Date:   Tue, 30 Nov 2021 10:51:49 -0800
In-Reply-To: <20211130185152.437403-1-tkjos@google.com>
Message-Id: <20211130185152.437403-2-tkjos@google.com>
Mime-Version: 1.0
References: <20211130185152.437403-1-tkjos@google.com>
Subject: [PATCH v2 1/4] binder: fix handling of error during copy
From:   Todd Kjos <tkjos@google.com>
To:     tkjos@google.com, gregkh@linuxfoundation.org, christian@brauner.io,
        arve@android.com, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org, maco@google.com
Cc:     joel@joelfernandes.org, kernel-team@android.com, avakj45@gmail.com,
        Dan Carpenter <dan.carpenter@oracle.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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@oracle.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
---
v2: Added this patch to fix bug noticed by Dan Carpenter

 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 49fb74196d02..984e6263dcc7 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2269,8 +2269,8 @@ 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;
 }
-- 
2.34.0.rc2.393.gf8c9666880-goog