| From 7aaf54a1884f71dc363f0b884e57bcb67407a6cd Mon Sep 17 00:00:00 2001 |
| From: Matthieu Herrb <matthieu@herrb.eu> |
| Date: Sun, 21 Mar 2021 18:38:57 +0100 |
| Subject: [PATCH] Fix XChangeFeedbackControl() request underflow |
| |
| CVE-2021-3472 / ZDI-CAN-1259 |
| |
| This vulnerability was discovered by: |
| Jan-Niklas Sohn working with Trend Micro Zero Day Initiative |
| |
| Signed-off-by: Matthieu Herrb <matthieu@herrb.eu> |
| |
| Upstream-Status: Backport |
| CVE: CVE-2021-3472 |
| |
| Reference to upstream patch: |
| [https://gitlab.freedesktop.org/xorg/xserver/-/commit/7aaf54a1884f71dc363f0b884e57bcb67407a6cd] |
| |
| Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.com> |
| --- |
| Xi/chgfctl.c | 5 ++++- |
| 1 file changed, 4 insertions(+), 1 deletion(-) |
| |
| diff --git a/Xi/chgfctl.c b/Xi/chgfctl.c |
| index 1de4da9..7a597e4 100644 |
| --- a/Xi/chgfctl.c |
| +++ b/Xi/chgfctl.c |
| @@ -464,8 +464,11 @@ ProcXChangeFeedbackControl(ClientPtr client) |
| break; |
| case StringFeedbackClass: |
| { |
| - xStringFeedbackCtl *f = ((xStringFeedbackCtl *) &stuff[1]); |
| + xStringFeedbackCtl *f; |
| |
| + REQUEST_AT_LEAST_EXTRA_SIZE(xChangeFeedbackControlReq, |
| + sizeof(xStringFeedbackCtl)); |
| + f = ((xStringFeedbackCtl *) &stuff[1]); |
| if (client->swapped) { |
| if (len < bytes_to_int32(sizeof(xStringFeedbackCtl))) |
| return BadLength; |
| -- |
| 2.17.1 |
| |