From: Xin Long Date: Fri, 15 Sep 2017 07:58:33 +0000 (+0800) Subject: ip6_tunnel: do not allow loading ip6_tunnel if ipv6 is disabled in cmdline X-Git-Tag: v4.14-rc2~10^2~42 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8c22dab03ad072e45060c299c70d02a4f6fc4aab;p=platform%2Fkernel%2Flinux-rpi3.git ip6_tunnel: do not allow loading ip6_tunnel if ipv6 is disabled in cmdline If ipv6 has been disabled from cmdline since kernel started, it makes no sense to allow users to create any ip6 tunnel. Otherwise, it could some potential problem. Jianlin found a kernel crash caused by this in ip6_gre when he set ipv6.disable=1 in grub: [ 209.588865] Unable to handle kernel paging request for data at address 0x00000080 [ 209.588872] Faulting instruction address: 0xc000000000a3aa6c [ 209.588879] Oops: Kernel access of bad area, sig: 11 [#1] [ 209.589062] NIP [c000000000a3aa6c] fib_rules_lookup+0x4c/0x260 [ 209.589071] LR [c000000000b9ad90] fib6_rule_lookup+0x50/0xb0 [ 209.589076] Call Trace: [ 209.589097] fib6_rule_lookup+0x50/0xb0 [ 209.589106] rt6_lookup+0xc4/0x110 [ 209.589116] ip6gre_tnl_link_config+0x214/0x2f0 [ip6_gre] [ 209.589125] ip6gre_newlink+0x138/0x3a0 [ip6_gre] [ 209.589134] rtnl_newlink+0x798/0xb80 [ 209.589142] rtnetlink_rcv_msg+0xec/0x390 [ 209.589151] netlink_rcv_skb+0x138/0x150 [ 209.589159] rtnetlink_rcv+0x48/0x70 [ 209.589169] netlink_unicast+0x538/0x640 [ 209.589175] netlink_sendmsg+0x40c/0x480 [ 209.589184] ___sys_sendmsg+0x384/0x4e0 [ 209.589194] SyS_sendmsg+0xd4/0x140 [ 209.589201] SyS_socketcall+0x3e0/0x4f0 [ 209.589209] system_call+0x38/0xe0 This patch is to return -EOPNOTSUPP in ip6_tunnel_init if ipv6 has been disabled from cmdline. Reported-by: Jianlin Shi Signed-off-by: Xin Long Signed-off-by: David S. Miller --- diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index ae73164..f2f21c2 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -2259,6 +2259,9 @@ static int __init ip6_tunnel_init(void) { int err; + if (!ipv6_mod_enabled()) + return -EOPNOTSUPP; + err = register_pernet_device(&ip6_tnl_net_ops); if (err < 0) goto out_pernet;