL);
+	g_free(str);
+	DBG("Generated IRK written to file");
+	return 0;
+}
+
+static int load_irk(struct btd_adapter *adapter, uint8_t *irk)
+{
+	char filename[PATH_MAX];
+	GKeyFile *key_file;
+	char address[18];
+	char *str_irk;
+	int ret;
+
+	ba2str(&adapter->bdaddr, address);
+	snprintf(filename, PATH_MAX, STORAGEDIR "/%s/identity", address);
+
+	key_file = g_key_file_new();
+	g_key_file_load_from_file(key_file, filename, 0, NULL);
+
+	str_irk = g_key_file_get_string(key_file, "General",
+						"IdentityResolvingKey", NULL);
+	if (!str_irk) {
+		info("No IRK for %s, creating new IRK", address);
+		ret = generate_and_write_irk(irk, key_file, filename);
+		g_key_file_free(key_file);
+		return ret;
+	}
+
+	g_key_file_free(key_file);
+
+	if (strlen(str_irk) != 32 || str2buf(str_irk, irk, 16)) {
+		/* TODO re-create new IRK here? */
+		error("Invalid IRK format, disabling privacy");
+		g_free(str_irk);
+		return -1;
+	}
+
+	g_free(str_irk);
+	DBG("Successfully read IRK from file");
+	return 0;
+}
+
+static void set_privacy_complete(uint8_t status, uint16_t length,
+					const void *param, void *user_data)
+{
+	struct btd_adapter *adapter = user_data;
+
+	if (status != MGMT_STATUS_SUCCESS) {
+		btd_error(adapter->dev_id, "Failed to set privacy: %s (0x%02x)",
+						mgmt_errstr(status), status);
+		return;
+	}
+
+	DBG("Successfuly set privacy for index %u", adapter->dev_id);
+}
+
+static int set_privacy(struct btd_adapter *adapter, uint8_t privacy)
+{
+	struct mgmt_cp_set_privacy cp;
+
+	memset(&cp, 0, sizeof(cp));
+
+	if (privacy) {
+		uint8_t irk[16];
+
+		if (load_irk(adapter, irk) == 0) {
+			cp.privacy = privacy;
+			memcpy(cp.irk, irk, 16);
+		}
+	}
+
+	DBG("sending set privacy command for index %u", adapter->dev_id);
+	DBG("setting privacy mode 0x%02x for index %u", cp.privacy,
+							adapter->dev_id);
+
+	if (mgmt_send(adapter->mgmt, MGMT_OP_SET_PRIVACY,
+				adapter->dev_id, sizeof(cp), &cp,
+				set_privacy_complete, adapter, NULL) > 0)
+		return 0;
+
+	btd_error(adapter->dev_id, "Failed to set privacy for index %u",
+							adapter->dev_id);
+
+	return -1;
+}
+
 static void load_link_keys_complete(uint8_t status, uint16_t length,
 					const void *param, void *user_data)
 {
@@ -7896,6 +8015,9 @@ static void read_info_complete(uint8_t status, uint16_t length,
 	if (missing_settings & MGMT_SETTING_SECURE_CONN)
 		set_mode(adapter, MGMT_OP_SET_SECURE_CONN, 0x01);
 
+	if (adapter->supported_settings & MGMT_SETTING_PRIVACY)
+		set_privacy(adapter, main_opts.privacy);
+
 	if (main_opts.fast_conn &&
 			(missing_settings & MGMT_SETTING_FAST_CONNECTABLE))
 		set_mode(adapter, MGMT_OP_SET_FAST_CONNECTABLE, 0x01);
diff --git a/src/hcid.h b/src/hcid.h
index 60e2b0a..0b785ee 100644
--- a/src/hcid.h
+++ b/src/hcid.h
@@ -35,6 +35,8 @@ struct main_opts {
 	uint16_t	autoto;
 	uint32_t	pairto;
 	uint32_t	discovto;
+	uint8_t		privacy;
+
 	gboolean	reverse_sdp;
 	gboolean	name_resolv;
 	gboolean	debug_keys;
diff --git a/src/main.c b/src/main.c
index ebc93f5..bcc1e6f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -89,6 +89,7 @@ static const char * const supported_options[] = {
 	"DebugKeys",
 	"ControllerMode",
 	"MultiProfile",
+	"Privacy",
 };
 
 GKeyFile *btd_get_main_conf(void)
@@ -255,6 +256,26 @@ static void parse_config(GKeyFile *config)
 		main_opts.autoto = val;
 	}
 
+	str = g_key_file_get_string(config, "General", "Privacy", &err);
+	if (err) {
+		DBG("%s", err->message);
+		g_clear_error(&err);
+		main_opts.privacy = 0x00;
+	} else {
+		DBG("privacy=%s", str);
+
+		if (!strcmp(str, "device"))
+			main_opts.privacy = 0x01;
+		else if (!strcmp(str, "off"))
+			main_opts.privacy = 0x00;
+		else {
+			DBG("Invalid privacy option: %s", str);
+			main_opts.privacy = 0x00;
+		}
+
+		g_free(str);
+	}
+
 	str = g_key_file_get_string(config, "General", "Name", &err);
 	if (err) {
 		DBG("%s", err->message);
diff --git a/src/main.conf b/src/main.conf
index 49528b9..d9cd9e0 100644
--- a/src/main.conf
+++ b/src/main.conf
@@ -64,6 +64,13 @@
 # 'false'.
 #FastConnectable = false
 
+# Default privacy setting.
+# Enables use of private address.
+# Possible values: "off", "device", "network"
+# "network" option not supported currently
+# Defaults to "off"
+# Privacy = off
+
 #[Policy]
 #
 # The ReconnectUUIDs defines the set of remote services that should try
-- 
2.7.4