netdev - [PATCH 1/2] net: sit: Unregister catch-all devices

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, 12 Apr 2021 20:41:16 +0300
From:   Hristo Venev <hristo@...ev.name>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, Hristo Venev <hristo@...ev.name>
Subject: [PATCH 1/2] net: sit: Unregister catch-all devices

A sit interface created without a local or a remote address is linked
into the `sit_net::tunnels_wc` list of its original namespace. When
deleting a network namespace, delete the devices that have been moved.

The following script triggers a null pointer dereference if devices
linked in a deleted `sit_net` remain:

    for i in `seq 1 30`; do
        ip netns add ns-test
        ip netns exec ns-test ip link add dev veth0 type veth peer veth1
        ip netns exec ns-test ip link add dev sit$i type sit dev veth0
        ip netns exec ns-test ip link set dev sit$i netns $$
        ip netns del ns-test
    done
    for i in `seq 1 30`; do
        ip link del dev sit$i
    done

Fixes: 5e6700b3bf98f ("sit: add support of x-netns")
Signed-off-by: Hristo Venev <hristo@...ev.name>
---
 net/ipv6/sit.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 63ccd9f2dccc..9fdccf0718b5 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1867,9 +1867,9 @@ static void __net_exit sit_destroy_tunnels(struct net *net,
 		if (dev->rtnl_link_ops == &sit_link_ops)
 			unregister_netdevice_queue(dev, head);
 
-	for (prio = 1; prio < 4; prio++) {
+	for (prio = 0; prio < 4; prio++) {
 		int h;
-		for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
+		for (h = 0; h < (prio ? IP6_SIT_HASH_SIZE : 1); h++) {
 			struct ip_tunnel *t;
 
 			t = rtnl_dereference(sitn->tunnels[prio][h]);
-- 
2.30.2