From c232bc1f346a6af9777c216d01f7940898ae1650 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)

Resolves: #1643363

---

 src/libsystemd-network/dhcp6-option.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libsystemd-network/dhcp6-option.c b/src/libsystemd-network/dhcp6-option.c

index 18196b1257..0979497299 100644

--- a/src/libsystemd-network/dhcp6-option.c

+++ b/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;