[v3] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()

Commit Message

Sungwoo Kim May 4, 2024, 6:28 p.m. UTC

l2cap_le_flowctl_init() can cause both div-by-zero and an integer
overflow since hdev->le_mtu may not fall in the valid range in the
specification.

Move MTU from hci_dev to hci_conn to validate MTU and stop the connection
process earlier if MTU is invalid.
Also, add a missing validation in read_buffer_size() and make it return
an error value if the validation fails.
Now hci_conn_add() returns ERR_PTR() as it can fail due to the both a
kzalloc failure and invalid MTU value.

divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G        W          6.9.0-rc5+ #20
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Workqueue: hci0 hci_rx_work
RIP: 0010:l2cap_le_flowctl_init+0x19e/0x3f0 net/bluetooth/l2cap_core.c:547
Code: e8 17 17 0c 00 66 41 89 9f 84 00 00 00 bf 01 00 00 00 41 b8 02 00 00 00 4c 89 fe 4c 89 e2 89 d9 e8 27 17 0c 00 44 89 f0 31 d2 <66> f7 f3 89 c3 ff c3 4d 8d b7 88 00 00 00 4c 89 f0 48 c1 e8 03 42
RSP: 0018:ffff88810bc0f858 EFLAGS: 00010246
RAX: 00000000000002a0 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff88810bc0f7c0 RDI: ffffc90002dcb66f
RBP: ffff88810bc0f880 R08: aa69db2dda70ff01 R09: 0000ffaaaaaaaaaa
R10: 0084000000ffaaaa R11: 0000000000000000 R12: ffff88810d65a084
R13: dffffc0000000000 R14: 00000000000002a0 R15: ffff88810d65a000
FS:  0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000100 CR3: 0000000103268003 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
 <TASK>
 l2cap_le_connect_req net/bluetooth/l2cap_core.c:4902 [inline]
 l2cap_le_sig_cmd net/bluetooth/l2cap_core.c:5420 [inline]
 l2cap_le_sig_channel net/bluetooth/l2cap_core.c:5486 [inline]
 l2cap_recv_frame+0xe59d/0x11710 net/bluetooth/l2cap_core.c:6809
 l2cap_recv_acldata+0x544/0x10a0 net/bluetooth/l2cap_core.c:7506
 hci_acldata_packet net/bluetooth/hci_core.c:3939 [inline]
 hci_rx_work+0x5e5/0xb20 net/bluetooth/hci_core.c:4176
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x90f/0x1530 kernel/workqueue.c:3335
 worker_thread+0x926/0xe70 kernel/workqueue.c:3416
 kthread+0x2e3/0x380 kernel/kthread.c:388
 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---

Signed-off-by: Sungwoo Kim <[e-mail]>
---
v1 -> v2:
- Reply with an error code if a given MTU is not valid.
- Refuse hcon allocation if MTU is not still valid.
v2 -> v3:
- Move mtu to hcon.
- Make SCO, ISO, and L2CAP use hcon->mtu.

 include/net/bluetooth/hci.h      |  9 ++++
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_conn.c         | 75 ++++++++++++++++++++++----------
 net/bluetooth/hci_event.c        | 35 ++++++++++-----
 net/bluetooth/iso.c              |  2 +-
 net/bluetooth/l2cap_core.c       | 17 ++------
 net/bluetooth/sco.c              |  6 +--
 7 files changed, 91 insertions(+), 54 deletions(-)

Comments

[e-mail] May 4, 2024, 6:37 p.m. UTC | #1

This is an automated email and please do not reply to this email.

Dear Submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
While preparing the CI tests, the patches you submitted couldn't be applied to the current HEAD of the repository.

----- Output -----

error: patch failed: net/bluetooth/hci_event.c:6498
error: net/bluetooth/hci_event.c: patch does not apply
hint: Use 'git am --show-current-patch' to see the failed patch

Please resolve the issue and submit the patches again.


---
Regards,
Linux Bluetooth

Patch

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 5c12761cb..07198beb3 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1666,6 +1666,15 @@  struct hci_cp_le_set_event_mask {
 	__u8     mask[8];
 } __packed;
 
+/* BLUETOOTH CORE SPECIFICATION Version 5.4 | Vol 4, Part E
+ * 7.8.2 LE Read Buffer Size command
+ * MAX_LE_MTU is 0xffff.
+ * 0 is also valid. It means that no dedicated LE Buffer exists.
+ * It should use the HCI_Read_Buffer_Size command and mtu is shared
+ * between BR/EDR and LE.
+ */
+#define HCI_MIN_LE_MTU 0x001b
+
 #define HCI_OP_LE_READ_BUFFER_SIZE	0x2002
 struct hci_rp_le_read_buffer_size {
 	__u8     status;
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index e8f581f3f..b1c8489ff 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -706,6 +706,7 @@  struct hci_conn {
 	__u16		handle;
 	__u16		sync_handle;
 	__u16		state;
+	__u16		mtu;
 	__u8		mode;
 	__u8		type;
 	__u8		role;
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 05346250f..6ab404dda 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -909,11 +909,37 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 {
 	struct hci_conn *conn;
 
+	switch (type) {
+	case ACL_LINK:
+		if (!hdev->acl_mtu)
+			return ERR_PTR(-ECONNREFUSED);
+		break;
+	case ISO_LINK:
+		if (hdev->iso_mtu)
+			/* Dedicated ISO Buffer exists */
+			break;
+		fallthrough;
+	case LE_LINK:
+		if (hdev->le_mtu && hdev->le_mtu < HCI_MIN_LE_MTU)
+			return ERR_PTR(-ECONNREFUSED);
+		if (!hdev->le_mtu && hdev->acl_mtu < HCI_MIN_LE_MTU)
+			return ERR_PTR(-ECONNREFUSED);
+		break;
+	case SCO_LINK:
+	case ESCO_LINK:
+		if (!hdev->sco_pkts)
+			/* Controller does not support SCO or eSCO over HCI */
+			return ERR_PTR(-ECONNREFUSED);
+		break;
+	default:
+		return ERR_PTR(-ECONNREFUSED);
+	}
+
 	bt_dev_dbg(hdev, "dst %pMR handle 0x%4.4x", dst, handle);
 
 	conn = kzalloc(sizeof(*conn), GFP_KERNEL);
 	if (!conn)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	bacpy(&conn->dst, dst);
 	bacpy(&conn->src, &hdev->bdaddr);
@@ -944,10 +970,12 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 	switch (type) {
 	case ACL_LINK:
 		conn->pkt_type = hdev->pkt_type & ACL_PTYPE_MASK;
+		conn->mtu = hdev->acl_mtu;
 		break;
 	case LE_LINK:
 		/* conn->src should reflect the local identity address */
 		hci_copy_identity_address(hdev, &conn->src, &conn->src_type);
+		conn->mtu = hdev->le_mtu ? hdev->le_mtu : hdev->acl_mtu;
 		break;
 	case ISO_LINK:
 		/* conn->src should reflect the local identity address */
@@ -959,6 +987,8 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 		else if (conn->role == HCI_ROLE_MASTER)
 			conn->cleanup = cis_cleanup;
 
+		conn->mtu = hdev->iso_mtu ? hdev->iso_mtu :
+			    hdev->le_mtu ? hdev->le_mtu : hdev->acl_mtu;
 		break;
 	case SCO_LINK:
 		if (lmp_esco_capable(hdev))
@@ -966,9 +996,12 @@  struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst,
 					(hdev->esco_type & EDR_ESCO_MASK);
 		else
 			conn->pkt_type = hdev->pkt_type & SCO_PTYPE_MASK;
+
+		conn->mtu = hdev->sco_mtu;
 		break;
 	case ESCO_LINK:
 		conn->pkt_type = hdev->esco_type & ~EDR_ESCO_MASK;
+		conn->mtu = hdev->sco_mtu;
 		break;
 	}
 
@@ -1011,7 +1044,7 @@  struct hci_conn *hci_conn_add_unset(struct hci_dev *hdev, int type,
 
 	handle = hci_conn_hash_alloc_unset(hdev);
 	if (unlikely(handle < 0))
-		return NULL;
+		return ERR_PTR(-ECONNREFUSED);
 
 	return hci_conn_add(hdev, type, dst, role, handle);
 }
@@ -1317,8 +1350,8 @@  struct hci_conn *hci_connect_le(struct hci_dev *hdev, bdaddr_t *dst,
 		bacpy(&conn->dst, dst);
 	} else {
 		conn = hci_conn_add_unset(hdev, LE_LINK, dst, role);
-		if (!conn)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(conn))
+			return conn;
 		hci_conn_hold(conn);
 		conn->pending_sec_level = sec_level;
 	}
@@ -1494,8 +1527,8 @@  static struct hci_conn *hci_add_bis(struct hci_dev *hdev, bdaddr_t *dst,
 		return ERR_PTR(-EADDRINUSE);
 
 	conn = hci_conn_add_unset(hdev, ISO_LINK, dst, HCI_ROLE_MASTER);
-	if (!conn)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(conn))
+		return conn;
 
 	conn->state = BT_CONNECT;
 
@@ -1538,8 +1571,8 @@  struct hci_conn *hci_connect_le_scan(struct hci_dev *hdev, bdaddr_t *dst,
 	BT_DBG("requesting refresh of dst_addr");
 
 	conn = hci_conn_add_unset(hdev, LE_LINK, dst, HCI_ROLE_MASTER);
-	if (!conn)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(conn))
+		return conn;
 
 	if (hci_explicit_conn_params_set(hdev, dst, dst_type) < 0) {
 		hci_conn_del(conn);
@@ -1586,8 +1619,8 @@  struct hci_conn *hci_connect_acl(struct hci_dev *hdev, bdaddr_t *dst,
 	acl = hci_conn_hash_lookup_ba(hdev, ACL_LINK, dst);
 	if (!acl) {
 		acl = hci_conn_add_unset(hdev, ACL_LINK, dst, HCI_ROLE_MASTER);
-		if (!acl)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(acl))
+			return acl;
 	}
 
 	hci_conn_hold(acl);
@@ -1655,9 +1688,9 @@  struct hci_conn *hci_connect_sco(struct hci_dev *hdev, int type, bdaddr_t *dst,
 	sco = hci_conn_hash_lookup_ba(hdev, type, dst);
 	if (!sco) {
 		sco = hci_conn_add_unset(hdev, type, dst, HCI_ROLE_MASTER);
-		if (!sco) {
+		if (IS_ERR(sco)) {
 			hci_conn_drop(acl);
-			return ERR_PTR(-ENOMEM);
+			return sco;
 		}
 	}
 
@@ -1847,8 +1880,8 @@  struct hci_conn *hci_bind_cis(struct hci_dev *hdev, bdaddr_t *dst,
 				       qos->ucast.cis);
 	if (!cis) {
 		cis = hci_conn_add_unset(hdev, ISO_LINK, dst, HCI_ROLE_MASTER);
-		if (!cis)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(cis))
+			return cis;
 		cis->cleanup = cis_cleanup;
 		cis->dst_type = dst_type;
 		cis->iso_qos.ucast.cig = BT_ISO_QOS_CIG_UNSET;
@@ -1983,14 +2016,8 @@  static void hci_iso_qos_setup(struct hci_dev *hdev, struct hci_conn *conn,
 			      struct bt_iso_io_qos *qos, __u8 phy)
 {
 	/* Only set MTU if PHY is enabled */
-	if (!qos->sdu && qos->phy) {
-		if (hdev->iso_mtu > 0)
-			qos->sdu = hdev->iso_mtu;
-		else if (hdev->le_mtu > 0)
-			qos->sdu = hdev->le_mtu;
-		else
-			qos->sdu = hdev->acl_mtu;
-	}
+	if (!qos->sdu && qos->phy)
+		qos->sdu = conn->mtu;
 
 	/* Use the same PHY as ACL if set to any */
 	if (qos->phy == BT_ISO_PHY_ANY)
@@ -2071,8 +2098,8 @@  struct hci_conn *hci_pa_create_sync(struct hci_dev *hdev, bdaddr_t *dst,
 		return ERR_PTR(-EBUSY);
 
 	conn = hci_conn_add_unset(hdev, ISO_LINK, dst, HCI_ROLE_SLAVE);
-	if (!conn)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(conn))
+		return conn;
 
 	conn->iso_qos = *qos;
 	conn->state = BT_LISTEN;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 4a27e4a17..4ad4a365c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -954,6 +954,9 @@  static u8 hci_cc_read_buffer_size(struct hci_dev *hdev, void *data,
 	BT_DBG("%s acl mtu %d:%d sco mtu %d:%d", hdev->name, hdev->acl_mtu,
 	       hdev->acl_pkts, hdev->sco_mtu, hdev->sco_pkts);
 
+	if (!hdev->acl_mtu || !hdev->acl_pkts)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -1263,6 +1266,9 @@  static u8 hci_cc_le_read_buffer_size(struct hci_dev *hdev, void *data,
 
 	BT_DBG("%s le mtu %d:%d", hdev->name, hdev->le_mtu, hdev->le_pkts);
 
+	if (hdev->le_mtu && hdev->le_mtu < HCI_MIN_LE_MTU)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -2342,8 +2348,8 @@  static void hci_cs_create_conn(struct hci_dev *hdev, __u8 status)
 		if (!conn) {
 			conn = hci_conn_add_unset(hdev, ACL_LINK, &cp->bdaddr,
 						  HCI_ROLE_MASTER);
-			if (!conn)
-				bt_dev_err(hdev, "no memory for new connection");
+			if (IS_ERR(conn))
+				bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 		}
 	}
 
@@ -3154,8 +3160,8 @@  static void hci_conn_complete_evt(struct hci_dev *hdev, void *data,
 						      BDADDR_BREDR)) {
 			conn = hci_conn_add_unset(hdev, ev->link_type,
 						  &ev->bdaddr, HCI_ROLE_SLAVE);
-			if (!conn) {
-				bt_dev_err(hdev, "no memory for new conn");
+			if (IS_ERR(conn)) {
+				bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 				goto unlock;
 			}
 		} else {
@@ -3343,8 +3349,8 @@  static void hci_conn_request_evt(struct hci_dev *hdev, void *data,
 	if (!conn) {
 		conn = hci_conn_add_unset(hdev, ev->link_type, &ev->bdaddr,
 					  HCI_ROLE_SLAVE);
-		if (!conn) {
-			bt_dev_err(hdev, "no memory for new connection");
+		if (IS_ERR(conn)) {
+			bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 			goto unlock;
 		}
 	}
@@ -3821,6 +3827,9 @@  static u8 hci_cc_le_read_buffer_size_v2(struct hci_dev *hdev, void *data,
 	BT_DBG("%s acl mtu %d:%d iso mtu %d:%d", hdev->name, hdev->acl_mtu,
 	       hdev->acl_pkts, hdev->iso_mtu, hdev->iso_pkts);
 
+	if (hdev->le_mtu && hdev->le_mtu < HCI_MIN_LE_MTU)
+		return HCI_ERROR_INVALID_PARAMETERS;
+
 	return rp->status;
 }
 
@@ -5768,8 +5777,8 @@  static void le_conn_complete_evt(struct hci_dev *hdev, u8 status,
 			goto unlock;
 
 		conn = hci_conn_add_unset(hdev, LE_LINK, bdaddr, role);
-		if (!conn) {
-			bt_dev_err(hdev, "no memory for new connection");
+		if (IS_ERR(conn)) {
+			bt_dev_err(hdev, "connection err: %ld", PTR_ERR(conn));
 			goto unlock;
 		}
 
@@ -6498,7 +6507,7 @@  static void hci_le_pa_sync_estabilished_evt(struct hci_dev *hdev, void *data,
 		pa_sync = hci_conn_add_unset(hdev, ISO_LINK, BDADDR_ANY,
 					     HCI_ROLE_SLAVE);
 
-		if (!pa_sync)
+		if (IS_ERR(pa_sync))
 			goto unlock;
 
 		set_bit(HCI_CONN_PA_SYNC_FAILED, &pa_sync->flags);
@@ -6898,7 +6907,7 @@  static void hci_le_cis_req_evt(struct hci_dev *hdev, void *data,
 	if (!cis) {
 		cis = hci_conn_add(hdev, ISO_LINK, &acl->dst, HCI_ROLE_SLAVE,
 				   cis_handle);
-		if (!cis) {
+		if (IS_ERR(cis)) {
 			hci_le_reject_cis(hdev, ev->cis_handle);
 			goto unlock;
 		}
@@ -7007,7 +7016,7 @@  static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
 		if (!bis) {
 			bis = hci_conn_add(hdev, ISO_LINK, BDADDR_ANY,
 					   HCI_ROLE_SLAVE, handle);
-			if (!bis)
+			if (IS_ERR(bis))
 				continue;
 		}
 
@@ -7037,6 +7046,8 @@  static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
 			u16 handle = le16_to_cpu(ev->bis[i]);
 
 			bis = hci_conn_hash_lookup_handle(hdev, handle);
+			if (!bis)
+				continue;
 
 			set_bit(HCI_CONN_BIG_SYNC_FAILED, &bis->flags);
 			hci_connect_cfm(bis, ev->status);
@@ -7077,7 +7088,7 @@  static void hci_le_big_info_adv_report_evt(struct hci_dev *hdev, void *data,
 	pa_sync = hci_conn_add_unset(hdev, ISO_LINK, BDADDR_ANY,
 				     HCI_ROLE_SLAVE);
 
-	if (!pa_sync)
+	if (IS_ERR(pa_sync))
 		goto unlock;
 
 	pa_sync->sync_handle = le16_to_cpu(ev->sync_handle);
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index ef0cc80b4..6bed4aa82 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -1285,7 +1285,7 @@  static int iso_sock_sendmsg(struct socket *sock, struct msghdr *msg,
 		return -ENOTCONN;
 	}
 
-	mtu = iso_pi(sk)->conn->hcon->hdev->iso_mtu;
+	mtu = iso_pi(sk)->conn->hcon->mtu;
 
 	release_sock(sk);
 
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 84fc70862..d2a0bc09f 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -6239,7 +6239,7 @@  static int l2cap_finish_move(struct l2cap_chan *chan)
 	BT_DBG("chan %p", chan);
 
 	chan->rx_state = L2CAP_RX_STATE_RECV;
-	chan->conn->mtu = chan->conn->hcon->hdev->acl_mtu;
+	chan->conn->mtu = chan->conn->hcon->mtu;
 
 	return l2cap_resegment(chan);
 }
@@ -6306,7 +6306,7 @@  static int l2cap_rx_state_wait_f(struct l2cap_chan *chan,
 	 */
 	chan->next_tx_seq = control->reqseq;
 	chan->unacked_frames = 0;
-	chan->conn->mtu = chan->conn->hcon->hdev->acl_mtu;
+	chan->conn->mtu = chan->conn->hcon->mtu;
 
 	err = l2cap_resegment(chan);
 
@@ -6846,18 +6846,7 @@  static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon)
 
 	BT_DBG("hcon %p conn %p hchan %p", hcon, conn, hchan);
 
-	switch (hcon->type) {
-	case LE_LINK:
-		if (hcon->hdev->le_mtu) {
-			conn->mtu = hcon->hdev->le_mtu;
-			break;
-		}
-		fallthrough;
-	default:
-		conn->mtu = hcon->hdev->acl_mtu;
-		break;
-	}
-
+	conn->mtu = hcon->mtu;
 	conn->feat_mask = 0;
 
 	conn->local_fixed_chan = L2CAP_FC_SIG_BREDR | L2CAP_FC_CONNLESS;
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 5d03c5440..8718652ee 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -122,7 +122,6 @@  static void sco_sock_clear_timer(struct sock *sk)
 /* ---- SCO connections ---- */
 static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
 {
-	struct hci_dev *hdev = hcon->hdev;
 	struct sco_conn *conn = hcon->sco_data;
 
 	if (conn) {
@@ -140,9 +139,10 @@  static struct sco_conn *sco_conn_add(struct hci_conn *hcon)
 
 	hcon->sco_data = conn;
 	conn->hcon = hcon;
+	conn->mtu = hcon->mtu;
 
-	if (hdev->sco_mtu > 0)
-		conn->mtu = hdev->sco_mtu;
+	if (hcon->mtu > 0)
+		conn->mtu = hcon->mtu;
 	else
 		conn->mtu = 60;