5.4-stable review patch. If anyone has any objections, please let me know.
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From: Ivan Pravdin ipravdin.official@gmail.com
[ Upstream commit ca94b2b036c22556c3a66f1b80f490882deef7a6 ]
Currently, bcsp_recv() can be called even when the BCSP protocol has not been registered. This leads to a NULL pointer dereference, as shown in the following stack trace:
KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:bcsp_recv+0x13d/0x1740 drivers/bluetooth/hci_bcsp.c:590 Call Trace: <TASK> hci_uart_tty_receive+0x194/0x220 drivers/bluetooth/hci_ldisc.c:627 tiocsti+0x23c/0x2c0 drivers/tty/tty_io.c:2290 tty_ioctl+0x626/0xde0 drivers/tty/tty_io.c:2706 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
To prevent this, ensure that the HCI_UART_REGISTERED flag is set before processing received data. If the protocol is not registered, return -EUNATCH.
Reported-by: syzbot+4ed6852d4da4606c93da@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4ed6852d4da4606c93da Tested-by: syzbot+4ed6852d4da4606c93da@syzkaller.appspotmail.com Signed-off-by: Ivan Pravdin ipravdin.official@gmail.com Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/bluetooth/hci_bcsp.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/bluetooth/hci_bcsp.c b/drivers/bluetooth/hci_bcsp.c index 8055f63603f45..8ff69111ceede 100644 --- a/drivers/bluetooth/hci_bcsp.c +++ b/drivers/bluetooth/hci_bcsp.c @@ -582,6 +582,9 @@ static int bcsp_recv(struct hci_uart *hu, const void *data, int count) struct bcsp_struct *bcsp = hu->priv; const unsigned char *ptr;
+ if (!test_bit(HCI_UART_REGISTERED, &hu->flags)) + return -EUNATCH; + BT_DBG("hu %p count %d rx_state %d rx_count %ld", hu, count, bcsp->rx_state, bcsp->rx_count);