b07e3c6ebc
When freeing rx_cb->rx_skb, the pointer is not set to NULL, a later rsi_rx_done_handler call will try to read the freed address. This bug will very likley lead to double free, although detected early as use-after-free bug. The bug is triggerable with a compromised/malfunctional usb device. After applying the patch, the same input no longer triggers the use-after-free. Attached is the kasan report from fuzzing. BUG: KASAN: use-after-free in rsi_rx_done_handler+0x354/0x430 [rsi_usb] Read of size 4 at addr ffff8880188e5930 by task modprobe/231 Call Trace: <IRQ> dump_stack+0x76/0xa0 print_address_description.constprop.0+0x16/0x200 ? rsi_rx_done_handler+0x354/0x430 [rsi_usb] ? rsi_rx_done_handler+0x354/0x430 [rsi_usb] __kasan_report.cold+0x37/0x7c ? dma_direct_unmap_page+0x90/0x110 ? rsi_rx_done_handler+0x354/0x430 [rsi_usb] kasan_report+0xe/0x20 rsi_rx_done_handler+0x354/0x430 [rsi_usb] __usb_hcd_giveback_urb+0x1e4/0x380 usb_giveback_urb_bh+0x241/0x4f0 ? __usb_hcd_giveback_urb+0x380/0x380 ? apic_timer_interrupt+0xa/0x20 tasklet_action_common.isra.0+0x135/0x330 __do_softirq+0x18c/0x634 ? handle_irq_event+0xcd/0x157 ? handle_edge_irq+0x1eb/0x7b0 irq_exit+0x114/0x140 do_IRQ+0x91/0x1e0 common_interrupt+0xf/0xf </IRQ> 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/YXxQL/vIiYcZUu/j@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.