From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:50718 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731315AbeJKXQp (ORCPT ); Thu, 11 Oct 2018 19:16:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jon Maloy , Ying Xue , Cong Wang , "David S. Miller" Subject: [PATCH 4.18 40/44] tipc: call start and done ops directly in __tipc_nl_compat_dumpit() Date: Thu, 11 Oct 2018 17:40:18 +0200 Message-Id: <20181011152454.213513083@linuxfoundation.org> In-Reply-To: <20181011152452.571669983@linuxfoundation.org> References: <20181011152452.571669983@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cong Wang commit 8f5c5fcf353302374b36232d6885c1a3b579e5ca upstream. __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 Cc: Ying Xue Signed-off-by: Cong Wang Acked-by: Ying Xue Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/tipc/netlink_compat.c | 2 ++ net/tipc/socket.c | 17 +++++++++++------ net/tipc/socket.h | 1 + 3 files changed, 14 insertions(+), 6 deletions(-) --- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -185,6 +185,7 @@ static int __tipc_nl_compat_dumpit(struc 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(struc err = 0; err_out: + tipc_dump_done(&cb); kfree_skb(buf); if (err == -EMSGSIZE) { --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -3233,7 +3233,7 @@ int tipc_nl_sk_walk(struct sk_buff *skb, 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; @@ -3269,8 +3269,14 @@ 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) { @@ -3278,17 +3284,16 @@ int tipc_dump_start(struct netlink_callb 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); --- a/net/tipc/socket.h +++ b/net/tipc/socket.h @@ -69,5 +69,6 @@ int tipc_nl_sk_walk(struct sk_buff *skb, 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