Messages in this thread | | | Date | Sat, 16 Oct 2021 18:43:43 +0300 | From | Eli Billauer <> | Subject | Re: [PATCH] char: xillybus: fix msg_ep UAF in xillyusb_probe() |
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Correct. Thanks a lot.
Acked-by: Eli Billauer <eli.billauer@gmail.com>
On 16/10/21 08:20, Ziyang Xuan wrote: > When endpoint_alloc() return failed in xillyusb_setup_base_eps(), > 'xdev->msg_ep' will be freed but not set to NULL. That lets program > enter fail handling to cleanup_dev() in xillyusb_probe(). Check for > 'xdev->msg_ep' is invalid in cleanup_dev() because 'xdev->msg_ep' did > not set to NULL when was freed. So the UAF problem for 'xdev->msg_ep' > is triggered. > > ================================================================== > BUG: KASAN: use-after-free in fifo_mem_release+0x1f4/0x210 > CPU: 0 PID: 166 Comm: kworker/0:2 Not tainted 5.15.0-rc5+ #19 > Call Trace: > dump_stack_lvl+0xe2/0x152 > print_address_description.constprop.0+0x21/0x140 > ? fifo_mem_release+0x1f4/0x210 > kasan_report.cold+0x7f/0x11b > ? xillyusb_probe+0x530/0x700 > ? fifo_mem_release+0x1f4/0x210 > fifo_mem_release+0x1f4/0x210 > ? __sanitizer_cov_trace_pc+0x1d/0x50 > endpoint_dealloc+0x35/0x2b0 > cleanup_dev+0x90/0x120 > xillyusb_probe+0x59a/0x700 > ... > > Freed by task 166: > kasan_save_stack+0x1b/0x40 > kasan_set_track+0x1c/0x30 > kasan_set_free_info+0x20/0x30 > __kasan_slab_free+0x109/0x140 > kfree+0x117/0x4c0 > xillyusb_probe+0x606/0x700 > > Set 'xdev->msg_ep' to NULL after being freed in xillyusb_setup_base_eps() > to fix the UAF problem. > > Fixes: a53d1202aef1 ("char: xillybus: Add driver for XillyUSB (Xillybus variant for USB)") > Signed-off-by: Ziyang Xuan<william.xuanziyang@huawei.com> > --- > drivers/char/xillybus/xillyusb.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/char/xillybus/xillyusb.c b/drivers/char/xillybus/xillyusb.c > index e7f88f35c702..dc3551796e5e 100644 > --- a/drivers/char/xillybus/xillyusb.c > +++ b/drivers/char/xillybus/xillyusb.c > @@ -1912,6 +1912,7 @@ static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev) > > dealloc: > endpoint_dealloc(xdev->msg_ep); /* Also frees FIFO mem if allocated */ > + xdev->msg_ep = NULL; > return -ENOMEM; > } > >
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