From 57497d1f0367e4418c7c5e419ba0f911ad840ce9 Mon Sep 17 00:00:00 2001
From: Daniel Wang <wonderfly@users.noreply.github.com>
Date: Wed, 24 May 2017 05:05:49 -0700
Subject: [PATCH] DHCP: Fail link_dhcp_set_routes promotely if no address is
 assigned from lease (#6009)

Currently the local variable `address` is unintialized if the DHCP lease
doesn't provide a router address (when r == -ENODATA). Thus the
subsequent call to route_scope_from_address will result in accessing an
unintialized variable.

As a matter of fact, sd-dhcp-client ignores DHCP leases without an
address so link_dhcp_set_routes probably will never be called without a
valid address.
(cherry picked from commit b23aec0d6b98bc99998786506a8769e1a1ea1841)
---
 src/network/networkd-dhcp4.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/network/networkd-dhcp4.c b/src/network/networkd-dhcp4.c
index ae0f78daab..9229b5753c 100644
--- a/src/network/networkd-dhcp4.c
+++ b/src/network/networkd-dhcp4.c
@@ -77,6 +77,10 @@ static int link_set_dhcp_routes(Link *link) {
         if (!link->network->dhcp_use_routes)
                 return 0;
 
+        r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
+        if (r < 0)
+                return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
+
         r = sd_dhcp_lease_get_router(link->dhcp_lease, &gateway);
         if (r < 0 && r != -ENODATA)
                 return log_link_warning_errno(link, r, "DHCP error: could not get gateway: %m");
@@ -85,10 +89,6 @@ static int link_set_dhcp_routes(Link *link) {
                 _cleanup_route_free_ Route *route = NULL;
                 _cleanup_route_free_ Route *route_gw = NULL;
 
-                r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
-                if (r < 0)
-                        return log_link_warning_errno(link, r, "DHCP error: could not get address: %m");
-
                 r = route_new(&route);
                 if (r < 0)
                         return log_link_error_errno(link, r, "Could not allocate route: %m");