0f296e782f
This bug report came up when we were testing the device driver by fuzzing. It shows that buf1_len can get underflowed and be 0xfffffffc (4294967292). This bug is triggerable with a compromised/malfunctioning device. We found the bug through QEMU emulation tested the patch with emulation. We did NOT test it on real hardware. Attached is the bug report by fuzzing. BUG: KASAN: use-after-free in stmmac_napi_poll_rx+0x1c08/0x36e0 [stmmac] Read of size 4294967292 at addr ffff888016358000 by task ksoftirqd/0/9 CPU: 0 PID: 9 Comm: ksoftirqd/0 Tainted: G W 5.6.0 #1 Call Trace: dump_stack+0x76/0xa0 print_address_description.constprop.0+0x16/0x200 ? stmmac_napi_poll_rx+0x1c08/0x36e0 [stmmac] ? stmmac_napi_poll_rx+0x1c08/0x36e0 [stmmac] __kasan_report.cold+0x37/0x7c ? stmmac_napi_poll_rx+0x1c08/0x36e0 [stmmac] kasan_report+0xe/0x20 check_memory_region+0x15a/0x1d0 memcpy+0x20/0x50 stmmac_napi_poll_rx+0x1c08/0x36e0 [stmmac] ? stmmac_suspend+0x850/0x850 [stmmac] ? __next_timer_interrupt+0xba/0xf0 net_rx_action+0x363/0xbd0 ? call_timer_fn+0x240/0x240 ? __switch_to_asm+0x40/0x70 ? napi_busy_loop+0x520/0x520 ? __schedule+0x839/0x15a0 __do_softirq+0x18c/0x634 ? takeover_tasklets+0x5f0/0x5f0 run_ksoftirqd+0x15/0x20 smpboot_thread_fn+0x2f1/0x6b0 ? smpboot_unregister_percpu_thread+0x160/0x160 ? __kthread_parkme+0x80/0x100 ? smpboot_unregister_percpu_thread+0x160/0x160 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: David S. Miller <davem@davemloft.net>
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.