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ANDROID: binder: prevent transactions into own process.

PATCH Superseded Martijn Coenen 1 participant 1 message Mar 28, 2018 Android drivers

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PATCH v2 1/1 ANDROID: binder: prevent transactions into own process.

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.

---
Changed in v2:
- Use target_proc directly to avoid dereference.

 drivers/android/binder.c | 8 ++++++++
 1 file changed, 8 insertions(+)
drivers/android/binder.c +8 -0
index 764b63a5aade..e578eee31589 100644
@@ -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) {
 			/*
Signature · 1 line
2.17.0.rc1.321.gba9d0f2565-goog