f1cb3476e4
rsi_get_* functions rely on an offset variable from usb input. The size of usb input is RSI_MAX_RX_USB_PKT_SIZE(3000), while 2-byte offset can be up to 0xFFFF. Thus a large offset can cause out-of-bounds read. The patch adds a bound checking condition when rcv_pkt_len is 0, indicating it's USB. It's unclear whether this is triggerable from other type of bus. The following check might help in that case. offset > rcv_pkt_len - FRAME_DESC_SZ The bug is trigerrable with conpromised/malfunctioning USB devices. I tested the patch with the crashing input and got no more bug report. Attached is the KASAN report from fuzzing. BUG: KASAN: slab-out-of-bounds in rsi_read_pkt+0x42e/0x500 [rsi_91x] Read of size 2 at addr ffff888019439fdb by task RX-Thread/227 CPU: 0 PID: 227 Comm: RX-Thread Not tainted 5.6.0 #66 Call Trace: dump_stack+0x76/0xa0 print_address_description.constprop.0+0x16/0x200 ? rsi_read_pkt+0x42e/0x500 [rsi_91x] ? rsi_read_pkt+0x42e/0x500 [rsi_91x] __kasan_report.cold+0x37/0x7c ? rsi_read_pkt+0x42e/0x500 [rsi_91x] kasan_report+0xe/0x20 rsi_read_pkt+0x42e/0x500 [rsi_91x] rsi_usb_rx_thread+0x1b1/0x2fc [rsi_usb] ? rsi_probe+0x16a0/0x16a0 [rsi_usb] ? _raw_spin_lock_irqsave+0x7b/0xd0 ? _raw_spin_trylock_bh+0x120/0x120 ? __wake_up_common+0x10b/0x520 ? rsi_probe+0x16a0/0x16a0 [rsi_usb] kthread+0x2b5/0x3b0 ? kthread_create_on_node+0xd0/0xd0 ret_from_fork+0x22/0x40 Reported-by: Brendan Dolan-Gavitt <brendandg@nyu.edu> Signed-off-by: Zekun Shen <bruceshenzk@gmail.com> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Link: https://lore.kernel.org/r/YXxXS4wgu2OsmlVv@10-18-43-117.dynapool.wireless.nyu.edu
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.