[PATCH 6.9 07/25] Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()

6.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Sungwoo Kim iam@sung-woo.kim

commit a5b862c6a221459d54e494e88965b48dcfa6cc44 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 [#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 ]---

Fixes: 6ed58ec520ad ("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 --- include/net/bluetooth/hci.h | 9 ++++ include/net/bluetooth/hci_core.h | 1 net/bluetooth/hci_conn.c | 75 ++++++++++++++++++++++++++------------- net/bluetooth/hci_event.c | 31 ++++++++++------ net/bluetooth/iso.c | 2 - net/bluetooth/l2cap_core.c | 17 +------- net/bluetooth/sco.c | 6 +-- 7 files changed, 88 insertions(+), 53 deletions(-)

--- 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; --- 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; --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -909,11 +909,37 @@ struct hci_conn *hci_conn_add(struct hci { 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 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 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 (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(stru

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 h 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(stru 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(str 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 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 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 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 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(stru 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; --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -954,6 +954,9 @@ static u8 hci_cc_read_buffer_size(struct 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(str

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 hc 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 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 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( 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 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; }

@@ -6898,7 +6907,7 @@ static void hci_le_cis_req_evt(struct hc 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_ if (!bis) { bis = hci_conn_add(hdev, ISO_LINK, BDADDR_ANY, HCI_ROLE_SLAVE, handle); - if (!bis) + if (IS_ERR(bis)) continue; }

@@ -7079,7 +7088,7 @@ static void hci_le_big_info_adv_report_e 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); --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -1285,7 +1285,7 @@ static int iso_sock_sendmsg(struct socke return -ENOTCONN; }

- mtu = iso_pi(sk)->conn->hcon->hdev->iso_mtu; + mtu = iso_pi(sk)->conn->hcon->mtu;

release_sock(sk);

--- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -6241,7 +6241,7 @@ static int l2cap_finish_move(struct l2ca 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); } @@ -6308,7 +6308,7 @@ static int l2cap_rx_state_wait_f(struct */ 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);

@@ -6848,18 +6848,7 @@ static struct l2cap_conn *l2cap_conn_add

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; --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -126,7 +126,6 @@ static void sco_sock_clear_timer(struct /* ---- 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) { @@ -144,9 +143,10 @@ static struct sco_conn *sco_conn_add(str

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;