ANDROID: binder: fix transaction leak.

If a call to put_user() fails, we failed to
properly free a transaction and send a failed
reply (if necessary).

Bug: 63117588
Test: binderLibTest

Change-Id: Ia98db8cd82ce354a4cdc8811c969988d585c7e31
Signed-off-by: Martijn Coenen <maco@android.com>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index d163ebcce27ce7e1ce53f7cae219b9b1dedf108e..1b46e4cce926640d43c1d86cf2146a0206cc23d9 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2113,6 +2113,26 @@ static void binder_send_failed_reply(struct binder_transaction *t,
        }
 }
 
+/**
+ * binder_cleanup_transaction() - cleans up undelivered transaction
+ * @t:         transaction that needs to be cleaned up
+ * @reason:    reason the transaction wasn't delivered
+ * @error_code:        error to return to caller (if synchronous call)
+ */
+static void binder_cleanup_transaction(struct binder_transaction *t,
+                                      const char *reason,
+                                      uint32_t error_code)
+{
+       if (t->buffer->target_node && !(t->flags & TF_ONE_WAY)) {
+               binder_send_failed_reply(t, error_code);
+       } else {
+               binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
+                       "undelivered transaction %d, %s\n",
+                       t->debug_id, reason);
+               binder_free_transaction(t);
+       }
+}
+
 /**
  * binder_validate_object() - checks for a valid metadata object in a buffer.
  * @buffer:    binder_buffer that we're parsing.
@@ -4195,12 +4215,20 @@ retry:
                if (put_user(cmd, (uint32_t __user *)ptr)) {
                        if (t_from)
                                binder_thread_dec_tmpref(t_from);
+
+                       binder_cleanup_transaction(t, "put_user failed",
+                                                  BR_FAILED_REPLY);
+
                        return -EFAULT;
                }
                ptr += sizeof(uint32_t);
                if (copy_to_user(ptr, &tr, sizeof(tr))) {
                        if (t_from)
                                binder_thread_dec_tmpref(t_from);
+
+                       binder_cleanup_transaction(t, "copy_to_user failed",
+                                                  BR_FAILED_REPLY);
+
                        return -EFAULT;
                }
                ptr += sizeof(tr);
@@ -4270,15 +4298,9 @@ static void binder_release_work(struct binder_proc *proc,
                        struct binder_transaction *t;
 
                        t = container_of(w, struct binder_transaction, work);
-                       if (t->buffer->target_node &&
-                           !(t->flags & TF_ONE_WAY)) {
-                               binder_send_failed_reply(t, BR_DEAD_REPLY);
-                       } else {
-                               binder_debug(BINDER_DEBUG_DEAD_TRANSACTION,
-                                       "undelivered transaction %d\n",
-                                       t->debug_id);
-                               binder_free_transaction(t);
-                       }
+
+                       binder_cleanup_transaction(t, "process died.",
+                                                  BR_DEAD_REPLY);
                } break;
                case BINDER_WORK_RETURN_ERROR: {
                        struct binder_error *e = container_of(