diff options
author | Gong, Sishuai <sishuai@purdue.edu> | 2021-04-27 18:04:24 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2021-04-28 00:23:13 +0300 |
commit | 69e16d01d1de4f1249869de342915f608feb55d5 (patch) | |
tree | 07ad6e46ad91358a2043adcb7e522ad71408bcd7 /Documentation/process | |
parent | 6fd6c483e7abf0f67d02d9a49b217efcd01314f4 (diff) | |
download | linux-69e16d01d1de4f1249869de342915f608feb55d5.tar.xz |
net: fix a concurrency bug in l2tp_tunnel_register()
l2tp_tunnel_register() registers a tunnel without fully
initializing its attribute. This can allow another kernel thread
running l2tp_xmit_core() to access the uninitialized data and
then cause a kernel NULL pointer dereference error, as shown below.
Thread 1 Thread 2
//l2tp_tunnel_register()
list_add_rcu(&tunnel->list, &pn->l2tp_tunnel_list);
//pppol2tp_connect()
tunnel = l2tp_tunnel_get(sock_net(sk), info.tunnel_id);
// Fetch the new tunnel
...
//l2tp_xmit_core()
struct sock *sk = tunnel->sock;
...
bh_lock_sock(sk);
//Null pointer error happens
tunnel->sock = sk;
Fix this bug by initializing tunnel->sock before adding the
tunnel into l2tp_tunnel_list.
Reviewed-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Sishuai Gong <sishuai@purdue.edu>
Reported-by: Sishuai Gong <sishuai@purdue.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/process')
0 files changed, 0 insertions, 0 deletions