From: Wei Yongjun <weiyongjun1@huawei.com>
To: <hulkci@huawei.com>, Eric Dumazet <eric.dumazet@gmail.com>,
Taehee Yoo <ap420073@gmail.com>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
"Hideaki YOSHIFUJI" <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>
Cc: Wei Yongjun <weiyongjun1@huawei.com>, <netdev@vger.kernel.org>
Subject: [PATCH] ip6_gre: fix null-ptr-deref in ip6gre_init_net()
Date: Mon, 13 Jul 2020 23:59:50 +0800 [thread overview]
Message-ID: <20200713155950.71793-1-weiyongjun1@huawei.com> (raw)
KASAN report null-ptr-deref error when register_netdev() failed:
KASAN: null-ptr-deref in range [0x00000000000003c0-0x00000000000003c7]
CPU: 2 PID: 422 Comm: ip Not tainted 5.8.0-rc4+ #12
Call Trace:
ip6gre_init_net+0x4ab/0x580
? ip6gre_tunnel_uninit+0x3f0/0x3f0
ops_init+0xa8/0x3c0
setup_net+0x2de/0x7e0
? rcu_read_lock_bh_held+0xb0/0xb0
? ops_init+0x3c0/0x3c0
? kasan_unpoison_shadow+0x33/0x40
? __kasan_kmalloc.constprop.0+0xc2/0xd0
copy_net_ns+0x27d/0x530
create_new_namespaces+0x382/0xa30
unshare_nsproxy_namespaces+0xa1/0x1d0
ksys_unshare+0x39c/0x780
? walk_process_tree+0x2a0/0x2a0
? trace_hardirqs_on+0x4a/0x1b0
? _raw_spin_unlock_irq+0x1f/0x30
? syscall_trace_enter+0x1a7/0x330
? do_syscall_64+0x1c/0xa0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x56/0xa0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
ip6gre_tunnel_uninit() has set 'ign->fb_tunnel_dev' to NULL, later
access to ign->fb_tunnel_dev cause null-ptr-deref. Fix it by saving
'ign->fb_tunnel_dev' to local variable ndev.
Fixes: dafabb6590cb ("ip6_gre: fix use-after-free in ip6gre_tunnel_lookup()")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 6532bde82b40..3a57fb9ce049 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1562,17 +1562,18 @@ static void ip6gre_destroy_tunnels(struct net *net, struct list_head *head)
static int __net_init ip6gre_init_net(struct net *net)
{
struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
+ struct net_device *ndev;
int err;
if (!net_has_fallback_tunnels(net))
return 0;
- ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6gre0",
- NET_NAME_UNKNOWN,
- ip6gre_tunnel_setup);
- if (!ign->fb_tunnel_dev) {
+ ndev = alloc_netdev(sizeof(struct ip6_tnl), "ip6gre0",
+ NET_NAME_UNKNOWN, ip6gre_tunnel_setup);
+ if (!ndev) {
err = -ENOMEM;
goto err_alloc_dev;
}
+ ign->fb_tunnel_dev = ndev;
dev_net_set(ign->fb_tunnel_dev, net);
/* FB netdevice is special: we have one, and only one per netns.
* Allowing to move it to another netns is clearly unsafe.
@@ -1592,7 +1593,7 @@ static int __net_init ip6gre_init_net(struct net *net)
return 0;
err_reg_dev:
- free_netdev(ign->fb_tunnel_dev);
+ free_netdev(ndev);
err_alloc_dev:
return err;
}
--
2.25.1
next reply other threads:[~2020-07-13 15:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 15:59 Wei Yongjun [this message]
2020-07-13 16:31 ` [PATCH] ip6_gre: fix null-ptr-deref in ip6gre_init_net() Eric Dumazet
2020-07-14 0:33 ` David Miller
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=20200713155950.71793-1-weiyongjun1@huawei.com \
--to=weiyongjun1@huawei.com \
--cc=ap420073@gmail.com \
--cc=eric.dumazet@gmail.com \
--cc=hulkci@huawei.com \
--cc=kuba@kernel.org \
--cc=kuznet@ms2.inr.ac.ru \
--cc=netdev@vger.kernel.org \
--cc=yoshfuji@linux-ipv6.org \
/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).