binder: fix atomic sleep when get extended error

binder_inner_proc_lock(thread->proc) is a spin lock, copy_to_user can't
be called with in this lock.

Copy it as a local variable to fix it.

Fixes: bd32889e841c ("binder: add BINDER_GET_EXTENDED_ERROR ioctl")
Reported-by: syzbot+46fff6434a7f968ecb39@syzkaller.appspotmail.com
Reviewed-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Schspa Shi <schspa@gmail.com>
Link: https://lore.kernel.org/r/20220518011754.49348-1-schspa@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 9e36608..77d0b17 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -5163,19 +5163,16 @@ static int binder_ioctl_get_freezer_info(
 static int binder_ioctl_get_extended_error(struct binder_thread *thread,
                                           void __user *ubuf)
 {
-       struct binder_extended_error *ee = &thread->ee;
+       struct binder_extended_error ee;
 
        binder_inner_proc_lock(thread->proc);
-       if (copy_to_user(ubuf, ee, sizeof(*ee))) {
-               binder_inner_proc_unlock(thread->proc);
-               return -EFAULT;
-       }
-
-       ee->id = 0;
-       ee->command = BR_OK;
-       ee->param = 0;
+       ee = thread->ee;
+       binder_set_extended_error(&thread->ee, 0, BR_OK, 0);
        binder_inner_proc_unlock(thread->proc);
 
+       if (copy_to_user(ubuf, &ee, sizeof(ee)))
+               return -EFAULT;
+
        return 0;
 }