[PATCH 4.9 106/148] ipv6: reorder icmpv6_init() and ip6_mr_init()

Greg Kroah-Hartman
2017-12-12T13:12:43Z

From: WANG Cong <xiyou.wangcong@gmail.com>

[ Upstream commit 15e668070a64bb97f102ad9cf3bccbca0545cda8 ]

Andrey reported the following kernel crash:

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 14446 Comm: syz-executor6 Not tainted 4.10.0+ #82
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88001f311700 task.stack: ffff88001f6e8000
RIP: 0010:ip6mr_sk_done+0x15a/0x3d0 net/ipv6/ip6mr.c:1618
RSP: 0018:ffff88001f6ef418 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 1ffff10003edde8c RCX: ffffc900043ee000
RDX: 0000000000000004 RSI: ffffffff83e3b3f8 RDI: 0000000000000020
RBP: ffff88001f6ef508 R08: fffffbfff0dcc5d8 R09: 0000000000000000
R10: ffffffff86e62ec0 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88001f6ef4e0 R15: ffff8800380a0040
FS: 00007f7a52cec700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000061c500 CR3: 000000001f1ae000 CR4: 00000000000006f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
rawv6_close+0x4c/0x80 net/ipv6/raw.c:1217
inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432
sock_release+0x8d/0x1e0 net/socket.c:597
__sock_create+0x39d/0x880 net/socket.c:1226
sock_create_kern+0x3f/0x50 net/socket.c:1243
inet_ctl_sock_create+0xbb/0x280 net/ipv4/af_inet.c:1526
icmpv6_sk_init+0x163/0x500 net/ipv6/icmp.c:954
ops_init+0x10a/0x550 net/core/net_namespace.c:115
setup_net+0x261/0x660 net/core/net_namespace.c:291
copy_net_ns+0x27e/0x540 net/core/net_namespace.c:396
9pnet_virtio: no channels available for device ./file1
create_new_namespaces+0x437/0x9b0 kernel/nsproxy.c:106
unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:205
SYSC_unshare kernel/fork.c:2281 [inline]
SyS_unshare+0x64e/0x1000 kernel/fork.c:2231
entry_SYSCALL_64_fastpath+0x1f/0xc2

This is because net->ipv6.mr6_tables is not initialized at that point,
ip6mr_rules_init() is not called yet, therefore on the error path when
we iterator the list, we trigger this oops. Fix this by reordering
ip6mr_rules_init() before icmpv6_sk_init().

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/af_inet6.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -909,12 +909,12 @@ static int __init inet6_init(void)
err = register_pernet_subsys(&inet6_net_ops);
if (err)
goto register_pernet_fail;
- err = icmpv6_init();
- if (err)
- goto icmp_fail;
err = ip6_mr_init();
if (err)
goto ipmr_fail;
+ err = icmpv6_init();
+ if (err)
+ goto icmp_fail;
err = ndisc_init();
if (err)
goto ndisc_fail;
@@ -1044,10 +1044,10 @@ igmp_fail:
ndisc_cleanup();
ndisc_fail:
ip6_mr_cleanup();
-ipmr_fail:
- icmpv6_cleanup();
icmp_fail:
unregister_pernet_subsys(&inet6_net_ops);
+ipmr_fail:
+ icmpv6_cleanup();
register_pernet_fail:
sock_unregister(PF_INET6);
rtnl_unregister_all(PF_INET6);