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Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()
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commit a5b862c upstream.

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.

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 [starfive-tech#1] PREEMPT SMP KASAN NOPTI
CPU: 0 PID: 67 Comm: kworker/u5:0 Tainted: G        W          6.9.0-rc5+ starfive-tech#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 ]---

Fixes: 6ed58ec ("Bluetooth: Use LE buffers for LE traffic")
Suggested-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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swkim101 authored and gregkh committed May 25, 2024
1 parent 7a4b16f commit d2b2f7d
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Showing 7 changed files with 88 additions and 53 deletions.
9 changes: 9 additions & 0 deletions include/net/bluetooth/hci.h
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
1 change: 1 addition & 0 deletions include/net/bluetooth/hci_core.h
Original file line number Diff line number Diff line change
Expand Up @@ -706,6 +706,7 @@ struct hci_conn {
__u16 handle;
__u16 sync_handle;
__u16 state;
__u16 mtu;
__u8 mode;
__u8 type;
__u8 role;
Expand Down
75 changes: 51 additions & 24 deletions net/bluetooth/hci_conn.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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 */
Expand All @@ -959,16 +987,21 @@ 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))
conn->pkt_type = (hdev->esco_type & SCO_ESCO_MASK) |
(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;
}

Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;
}
}

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down
31 changes: 20 additions & 11 deletions net/bluetooth/hci_event.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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));
}
}

Expand Down Expand Up @@ -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 {
Expand Down Expand Up @@ -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;
}
}
Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
}

Expand Down Expand Up @@ -7079,7 +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);
Expand Down
2 changes: 1 addition & 1 deletion net/bluetooth/iso.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand Down
17 changes: 3 additions & 14 deletions net/bluetooth/l2cap_core.c
Original file line number Diff line number Diff line change
Expand Up @@ -6241,7 +6241,7 @@ 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);
}
Expand Down Expand Up @@ -6308,7 +6308,7 @@ 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);

Expand Down Expand Up @@ -6848,18 +6848,7 @@ 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;
Expand Down
6 changes: 3 additions & 3 deletions net/bluetooth/sco.c
Original file line number Diff line number Diff line change
Expand Up @@ -126,7 +126,6 @@ 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) {
Expand All @@ -144,9 +143,10 @@ 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;

Expand Down

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