Re: [PATCH] netlink: Safer deletion of sk_bind_node
From: Eric W. Biederman <hidden>
Date: 2014-09-02 01:13:11
Also in:
lkml
Harish Jenny K N writes:
From: Harish Jenny K N <redacted>
Unable to handle kernel NULL pointer dereference at virtual address 00000000
(netlink_release+0x0/0x2a0) from [<8034e78c>] (sock_release+0x28/0xa4)
(sock_release+0x0/0xa4) from [<8034e830>] (sock_close+0x28/0x34)
(sock_close+0x0/0x34) from [<800f3490>] (__fput+0xf0/0x1ec)
(__fput+0x0/0x1ec) from [<800f3634>] (____fput+0x10/0x14)
(____fput+0x0/0x14) from [<80040a64>] (task_work_run+0xb8/0xd8)
(task_work_run+0x0/0xd8) from [<800113a0>] (do_work_pending+0xb0/0xc4)
(do_work_pending+0x0/0xc4) from [<8000d960>] (work_pending+0xc/0x20)
Call flow of the inline and static functions
netlink_release
-----netlink_remove
---------__sk_del_bind_node
--------------__hlist_delIs there any reason __sk_del_bind_node should not be changed instead? If not there should be a description of what makes netlink's use of __sk_del_bind_node special.... Eric p.s. Your name was in your from line, but not your email address making it hard to reply to you.
quoted hunk
Signed-off-by: Harish Jenny K N <redacted> --- net/netlink/af_netlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index c416725..21a6b32 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c@@ -1103,7 +1103,7 @@ static void netlink_remove(struct sock *sk) netlink_table_grab(); if (nlk_sk(sk)->subscriptions) - __sk_del_bind_node(sk); + hlist_del_init(&sk->sk_bind_node); netlink_table_ungrab(); }@@ -1382,7 +1382,7 @@ netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions) struct netlink_sock *nlk = nlk_sk(sk); if (nlk->subscriptions && !subscriptions) - __sk_del_bind_node(sk); + hlist_del_init(&sk->sk_bind_node); else if (!nlk->subscriptions && subscriptions) sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list); nlk->subscriptions = subscriptions;