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tipc: call start and done ops directly in __tipc_nl_compat_dumpit()

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__tipc_nl_compat_dumpit() uses a netlink_callback on stack,
so the only way to align it with other ->dumpit() call path
is calling tipc_dump_start() and tipc_dump_done() directly
inside it. Otherwise ->dumpit() would always get NULL from
cb->args[].

But tipc_dump_start() uses sock_net(cb->skb->sk) to retrieve
net pointer, the cb->skb here doesn't set skb->sk, the net pointer
is saved in msg->net instead, so introduce a helper function
__tipc_dump_start() to pass in msg->net.

Ying pointed out cb->args[0...3] are already used by other
callbacks on this call path, so we can't use cb->args[0] any
more, use cb->args[4] instead.

Fixes: 9a07efa9aea2 ("tipc: switch to rhashtable iterator")
Reported-and-tested-by: syzbot+e93a2c41f91b8e2c7d9b@syzkaller.appspotmail.com
Cc: Jon Maloy <jon.maloy@ericsson.com>
Cc: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Cong Wang 2018-09-04 14:54:55 -07:00 committed by David S. Miller
parent 6da410d97f
commit 8f5c5fcf35
3 changed files with 14 additions and 6 deletions
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2
net/tipc/netlink_compat.c
View File

@ -185,6 +185,7 @@ static int __tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
return -ENOMEM;
buf->sk = msg->dst_sk;
__tipc_dump_start(&cb, msg->net);
do {
int rem;
@ -216,6 +217,7 @@ static int __tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
err = 0;
err_out:
tipc_dump_done(&cb);
kfree_skb(buf);
if (err == -EMSGSIZE) {

17
net/tipc/socket.c
View File

@ -3230,7 +3230,7 @@ int tipc_nl_sk_walk(struct sk_buff *skb, struct netlink_callback *cb,
struct netlink_callback *cb,
struct tipc_sock *tsk))
{
struct rhashtable_iter *iter = (void *)cb->args[0];
struct rhashtable_iter *iter = (void *)cb->args[4];
struct tipc_sock *tsk;
int err;
@ -3266,8 +3266,14 @@ EXPORT_SYMBOL(tipc_nl_sk_walk);
int tipc_dump_start(struct netlink_callback *cb)
{
struct rhashtable_iter *iter = (void *)cb->args[0];
struct net *net = sock_net(cb->skb->sk);
return __tipc_dump_start(cb, sock_net(cb->skb->sk));
}
EXPORT_SYMBOL(tipc_dump_start);
int __tipc_dump_start(struct netlink_callback *cb, struct net *net)
{
/* tipc_nl_name_table_dump() uses cb->args[0...3]. */
struct rhashtable_iter *iter = (void *)cb->args[4];
struct tipc_net *tn = tipc_net(net);
if (!iter) {
@ -3275,17 +3281,16 @@ int tipc_dump_start(struct netlink_callback *cb)
if (!iter)
return -ENOMEM;
cb->args[0] = (long)iter;
cb->args[4] = (long)iter;
}
rhashtable_walk_enter(&tn->sk_rht, iter);
return 0;
}
EXPORT_SYMBOL(tipc_dump_start);
int tipc_dump_done(struct netlink_callback *cb)
{
struct rhashtable_iter *hti = (void *)cb->args[0];
struct rhashtable_iter *hti = (void *)cb->args[4];
rhashtable_walk_exit(hti);
kfree(hti);

1
net/tipc/socket.h
View File

@ -69,5 +69,6 @@ int tipc_nl_sk_walk(struct sk_buff *skb, struct netlink_callback *cb,
struct netlink_callback *cb,
struct tipc_sock *tsk));
int tipc_dump_start(struct netlink_callback *cb);
int __tipc_dump_start(struct netlink_callback *cb, struct net *net);
int tipc_dump_done(struct netlink_callback *cb);
#endif