CVE-2024-36968

In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix div-by-zero in l2cap_le_flowctl_init()
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 ]—