[PATCH 6.1 221/321] Bluetooth: SMP: Fix assumption of Central always being Initiator

27 Aug 2024

6.1-stable review patch.  If anyone has any objections, please let me know.
------------------
From: Luiz Augusto von Dentz luiz.von.dentz@intel.com
[ Upstream commit 28cd47f75185c4818b0fb1b46f2f02faaba96376 ]
SMP initiator role shall be considered the one that initiates the
pairing procedure with SMP_CMD_PAIRING_REQ:
BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 3, Part H
page 1557:
Figure 2.1: LE pairing phases
Note that by sending SMP_CMD_SECURITY_REQ it doesn't change the role to
be Initiator.
Link: https://github.com/bluez/bluez/issues/567
Fixes: b28b4943660f ("Bluetooth: Add strict checks for allowed SMP PDUs")
Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com
Signed-off-by: Sasha Levin sashal@kernel.org
---
 net/bluetooth/smp.c | 144 ++++++++++++++++++++++----------------------
 1 file changed, 72 insertions(+), 72 deletions(-)

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index ecb005bce65ac..d444fa1bd9f97 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -913,7 +913,7 @@ static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth,
     * Confirms and the responder Enters the passkey.
     */
    if (smp->method == OVERLAP) {
-		if (hcon->role == HCI_ROLE_MASTER)
+		if (test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    		smp->method = CFM_PASSKEY;
    	else
    		smp->method = REQ_PASSKEY;
@@ -963,7 +963,7 @@ static u8 smp_confirm(struct smp_chan *smp)
smp_send_cmd(smp->conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
-	if (conn->hcon->out)
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM);
    else
    	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM);
@@ -979,7 +979,8 @@ static u8 smp_random(struct smp_chan *smp)
    int ret;
bt_dev_dbg(conn->hcon->hdev, "conn %p %s", conn,
-		   conn->hcon->out ? "initiator" : "responder");
+		   test_bit(SMP_FLAG_INITIATOR, &smp->flags) ? "initiator" :
+		   "responder");
ret = smp_c1(smp->tk, smp->rrnd, smp->preq, smp->prsp,
    	     hcon->init_addr_type, &hcon->init_addr,
@@ -993,7 +994,7 @@ static u8 smp_random(struct smp_chan *smp)
    	return SMP_CONFIRM_FAILED;
    }
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	u8 stk[16];
    	__le64 rand = 0;
    	__le16 ediv = 0;
@@ -1250,14 +1251,15 @@ static void smp_distribute_keys(struct smp_chan *smp)
    rsp = (void *) &smp->prsp[1];
/* The responder sends its keys first */
-	if (hcon->out && (smp->remote_key_dist & KEY_DIST_MASK)) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags) &&
+	    (smp->remote_key_dist & KEY_DIST_MASK)) {
    	smp_allow_key_dist(smp);
    	return;
    }
req = (void *) &smp->preq[1];
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	keydist = &rsp->init_key_dist;
    	*keydist &= req->init_key_dist;
    } else {
@@ -1426,7 +1428,7 @@ static int sc_mackey_and_ltk(struct smp_chan *smp, u8 mackey[16], u8 ltk[16])
    struct hci_conn *hcon = smp->conn->hcon;
    u8 *na, *nb, a[7], b[7];
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	na   = smp->prnd;
    	nb   = smp->rrnd;
    } else {
@@ -1454,7 +1456,7 @@ static void sc_dhkey_check(struct smp_chan *smp)
    a[6] = hcon->init_addr_type;
    b[6] = hcon->resp_addr_type;
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	local_addr = a;
    	remote_addr = b;
    	memcpy(io_cap, &smp->preq[1], 3);
@@ -1533,7 +1535,7 @@ static u8 sc_passkey_round(struct smp_chan *smp, u8 smp_op)
    	/* The round is only complete when the initiator
    	 * receives pairing random.
    	 */
-		if (!hcon->out) {
+		if (!test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM,
    			     sizeof(smp->prnd), smp->prnd);
    		if (smp->passkey_round == 20)
@@ -1561,7 +1563,7 @@ static u8 sc_passkey_round(struct smp_chan *smp, u8 smp_op)
SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM);
-		if (hcon->out) {
+		if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM,
    			     sizeof(smp->prnd), smp->prnd);
    		return 0;
@@ -1572,7 +1574,7 @@ static u8 sc_passkey_round(struct smp_chan *smp, u8 smp_op)
    case SMP_CMD_PUBLIC_KEY:
    default:
    	/* Initiating device starts the round */
-		if (!hcon->out)
+		if (!test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    		return 0;
bt_dev_dbg(hdev, "Starting passkey round %u",
@@ -1617,7 +1619,7 @@ static int sc_user_reply(struct smp_chan *smp, u16 mgmt_op, __le32 passkey)
    }
/* Initiator sends DHKey check first */
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	sc_dhkey_check(smp);
    	SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);
    } else if (test_and_clear_bit(SMP_FLAG_DHKEY_PENDING, &smp->flags)) {
@@ -1740,7 +1742,7 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
    struct smp_cmd_pairing rsp, *req = (void *) skb->data;
    struct l2cap_chan *chan = conn->smp;
    struct hci_dev *hdev = conn->hcon->hdev;
-	struct smp_chan *smp;
+	struct smp_chan *smp = chan->data;
    u8 key_size, auth, sec_level;
    int ret;
@@ -1749,16 +1751,14 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
    if (skb->len < sizeof(*req))
    	return SMP_INVALID_PARAMS;
-	if (conn->hcon->role != HCI_ROLE_SLAVE)
+	if (smp && test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    	return SMP_CMD_NOTSUPP;
-	if (!chan->data)
+	if (!smp) {
    	smp = smp_chan_create(conn);
-	else
-		smp = chan->data;
-
-	if (!smp)
-		return SMP_UNSPECIFIED;
+		if (!smp)
+			return SMP_UNSPECIFIED;
+	}
/* We didn't start the pairing, so match remote */
    auth = req->auth_req & AUTH_REQ_MASK(hdev);
@@ -1940,7 +1940,7 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
    if (skb->len < sizeof(*rsp))
    	return SMP_INVALID_PARAMS;
-	if (conn->hcon->role != HCI_ROLE_MASTER)
+	if (!test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    	return SMP_CMD_NOTSUPP;
skb_pull(skb, sizeof(*rsp));
@@ -2035,7 +2035,7 @@ static u8 sc_check_confirm(struct smp_chan *smp)
    if (smp->method == REQ_PASSKEY || smp->method == DSP_PASSKEY)
    	return sc_passkey_round(smp, SMP_CMD_PAIRING_CONFIRM);
-	if (conn->hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd),
    		     smp->prnd);
    	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM);
@@ -2057,7 +2057,7 @@ static int fixup_sc_false_positive(struct smp_chan *smp)
    u8 auth;
/* The issue is only observed when we're in responder role */
-	if (hcon->out)
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    	return SMP_UNSPECIFIED;
if (hci_dev_test_flag(hdev, HCI_SC_ONLY)) {
@@ -2093,7 +2093,8 @@ static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb)
    struct hci_dev *hdev = hcon->hdev;
bt_dev_dbg(hdev, "conn %p %s", conn,
-		   hcon->out ? "initiator" : "responder");
+		   test_bit(SMP_FLAG_INITIATOR, &smp->flags) ? "initiator" :
+		   "responder");
if (skb->len < sizeof(smp->pcnf))
    	return SMP_INVALID_PARAMS;
@@ -2115,7 +2116,7 @@ static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb)
    		return ret;
    }
-	if (conn->hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(smp->prnd),
    		     smp->prnd);
    	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RANDOM);
@@ -2150,7 +2151,7 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
    if (!test_bit(SMP_FLAG_SC, &smp->flags))
    	return smp_random(smp);
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	pkax = smp->local_pk;
    	pkbx = smp->remote_pk;
    	na   = smp->prnd;
@@ -2163,7 +2164,7 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
    }
if (smp->method == REQ_OOB) {
-		if (!hcon->out)
+		if (!test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM,
    			     sizeof(smp->prnd), smp->prnd);
    	SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);
@@ -2174,7 +2175,7 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
    if (smp->method == REQ_PASSKEY || smp->method == DSP_PASSKEY)
    	return sc_passkey_round(smp, SMP_CMD_PAIRING_RANDOM);
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	u8 cfm[16];
err = smp_f4(smp->tfm_cmac, smp->remote_pk, smp->local_pk,
@@ -2215,7 +2216,7 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
    	return SMP_UNSPECIFIED;
if (smp->method == REQ_OOB) {
-		if (hcon->out) {
+		if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    		sc_dhkey_check(smp);
    		SMP_ALLOW_CMD(smp, SMP_CMD_DHKEY_CHECK);
    	}
@@ -2289,10 +2290,27 @@ bool smp_sufficient_security(struct hci_conn *hcon, u8 sec_level,
    return false;
 }
+static void smp_send_pairing_req(struct smp_chan *smp, __u8 auth)
+{
+	struct smp_cmd_pairing cp;
+
+	if (smp->conn->hcon->type == ACL_LINK)
+		build_bredr_pairing_cmd(smp, &cp, NULL);
+	else
+		build_pairing_cmd(smp->conn, &cp, NULL, auth);
+
+	smp->preq[0] = SMP_CMD_PAIRING_REQ;
+	memcpy(&smp->preq[1], &cp, sizeof(cp));
+
+	smp_send_cmd(smp->conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
+	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP);
+
+	set_bit(SMP_FLAG_INITIATOR, &smp->flags);
+}
+
 static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
    struct smp_cmd_security_req *rp = (void *) skb->data;
-	struct smp_cmd_pairing cp;
    struct hci_conn *hcon = conn->hcon;
    struct hci_dev *hdev = hcon->hdev;
    struct smp_chan *smp;
@@ -2341,16 +2359,20 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
skb_pull(skb, sizeof(*rp));
-	memset(&cp, 0, sizeof(cp));
-	build_pairing_cmd(conn, &cp, NULL, auth);
+	smp_send_pairing_req(smp, auth);
-	smp->preq[0] = SMP_CMD_PAIRING_REQ;
-	memcpy(&smp->preq[1], &cp, sizeof(cp));
+	return 0;
+}
-	smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
-	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP);
+static void smp_send_security_req(struct smp_chan *smp, __u8 auth)
+{
+	struct smp_cmd_security_req cp;
-	return 0;
+	cp.auth_req = auth;
+	smp_send_cmd(smp->conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp);
+	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_REQ);
+
+	clear_bit(SMP_FLAG_INITIATOR, &smp->flags);
 }
int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
@@ -2421,23 +2443,11 @@ int smp_conn_security(struct hci_conn *hcon, __u8 sec_level)
    		authreq |= SMP_AUTH_MITM;
    }
-	if (hcon->role == HCI_ROLE_MASTER) {
-		struct smp_cmd_pairing cp;
-
-		build_pairing_cmd(conn, &cp, NULL, authreq);
-		smp->preq[0] = SMP_CMD_PAIRING_REQ;
-		memcpy(&smp->preq[1], &cp, sizeof(cp));
-
-		smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
-		SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP);
-	} else {
-		struct smp_cmd_security_req cp;
-		cp.auth_req = authreq;
-		smp_send_cmd(conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp);
-		SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_REQ);
-	}
+	if (hcon->role == HCI_ROLE_MASTER)
+		smp_send_pairing_req(smp, authreq);
+	else
+		smp_send_security_req(smp, authreq);
-	set_bit(SMP_FLAG_INITIATOR, &smp->flags);
    ret = 0;
unlock:
@@ -2688,8 +2698,6 @@ static int smp_cmd_sign_info(struct l2cap_conn *conn, struct sk_buff *skb)
static u8 sc_select_method(struct smp_chan *smp)
 {
-	struct l2cap_conn *conn = smp->conn;
-	struct hci_conn *hcon = conn->hcon;
    struct smp_cmd_pairing *local, *remote;
    u8 local_mitm, remote_mitm, local_io, remote_io, method;
@@ -2702,7 +2710,7 @@ static u8 sc_select_method(struct smp_chan *smp)
     * the "struct smp_cmd_pairing" from them we need to skip the
     * first byte which contains the opcode.
     */
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	local = (void *) &smp->preq[1];
    	remote = (void *) &smp->prsp[1];
    } else {
@@ -2771,7 +2779,7 @@ static int smp_cmd_public_key(struct l2cap_conn *conn, struct sk_buff *skb)
    /* Non-initiating device sends its public key after receiving
     * the key from the initiating device.
     */
-	if (!hcon->out) {
+	if (!test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	err = sc_send_public_key(smp);
    	if (err)
    		return err;
@@ -2833,7 +2841,7 @@ static int smp_cmd_public_key(struct l2cap_conn *conn, struct sk_buff *skb)
    }
if (smp->method == REQ_OOB) {
-		if (hcon->out)
+		if (test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM,
    			     sizeof(smp->prnd), smp->prnd);
@@ -2842,7 +2850,7 @@ static int smp_cmd_public_key(struct l2cap_conn *conn, struct sk_buff *skb)
    	return 0;
    }
-	if (hcon->out)
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_CONFIRM);
if (smp->method == REQ_PASSKEY) {
@@ -2857,7 +2865,7 @@ static int smp_cmd_public_key(struct l2cap_conn *conn, struct sk_buff *skb)
    /* The Initiating device waits for the non-initiating device to
     * send the confirm value.
     */
-	if (conn->hcon->out)
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags))
    	return 0;
err = smp_f4(smp->tfm_cmac, smp->local_pk, smp->remote_pk, smp->prnd,
@@ -2891,7 +2899,7 @@ static int smp_cmd_dhkey_check(struct l2cap_conn *conn, struct sk_buff *skb)
    a[6] = hcon->init_addr_type;
    b[6] = hcon->resp_addr_type;
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	local_addr = a;
    	remote_addr = b;
    	memcpy(io_cap, &smp->prsp[1], 3);
@@ -2916,7 +2924,7 @@ static int smp_cmd_dhkey_check(struct l2cap_conn *conn, struct sk_buff *skb)
    if (crypto_memneq(check->e, e, 16))
    	return SMP_DHKEY_CHECK_FAILED;
-	if (!hcon->out) {
+	if (!test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	if (test_bit(SMP_FLAG_WAIT_USER, &smp->flags)) {
    		set_bit(SMP_FLAG_DHKEY_PENDING, &smp->flags);
    		return 0;
@@ -2928,7 +2936,7 @@ static int smp_cmd_dhkey_check(struct l2cap_conn *conn, struct sk_buff *skb)
sc_add_ltk(smp);
-	if (hcon->out) {
+	if (test_bit(SMP_FLAG_INITIATOR, &smp->flags)) {
    	hci_le_start_enc(hcon, 0, 0, smp->tk, smp->enc_key_size);
    	hcon->enc_key_size = smp->enc_key_size;
    }
@@ -3077,7 +3085,6 @@ static void bredr_pairing(struct l2cap_chan *chan)
    struct l2cap_conn *conn = chan->conn;
    struct hci_conn *hcon = conn->hcon;
    struct hci_dev *hdev = hcon->hdev;
-	struct smp_cmd_pairing req;
    struct smp_chan *smp;
bt_dev_dbg(hdev, "chan %p", chan);
@@ -3129,14 +3136,7 @@ static void bredr_pairing(struct l2cap_chan *chan)
bt_dev_dbg(hdev, "starting SMP over BR/EDR");
-	/* Prepare and send the BR/EDR SMP Pairing Request */
-	build_bredr_pairing_cmd(smp, &req, NULL);
-
-	smp->preq[0] = SMP_CMD_PAIRING_REQ;
-	memcpy(&smp->preq[1], &req, sizeof(req));
-
-	smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(req), &req);
-	SMP_ALLOW_CMD(smp, SMP_CMD_PAIRING_RSP);
+	smp_send_pairing_req(smp, 0x00);
 }
static void smp_resume_cb(struct l2cap_chan *chan)
-- 
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[PATCH 6.1 221/321] Bluetooth: SMP: Fix assumption of Central always being Initiator