From 82dd97c4b73ace6067fbe3fa92a3c7eb5a95e89b Mon Sep 17 00:00:00 2001
From: Dan Williams <dcbw@redhat.com>
Date: Thu, 7 Oct 2010 00:29:44 -0500
Subject: [PATCH] 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.
---
 src/nm-policy-hosts.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 src/nm-policy.c       |  9 +++++++++
 2 files changed, 52 insertions(+)

diff --git a/src/nm-policy-hosts.c b/src/nm-policy-hosts.c
index 0403b03725..1b57d4275f 100644
--- a/src/nm-policy-hosts.c
+++ b/src/nm-policy-hosts.c
@@ -63,6 +63,21 @@ is_local_mapping (const char *str, gboolean ip6, const char *hostname)
 	        && nm_policy_hosts_find_token (str, hostname ? hostname : fallback));
 }
 
+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)
 {
@@ -85,6 +100,21 @@ ip4_addr_matches (const char *str, const char *ip4_addr)
 	return memcmp (&found, &given, sizeof (found)) == 0;
 }
 
+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)
 {
@@ -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 3ab4db550c..7382ece145 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);