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Date:   Wed,  3 Nov 2021 17:02:53 +0800
Message-Id: <20211103170206.Bluez.v2.1.I515833d2764b8ec2ac2bb1f87313de80ebb497cd@changeid>
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Subject: [Bluez PATCH v2 1/3] adapter: Use PeripheralLongTermKey to store LTK
From:   Archie Pusaka <apusaka@google.com>
To:     linux-bluetooth <linux-bluetooth@vger.kernel.org>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Marcel Holtmann <marcel@holtmann.org>
Cc:     CrosBT Upstreaming <chromeos-bluetooth-upstreaming@chromium.org>,
        Archie Pusaka <apusaka@chromium.org>,
        Sonny Sasaka <sonnysasaka@chromium.org>
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From: Archie Pusaka <apusaka@chromium.org>

Introducing PeripheralLongTermKey group for storing LTK info to
replace the less inclusive term. Currently we still need to write/read
from both to ensure smooth transition, but later we should deprecate
the old term.

Reviewed-by: Sonny Sasaka <sonnysasaka@chromium.org>
---

Changes in v2:
- Add reason to keep duplicates as comment

 src/adapter.c | 47 ++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 38 insertions(+), 9 deletions(-)

diff --git a/src/adapter.c b/src/adapter.c
index d0d38621b8..114ae84c10 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -3868,7 +3868,14 @@ static struct smp_ltk_info *get_peripheral_ltk_info(GKeyFile *key_file,
 
 	DBG("%s", peer);
 
-	ltk = get_ltk(key_file, peer, bdaddr_type, "SlaveLongTermKey");
+	/* Peripheral* is the proper term, but for now read both entries
+	 * so it won't break when user up/downgrades. Remove the other
+	 * term after a few releases.
+	 */
+	ltk = get_ltk(key_file, peer, bdaddr_type, "PeripheralLongTermKey");
+	if (!ltk)
+		ltk = get_ltk(key_file, peer, bdaddr_type, "SlaveLongTermKey");
+
 	if (ltk)
 		ltk->central = false;
 
@@ -8415,13 +8422,12 @@ static void new_link_key_callback(uint16_t index, uint16_t length,
 	bonding_complete(adapter, &addr->bdaddr, addr->type, 0);
 }
 
-static void store_longtermkey(struct btd_adapter *adapter, const bdaddr_t *peer,
+static void store_ltk_group(struct btd_adapter *adapter, const bdaddr_t *peer,
 				uint8_t bdaddr_type, const unsigned char *key,
-				uint8_t central, uint8_t authenticated,
+				const char *group, uint8_t authenticated,
 				uint8_t enc_size, uint16_t ediv,
 				uint64_t rand)
 {
-	const char *group = central ? "LongTermKey" : "SlaveLongTermKey";
 	char device_addr[18];
 	char filename[PATH_MAX];
 	GKeyFile *key_file;
@@ -8431,11 +8437,6 @@ static void store_longtermkey(struct btd_adapter *adapter, const bdaddr_t *peer,
 	char *str;
 	int i;
 
-	if (central != 0x00 && central != 0x01) {
-		error("Unsupported LTK type %u", central);
-		return;
-	}
-
 	ba2str(peer, device_addr);
 
 	snprintf(filename, PATH_MAX, STORAGEDIR "/%s/%s/info",
@@ -8475,6 +8476,34 @@ static void store_longtermkey(struct btd_adapter *adapter, const bdaddr_t *peer,
 	g_key_file_free(key_file);
 }
 
+static void store_longtermkey(struct btd_adapter *adapter, const bdaddr_t *peer,
+				uint8_t bdaddr_type, const unsigned char *key,
+				uint8_t central, uint8_t authenticated,
+				uint8_t enc_size, uint16_t ediv,
+				uint64_t rand)
+{
+	if (central != 0x00 && central != 0x01) {
+		error("Unsupported LTK type %u", central);
+		return;
+	}
+
+	if (central) {
+		store_ltk_group(adapter, peer, bdaddr_type, key, "LongTermKey",
+				authenticated, enc_size, ediv, rand);
+	} else {
+		/* Peripheral* is the proper term, but for now keep duplicates
+		 * so it won't break when user up/downgrades. Remove the other
+		 * term after a few releases.
+		 */
+		store_ltk_group(adapter, peer, bdaddr_type, key,
+				"PeripheralLongTermKey", authenticated,
+				enc_size, ediv, rand);
+		store_ltk_group(adapter, peer, bdaddr_type, key,
+				"SlaveLongTermKey", authenticated,
+				enc_size, ediv, rand);
+	}
+}
+
 static void new_long_term_key_callback(uint16_t index, uint16_t length,
 					const void *param, void *user_data)
 {
-- 
2.33.1.1089.g2158813163f-goog