From: Ziyang Xuan william.xuanziyang@huawei.com
commit 15c9a359094ec6251578b02387436bc64f11a477 upstream.
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)") Cc: stable stable@vger.kernel.org Acked-by: Eli Billauer eli.billauer@gmail.com Signed-off-by: Ziyang Xuan william.xuanziyang@huawei.com Link: https://lore.kernel.org/r/20211016052047.1611983-1-william.xuanziyang@huawei... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/xillybus/xillyusb.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/char/xillybus/xillyusb.c +++ b/drivers/char/xillybus/xillyusb.c @@ -1912,6 +1912,7 @@ static int xillyusb_setup_base_eps(struc
dealloc: endpoint_dealloc(xdev->msg_ep); /* Also frees FIFO mem if allocated */ + xdev->msg_ep = NULL; return -ENOMEM; }