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).

Signed-off-by: Martijn Coenen <maco@android.com>
Cc: stable <stable@vger.kernel.org> # 4.14
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 31 insertions, 9 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index a73596a4f804..bccec9de0533 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1948,6 +1948,26 @@ 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.
  * @offset:     offset in the buffer at which to validate an object.
@@ -4015,12 +4035,20 @@ 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);
@@ -4090,15 +4118,9 @@ 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(