netdev - [PATCH] ipv6: Fix finding best source address in ipv6_dev_get

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Mon, 13 Jul 2015 23:28:10 +0900
From:	YOSHIFUJI Hideaki/吉藤英明 
	<hideaki.yoshifuji@...aclelinux.com>
To:	davem@...emloft.net, netdev@...r.kernel.org
CC:	ek@...gle.com, thehajime@...il.com,
	YOSHIFUJI Hideaki/吉藤英明 
	<hideaki.yoshifuji@...aclelinux.com>
Subject: [PATCH] ipv6: Fix finding best source address in ipv6_dev_get_saddr().

Commit 9131f3de2 ("ipv6: Do not iterate over all interfaces when
finding source address on specific interface.") did not properly
update best source address available.  Plus, it introduced
possible NULL pointer dereference.

Bug was reported by Erik Kline <ek@...gle.com>.
Based on patch proposed by Hajime Tazaki <thehajime@...il.com>.

Fixes: 9131f3de24db4dc12199aede7d931e6703e97f3b ("ipv6: Do not
	iterate over all interfaces when finding source address
	on specific interface.")
Signed-off-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@...aclelinux.com>
---
 net/ipv6/addrconf.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 4ab74d5..4c9a024 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1358,14 +1358,15 @@ out:
 	return ret;
 }
 
-static void __ipv6_dev_get_saddr(struct net *net,
-				 struct ipv6_saddr_dst *dst,
-				 unsigned int prefs,
-				 const struct in6_addr *saddr,
-				 struct inet6_dev *idev,
-				 struct ipv6_saddr_score *scores)
+static int __ipv6_dev_get_saddr(struct net *net,
+				struct ipv6_saddr_dst *dst,
+				unsigned int prefs,
+				const struct in6_addr *saddr,
+				struct inet6_dev *idev,
+				struct ipv6_saddr_score *scores,
+				int hiscore_idx)
 {
-	struct ipv6_saddr_score *score = &scores[0], *hiscore = &scores[1];
+	struct ipv6_saddr_score *score = &scores[1 - hiscore_idx], *hiscore = &scores[hiscore_idx];
 
 	read_lock_bh(&idev->lock);
 	list_for_each_entry(score->ifa, &idev->addr_list, if_list) {
@@ -1424,6 +1425,7 @@ static void __ipv6_dev_get_saddr(struct net *net,
 				in6_ifa_hold(score->ifa);
 
 				swap(hiscore, score);
+				hiscore_idx = 1 - hiscore_idx;
 
 				/* restore our iterator */
 				score->ifa = hiscore->ifa;
@@ -1434,18 +1436,20 @@ static void __ipv6_dev_get_saddr(struct net *net,
 	}
 out:
 	read_unlock_bh(&idev->lock);
+	return hiscore_idx;
 }
 
 int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
 		       const struct in6_addr *daddr, unsigned int prefs,
 		       struct in6_addr *saddr)
 {
-	struct ipv6_saddr_score scores[2], *hiscore = &scores[1];
+	struct ipv6_saddr_score scores[2], *hiscore;
 	struct ipv6_saddr_dst dst;
 	struct inet6_dev *idev;
 	struct net_device *dev;
 	int dst_type;
 	bool use_oif_addr = false;
+	int hiscore_idx = 0;
 
 	dst_type = __ipv6_addr_type(daddr);
 	dst.addr = daddr;
@@ -1454,8 +1458,8 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
 	dst.label = ipv6_addr_label(net, daddr, dst_type, dst.ifindex);
 	dst.prefs = prefs;
 
-	hiscore->rule = -1;
-	hiscore->ifa = NULL;
+	scores[hiscore_idx].rule = -1;
+	scores[hiscore_idx].ifa = NULL;
 
 	rcu_read_lock();
 
@@ -1480,17 +1484,19 @@ int ipv6_dev_get_saddr(struct net *net, const struct net_device *dst_dev,
 	}
 
 	if (use_oif_addr) {
-		__ipv6_dev_get_saddr(net, &dst, prefs, saddr, idev, scores);
+		if (idev)
+			hiscore_idx = __ipv6_dev_get_saddr(net, &dst, prefs, saddr, idev, scores, hiscore_idx);
 	} else {
 		for_each_netdev_rcu(net, dev) {
 			idev = __in6_dev_get(dev);
 			if (!idev)
 				continue;
-			__ipv6_dev_get_saddr(net, &dst, prefs, saddr, idev, scores);
+			hiscore_idx = __ipv6_dev_get_saddr(net, &dst, prefs, saddr, idev, scores, hiscore_idx);
 		}
 	}
 	rcu_read_unlock();
 
+	hiscore = &scores[hiscore_idx];
 	if (!hiscore->ifa)
 		return -EADDRNOTAVAIL;
 
-- 
1.9.1

--
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