commit 97de44c9a730fbb5a08d27e6899f7caffb015e66
Author: Dan Williams <dcbw@redhat.com>
Date:   Thu Oct 7 00:29:44 2010 -0500

    policy: ensure stale IP mappings are not left in /etc/hosts (bgo #629020) (rh #630146)
    
    NM-added mappings for active IP addresses were not getting properly
    removed when the address disappeared of NM quit, because the bits
    of code that determine whether or not /etc/hosts should change were
    not taking the disappearance of the IP address into account, and
    were leaving the file unchanged.
    
    To fix that, if there is no default IP address, but there are NM-added
    IP address entries in /etc/hosts, make sure we update /etc/hosts and
    remove them.

diff --git a/src/nm-policy-hosts.c b/src/nm-policy-hosts.c
index 0403b03..1b57d42 100644
--- a/src/nm-policy-hosts.c
+++ b/src/nm-policy-hosts.c
@@ -64,6 +64,21 @@ is_local_mapping (const char *str, gboolean ip6, const char *hostname)
 }
 
 static gboolean
+is_ip4_addr (const char *str)
+{
+	struct in_addr found;
+	char buf[INET_ADDRSTRLEN + 2];
+	const char *p = str;
+	guint32 i = 0;
+
+	memset (buf, 0, sizeof (buf));
+	while (*p && !isblank (*p) && (i < sizeof (buf)))
+		buf[i++] = *p++;
+
+	return inet_pton (AF_INET, buf, &found) == 1 ? TRUE : FALSE;
+}
+
+static gboolean
 ip4_addr_matches (const char *str, const char *ip4_addr)
 {
 	struct in_addr found, given;
@@ -86,6 +101,21 @@ ip4_addr_matches (const char *str, const char *ip4_addr)
 }
 
 static gboolean
+is_ip6_addr (const char *str)
+{
+	struct in6_addr found;
+	char buf[INET6_ADDRSTRLEN + 2];
+	const char *p = str;
+	guint32 i = 0;
+
+	memset (buf, 0, sizeof (buf));
+	while (*p && !isblank (*p) && (i < sizeof (buf)))
+		buf[i++] = *p++;
+
+	return inet_pton (AF_INET6, buf, &found) == 1 ? TRUE : FALSE;
+}
+
+static gboolean
 ip6_addr_matches (const char *str, const char *ip6_addr)
 {
 	struct in6_addr found, given;
@@ -176,7 +206,14 @@ nm_policy_get_etc_hosts (const char **lines,
 					found_user_host4 = TRUE;
 					host4_before = TRUE;  /* Ignore if user added mapping manually */
 				}
+			} else if (!ip4_addr && strstr (*line, ADDED_TAG)) {
+				/* If this is a stale NM-added IPv4 entry we need to remove it,
+				 * so make sure we update /etc/hosts.
+				 */
+				if (is_ip4_addr (*line))
+					found_host4 = FALSE;
 			}
+
 			if (ip6_addr && ip6_addr_matches (*line, ip6_addr)) {
 				found_host6 = TRUE;
 				if (strstr (*line, ADDED_TAG)) {
@@ -186,6 +223,12 @@ nm_policy_get_etc_hosts (const char **lines,
 					found_user_host6 = TRUE;
 					host6_before = TRUE;  /* Ignore if user added mapping manually */
 				}
+			} else if (!ip6_addr && strstr (*line, ADDED_TAG)) {
+				/* If this is a stale NM-added IPv6 entry we need to remove it,
+				 * so make sure we update /etc/hosts.
+				 */
+				if (is_ip6_addr (*line))
+					found_host6 = FALSE;
 			}
 		}
 
diff --git a/src/nm-policy.c b/src/nm-policy.c
index 3ab4db5..7382ece 100644
--- a/src/nm-policy.c
+++ b/src/nm-policy.c
@@ -1234,6 +1234,15 @@ nm_policy_destroy (NMPolicy *policy)
 	}
 	g_slist_free (policy->dev_signal_ids);
 
+	/* Rewrite /etc/hosts on exit to ensure we don't leave stale IP addresses
+	 * lying around.  FIXME: this will take out a valid IP address of an
+	 * ethernet device we're leaving active (ie, a connection we can "assume"
+	 * when NM starts again).
+	 */
+	policy->default_device4 = NULL;
+	policy->default_device6 = NULL;
+	update_system_hostname (policy, NULL, NULL);
+
 	g_free (policy->orig_hostname);
 	g_free (policy->cur_hostname);