[PATCH 5.10 260/563] binder: fix handling of error during copy

[Greg Kroah-Hartman]

From: Todd Kjos <tkjos@xxxxxxxxxx>

[ Upstream commit fe6b1869243f23a485a106c214bcfdc7aa0ed593 ]

If a memory copy function fails to copy the whole buffer,
a positive integar with the remaining bytes is returned.
In binder_translate_fd_array() this can result in an fd being
skipped due to the failed copy, but the loop continues
processing fds since the early return condition expects a
negative integer on error.

Fix by returning "ret > 0 ? -EINVAL : ret" to handle this case.

Fixes: bb4a2e48d510 ("binder: return errors from buffer copy functions")
Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
Signed-off-by: Todd Kjos <tkjos@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211130185152.437403-2-tkjos@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/android/binder.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 80e2bbb36422e..366b124057081 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2657,8 +2657,8 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
 		if (!ret)
 			ret = binder_translate_fd(fd, offset, t, thread,
 						  in_reply_to);
-		if (ret < 0)
-			return ret;
+		if (ret)
+			return ret > 0 ? -EINVAL : ret;
 	}
 	return 0;
 }
-- 
2.34.1