This can't happen with normal nodes (because you can't get a ref
to a node you own), but it could happen with the context manager;
to make the behavior consistent with regular nodes, reject
transactions into the context manager by the process owning it.

Reported-by: syzbot+09e05aba06723a94d...@syzkaller.appspotmail.com
Signed-off-by: Martijn Coenen <m...@android.com>
---
 drivers/android/binder.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 764b63a5aade..e578eee31589 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2839,6 +2839,14 @@ static void binder_transaction(struct binder_proc *proc,
                        else
                                return_error = BR_DEAD_REPLY;
                        mutex_unlock(&context->context_mgr_node_lock);
+                       if (target_node && target_proc == proc) {
+                               binder_user_error("%d:%d got transaction to 
context manager from process owning it\n",
+                                                 proc->pid, thread->pid);
+                               return_error = BR_FAILED_REPLY;
+                               return_error_param = -EINVAL;
+                               return_error_line = __LINE__;
+                               goto err_invalid_target_handle;
+                       }
                }
                if (!target_node) {
                        /*
-- 
2.17.0.rc1.321.gba9d0f2565-goog

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