From f4f765534191ed3c5d8e78b97333f3fd978a2b63 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 19 Oct 2018 12:12:33 +0200
Subject: [PATCH] dhcp6: make sure we have enough space for the DHCP6 option
 header

Fixes a vulnerability originally discovered by Felix Wilhelm from
Google.

CVE-2018-15688
LP: #1795921
https://bugzilla.redhat.com/show_bug.cgi?id=1639067

(cherry picked from commit 4dac5eaba4e419b29c97da38a8b1f82336c2c892)
(cherry picked from commit 01ca2053bbea09f35b958c8cc7631e15469acb79)
(cherry picked from commit fc230dca139142f409d7bac99dbfabe9b004e2fb)
(cherry picked from commit cc1e5a7f5731f223d1eb8473fa0eecbedfc0ae5f)
(cherry picked from commit c3221cb0c5b4a2936c198e33b6f7853141991277)
---
 src/systemd/src/libsystemd-network/dhcp6-option.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/systemd/src/libsystemd-network/dhcp6-option.c b/src/systemd/src/libsystemd-network/dhcp6-option.c
index d496244370..7615cb80e0 100644
--- a/src/systemd/src/libsystemd-network/dhcp6-option.c
+++ b/src/systemd/src/libsystemd-network/dhcp6-option.c
@@ -103,7 +103,7 @@ int dhcp6_option_append_ia(uint8_t **buf, size_t *buflen, DHCP6IA *ia) {
                 return -EINVAL;
         }
 
-        if (*buflen < len)
+        if (*buflen < offsetof(DHCP6Option, data) + len)
                 return -ENOBUFS;
 
         ia_hdr = *buf;