9a07efa9ae
syzbot reported a use-after-free in tipc_group_fill_sock_diag(), where tipc_group_fill_sock_diag() still reads tsk->group meanwhile tipc_group_delete() just deletes it in tipc_release(). tipc_nl_sk_walk() aims to lock this sock when walking each sock in the hash table to close race conditions with sock changes like this one, by acquiring tsk->sk.sk_lock.slock spinlock, unfortunately this doesn't work at all. All non-BH call path should take lock_sock() instead to make it work. tipc_nl_sk_walk() brutally iterates with raw rht_for_each_entry_rcu() where RCU read lock is required, this is the reason why lock_sock() can't be taken on this path. This could be resolved by switching to rhashtable iterator API's, where taking a sleepable lock is possible. Also, the iterator API's are friendly for restartable calls like diag dump, the last position is remembered behind the scence, all we need to do here is saving the iterator into cb->args[]. I tested this with parallel tipc diag dump and thousands of tipc socket creation and release, no crash or memory leak. Reported-by: syzbot+b9c8f3ab2994b7cd1625@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> Signed-off-by: David S. Miller <davem@davemloft.net>
116 lines
3.5 KiB
C
116 lines
3.5 KiB
C
/*
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* net/tipc/diag.c: TIPC socket diag
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*
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* Copyright (c) 2018, Ericsson AB
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "ASIS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "socket.h"
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#include <linux/sock_diag.h>
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#include <linux/tipc_sockets_diag.h>
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static u64 __tipc_diag_gen_cookie(struct sock *sk)
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{
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u32 res[2];
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sock_diag_save_cookie(sk, res);
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return *((u64 *)res);
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}
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static int __tipc_add_sock_diag(struct sk_buff *skb,
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struct netlink_callback *cb,
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struct tipc_sock *tsk)
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{
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struct tipc_sock_diag_req *req = nlmsg_data(cb->nlh);
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struct nlmsghdr *nlh;
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int err;
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nlh = nlmsg_put_answer(skb, cb, SOCK_DIAG_BY_FAMILY, 0,
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NLM_F_MULTI);
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if (!nlh)
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return -EMSGSIZE;
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err = tipc_sk_fill_sock_diag(skb, cb, tsk, req->tidiag_states,
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__tipc_diag_gen_cookie);
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if (err)
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return err;
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nlmsg_end(skb, nlh);
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return 0;
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}
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static int tipc_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
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{
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return tipc_nl_sk_walk(skb, cb, __tipc_add_sock_diag);
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}
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static int tipc_sock_diag_handler_dump(struct sk_buff *skb,
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struct nlmsghdr *h)
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{
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int hdrlen = sizeof(struct tipc_sock_diag_req);
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struct net *net = sock_net(skb->sk);
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if (nlmsg_len(h) < hdrlen)
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return -EINVAL;
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if (h->nlmsg_flags & NLM_F_DUMP) {
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struct netlink_dump_control c = {
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.start = tipc_dump_start,
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.dump = tipc_diag_dump,
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.done = tipc_dump_done,
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};
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netlink_dump_start(net->diag_nlsk, skb, h, &c);
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return 0;
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}
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return -EOPNOTSUPP;
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}
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static const struct sock_diag_handler tipc_sock_diag_handler = {
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.family = AF_TIPC,
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.dump = tipc_sock_diag_handler_dump,
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};
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static int __init tipc_diag_init(void)
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{
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return sock_diag_register(&tipc_sock_diag_handler);
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}
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static void __exit tipc_diag_exit(void)
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{
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sock_diag_unregister(&tipc_sock_diag_handler);
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}
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module_init(tipc_diag_init);
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module_exit(tipc_diag_exit);
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MODULE_LICENSE("Dual BSD/GPL");
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MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, AF_TIPC);
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