netdev - [PATCH] ipv6: Reparent temporary address(es) if global address was deleted from userspace

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 06 Apr 2014 21:04:11 +0200
From:	Heiner Kallweit <heiner.kallweit@....de>
To:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH] ipv6: Reparent temporary address(es) if global address was
 deleted from userspace

If the kernel takes care of global and temporary addresses it can happen that the global
address is deleted from userspace, e.g. by network managers in case the link goes (temporarily) down.
In addition to the then orphaned temporary address(es) the next RA will create a new temporary address.
Therefore we might end up with more than one non-deprecated temporary address for the same prefix
for a longer period of time (>regen_advance). According to RfC 4941 sect. 3.4 this should not happen.

Fix this by reparenting orphaned temporary addresses.

Signed-off-by: Heiner Kallweit <heiner.kallweit@....de>
---
 net/ipv6/addrconf.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6c7fa08..4d5595b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2077,14 +2077,34 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 {
 	u32 flags;
 	struct inet6_ifaddr *ift;
+	unsigned long regen_advance;
 
 	read_lock_bh(&idev->lock);
+	regen_advance = idev->cnf.regen_max_retry *
+			idev->cnf.dad_transmits *
+			NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ;
 	/* update all temporary addresses in the list */
 	list_for_each_entry(ift, &idev->tempaddr_list, tmp_list) {
 		int age, max_valid, max_prefered;
+		bool reparent;
 
-		if (ifp != ift->ifpub)
-			continue;
+		reparent = false;
+		spin_lock(&ift->lock);
+		if (ifp != ift->ifpub) {
+			/* reparent if orphaned temporary address with same
+			 * prefix is found
+			 */
+			if (ipv6_prefix_equal(&ift->addr, &ifp->addr,
+					      ift->prefix_len)) {
+				in6_ifa_hold(ifp);
+				in6_ifa_put(ift->ifpub);
+				ift->ifpub = ifp;
+				reparent = true;
+			} else {
+				spin_unlock(&ift->lock);
+				continue;
+			}
+		}
 
 		/* RFC 4941 section 3.3:
 		 * If a received option will extend the lifetime of a public
@@ -2110,7 +2130,6 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 		if (prefered_lft > max_prefered)
 			prefered_lft = max_prefered;
 
-		spin_lock(&ift->lock);
 		flags = ift->flags;
 		ift->valid_lft = valid_lft;
 		ift->prefered_lft = prefered_lft;
@@ -2119,6 +2138,15 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 			ift->flags &= ~IFA_F_DEPRECATED;
 
 		spin_unlock(&ift->lock);
+		/* Don't create a temporary address if we reparented one which
+		 * is prefered more than regen_advance
+		 */
+		if (reparent && prefered_lft > regen_advance) {
+			create = false;
+			pr_info("%s: reparent orphaned temporary address\n",
+				__func__);
+		}
+
 		if (!(flags&IFA_F_TENTATIVE))
 			ipv6_ifa_notify(0, ift);
 	}
-- 
1.9.1.315.g3f09db0.dirty

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html