Ivan Pravdin 799cd62cbc Bluetooth: bcsp: receive data only if registered
[ Upstream commit ca94b2b036 ]

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>
2025-11-24 10:29:45 +01:00
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2025-11-02 22:14:42 +09:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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