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| author | Wei Yongjun <weiyongjun1@huawei.com> | 2020-07-13 18:59:50 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-31 19:47:14 +0300 |
| commit | 8480cda9d1d84c5ce18e2a93f9fedae1e63b7ff2 (patch) | |
| tree | 3a8f76b88e5b82d1415f6e4b8aeb7a201a173de3 | |
| parent | e729ee0b697b4e32ecb9153771aa33e13f0b8a0d (diff) | |
| download | linux-8480cda9d1d84c5ce18e2a93f9fedae1e63b7ff2.tar.xz | |
ip6_gre: fix null-ptr-deref in ip6gre_init_net()
[ Upstream commit 46ef5b89ec0ecf290d74c4aee844f063933c4da4 ]
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>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv6/ip6_gre.c | 11 |
1 files changed, 6 insertions, 5 deletions
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; } |