From 99f1d3fc5043b33dea5faa88f7015a487965333f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Thu, 15 Feb 2018 09:37:44 +0100
Subject: [PATCH] sd-dhcp6: fix check if serverid is set

Ever since the initial implementation in 631bbe71298ec892f77f44f94feb612646fe6853,
client_parse_message() was supposed to check that the message contains exactly
one serverid. The check that no more than one is given was implemented
correctly, but the check that at least one is given was not. Simplify the whole
thing by making dhcp6_lease_get_serverid() return an error if the id is not
set, and do not require the arguments to be present if the contents of the id
are not needed.
---
 src/libsystemd-network/sd-dhcp6-client.c | 30 ++++++++++++------------
 src/libsystemd-network/sd-dhcp6-lease.c  | 11 +++++----
 2 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index 2d38e51424f..056bfa3d3d9 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -771,8 +771,6 @@ static int client_parse_message(
         size_t pos = 0;
         int r;
         bool clientid = false;
-        uint8_t *id = NULL;
-        size_t id_len;
         uint32_t lt_t1 = ~0, lt_t2 = ~0;
 
         assert(client);
@@ -817,8 +815,8 @@ static int client_parse_message(
                         break;
 
                 case SD_DHCP6_OPTION_SERVERID:
-                        r = dhcp6_lease_get_serverid(lease, &id, &id_len);
-                        if (r >= 0 && id) {
+                        r = dhcp6_lease_get_serverid(lease, NULL, NULL);
+                        if (r >= 0) {
                                 log_dhcp6_client(client, "%s contains multiple serverids",
                                                  dhcp6_message_type_to_string(message->type));
                                 return -EINVAL;
@@ -956,21 +954,23 @@ static int client_parse_message(
         }
 
         if (client->state != DHCP6_STATE_INFORMATION_REQUEST) {
-                r = dhcp6_lease_get_serverid(lease, &id, &id_len);
-                if (r < 0)
+                r = dhcp6_lease_get_serverid(lease, NULL, NULL);
+                if (r < 0) {
                         log_dhcp6_client(client, "%s has no server id",
                                          dhcp6_message_type_to_string(message->type));
-                return r;
-        }
+                        return -EINVAL;
+                }
 
-        if (lease->ia.addresses) {
-                lease->ia.ia_na.lifetime_t1 = htobe32(lt_t1);
-                lease->ia.ia_na.lifetime_t2 = htobe32(lt_t2);
-        }
+        } else {
+                if (lease->ia.addresses) {
+                        lease->ia.ia_na.lifetime_t1 = htobe32(lt_t1);
+                        lease->ia.ia_na.lifetime_t2 = htobe32(lt_t2);
+                }
 
-        if (lease->pd.addresses) {
-                lease->pd.ia_pd.lifetime_t1 = htobe32(lt_t1);
-                lease->pd.ia_pd.lifetime_t2 = htobe32(lt_t2);
+                if (lease->pd.addresses) {
+                        lease->pd.ia_pd.lifetime_t1 = htobe32(lt_t1);
+                        lease->pd.ia_pd.lifetime_t2 = htobe32(lt_t2);
+                }
         }
 
         return 0;
diff --git a/src/libsystemd-network/sd-dhcp6-lease.c b/src/libsystemd-network/sd-dhcp6-lease.c
index 1f3a782f8c0..0089fbb7370 100644
--- a/src/libsystemd-network/sd-dhcp6-lease.c
+++ b/src/libsystemd-network/sd-dhcp6-lease.c
@@ -95,11 +95,14 @@ int dhcp6_lease_set_serverid(sd_dhcp6_lease *lease, const uint8_t *id,
 
 int dhcp6_lease_get_serverid(sd_dhcp6_lease *lease, uint8_t **id, size_t *len) {
         assert_return(lease, -EINVAL);
-        assert_return(id, -EINVAL);
-        assert_return(len, -EINVAL);
 
-        *id = lease->serverid;
-        *len = lease->serverid_len;
+        if (!lease->serverid)
+                return -ENOMSG;
+
+        if (id)
+                *id = lease->serverid;
+        if (len)
+                *len = lease->serverid_len;
 
         return 0;
 }