From: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
To: Steffen Klassert <steffen.klassert@secunet.com>,
"David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Haishuang Yan <yanhaishuang@cmss.chinamobile.com>,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH 1/2] ip_vti: fix a null pointer deferrence when create vti fallback tunnel
Date: Sun, 19 Aug 2018 15:05:04 +0800 [thread overview]
Message-ID: <1534662305-16734-1-git-send-email-yanhaishuang@cmss.chinamobile.com> (raw)
After set fb_tunnels_only_for_init_net to 1, the itn->fb_tunnel_dev will
be NULL and will cause following crash:
[ 2742.849298] BUG: unable to handle kernel NULL pointer dereference at 0000000000000941
[ 2742.851380] PGD 800000042c21a067 P4D 800000042c21a067 PUD 42aaed067 PMD 0
[ 2742.852818] Oops: 0002 [#1] SMP PTI
[ 2742.853570] CPU: 7 PID: 2484 Comm: unshare Kdump: loaded Not tainted 4.18.0-rc8+ #2
[ 2742.855163] Hardware name: Fedora Project OpenStack Nova, BIOS seabios-1.7.5-11.el7 04/01/2014
[ 2742.856970] RIP: 0010:vti_init_net+0x3a/0x50 [ip_vti]
[ 2742.858034] Code: 90 83 c0 48 c7 c2 20 a1 83 c0 48 89 fb e8 6e 3b f6 ff 85 c0 75 22 8b 0d f4 19 00 00 48 8b 93 00 14 00 00 48 8b 14 ca 48 8b 12 <c6> 82 41 09 00 00 04 c6 82 38 09 00 00 45 5b c3 66 0f 1f 44 00 00
[ 2742.861940] RSP: 0018:ffff9be28207fde0 EFLAGS: 00010246
[ 2742.863044] RAX: 0000000000000000 RBX: ffff8a71ebed4980 RCX: 0000000000000013
[ 2742.864540] RDX: 0000000000000000 RSI: 0000000000000013 RDI: ffff8a71ebed4980
[ 2742.866020] RBP: ffff8a71ea717000 R08: ffffffffc083903c R09: ffff8a71ea717000
[ 2742.867505] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a71ebed4980
[ 2742.868987] R13: 0000000000000013 R14: ffff8a71ea5b49c0 R15: 0000000000000000
[ 2742.870473] FS: 00007f02266c9740(0000) GS:ffff8a71ffdc0000(0000) knlGS:0000000000000000
[ 2742.872143] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2742.873340] CR2: 0000000000000941 CR3: 000000042bc20006 CR4: 00000000001606e0
[ 2742.874821] Call Trace:
[ 2742.875358] ops_init+0x38/0xf0
[ 2742.876078] setup_net+0xd9/0x1f0
[ 2742.876789] copy_net_ns+0xb7/0x130
[ 2742.877538] create_new_namespaces+0x11a/0x1d0
[ 2742.878525] unshare_nsproxy_namespaces+0x55/0xa0
[ 2742.879526] ksys_unshare+0x1a7/0x330
[ 2742.880313] __x64_sys_unshare+0xe/0x20
[ 2742.881131] do_syscall_64+0x5b/0x180
[ 2742.881933] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Reproduce:
echo 1 > /proc/sys/net/core/fb_tunnels_only_for_init_net
modprobe ip_vti
unshare -n
Fixes: 79134e6ce2c9 (net: do not create fallback tunnels for non-default
namespaces)
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
---
net/ipv4/ip_vti.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 3f091cc..f38cb21 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -438,7 +438,8 @@ static int __net_init vti_init_net(struct net *net)
if (err)
return err;
itn = net_generic(net, vti_net_id);
- vti_fb_tunnel_init(itn->fb_tunnel_dev);
+ if (itn->fb_tunnel_dev)
+ vti_fb_tunnel_init(itn->fb_tunnel_dev);
return 0;
}
--
1.8.3.1
next reply other threads:[~2018-08-19 7:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-19 7:05 Haishuang Yan [this message]
2018-08-19 7:05 ` [PATCH 2/2] ip6_vti: fix creating fallback tunnel device for vti6 Haishuang Yan
2018-08-19 18:27 ` David Miller
2018-08-19 18:27 ` [PATCH 1/2] ip_vti: fix a null pointer deferrence when create vti fallback tunnel David Miller
2018-08-20 1:58 ` Haishuang Yan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1534662305-16734-1-git-send-email-yanhaishuang@cmss.chinamobile.com \
--to=yanhaishuang@cmss.chinamobile.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=steffen.klassert@secunet.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).