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Merge branch 'tipc-fix-two-race-issues-in-tipc_conn_alloc'

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Xin Long says:

====================
tipc: fix two race issues in tipc_conn_alloc

The race exists beteen tipc_topsrv_accept() and tipc_conn_close(),
one is allocating the con while the other is freeing it and there
is no proper lock protecting it. Therefore, a null-pointer-defer
and a use-after-free may be triggered, see details on each patch.
====================

Link: https://lore.kernel.org/r/cover.1668807842.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2022-11-21 20:45:28 -08:00
commit 3349c272de
1 changed files with 11 additions and 9 deletions
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20
net/tipc/topsrv.c
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@ -176,7 +176,7 @@ static void tipc_conn_close(struct tipc_conn *con)
conn_put(con);
}
static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s, struct socket *sock)
{
struct tipc_conn *con;
int ret;
@ -202,10 +202,12 @@ static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
}
con->conid = ret;
s->idr_in_use++;
spin_unlock_bh(&s->idr_lock);
set_bit(CF_CONNECTED, &con->flags);
con->server = s;
con->sock = sock;
conn_get(con);
spin_unlock_bh(&s->idr_lock);
return con;
}
@ -467,7 +469,7 @@ static void tipc_topsrv_accept(struct work_struct *work)
ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
if (ret < 0)
return;
con = tipc_conn_alloc(srv);
con = tipc_conn_alloc(srv, newsock);
if (IS_ERR(con)) {
ret = PTR_ERR(con);
sock_release(newsock);
@ -479,11 +481,11 @@ static void tipc_topsrv_accept(struct work_struct *work)
newsk->sk_data_ready = tipc_conn_data_ready;
newsk->sk_write_space = tipc_conn_write_space;
newsk->sk_user_data = con;
con->sock = newsock;
write_unlock_bh(&newsk->sk_callback_lock);
/* Wake up receive process in case of 'SYN+' message */
newsk->sk_data_ready(newsk);
conn_put(con);
}
}
@ -577,17 +579,17 @@ bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
sub.filter = filter;
*(u64 *)&sub.usr_handle = (u64)port;
con = tipc_conn_alloc(tipc_topsrv(net));
con = tipc_conn_alloc(tipc_topsrv(net), NULL);
if (IS_ERR(con))
return false;
*conid = con->conid;
con->sock = NULL;
rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
if (rc >= 0)
return true;
if (rc)
conn_put(con);
conn_put(con);
return false;
return !rc;
}
void tipc_topsrv_kern_unsubscr(struct net *net, int conid)