From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Rosenberg , Benjamin Tissoires , Jiri Kosina Subject: [PATCH 4.9 39/52] HID: debug: check length before copy_to_user() Date: Tue, 10 Jul 2018 20:25:07 +0200 Message-Id: <20180710182452.938266092@linuxfoundation.org> In-Reply-To: <20180710182449.285532226@linuxfoundation.org> References: <20180710182449.285532226@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Rosenberg commit 717adfdaf14704fd3ec7fa2c04520c0723247eac upstream. If our length is greater than the size of the buffer, we overflow the buffer Cc: stable@vger.kernel.org Signed-off-by: Daniel Rosenberg Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-debug.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -1152,6 +1152,8 @@ copy_rest: goto out; if (list->tail > list->head) { len = list->tail - list->head; + if (len > count) + len = count; if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) { ret = -EFAULT; @@ -1161,6 +1163,8 @@ copy_rest: list->head += len; } else { len = HID_DEBUG_BUFSIZE - list->head; + if (len > count) + len = count; if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) { ret = -EFAULT; @@ -1168,7 +1172,9 @@ copy_rest: } list->head = 0; ret += len; - goto copy_rest; + count -= len; + if (count > 0) + goto copy_rest; } }