Commit 1bc18174 authored by Edward Adam Davis's avatar Edward Adam Davis Committed by Wang Liang
Browse files

mptcp: pm: Fix uaf in __timer_delete_sync 

stable inclusion
from stable-v6.6.52
commit 6452b162549c7f9ef54655d3fb9977b9192e6e5b
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAU9JW
CVE: CVE-2024-46858

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6452b162549c7f9ef54655d3fb9977b9192e6e5b



--------------------------------

commit b4cd80b0338945a94972ac3ed54f8338d2da2076 upstream.

There are two paths to access mptcp_pm_del_add_timer, result in a race
condition:

     CPU1				CPU2
     ====                               ====
     net_rx_action
     napi_poll                          netlink_sendmsg
     __napi_poll                        netlink_unicast
     process_backlog                    netlink_unicast_kernel
     __netif_receive_skb                genl_rcv
     __netif_receive_skb_one_core       netlink_rcv_skb
     NF_HOOK                            genl_rcv_msg
     ip_local_deliver_finish            genl_family_rcv_msg
     ip_protocol_deliver_rcu            genl_family_rcv_msg_doit
     tcp_v4_rcv                         mptcp_pm_nl_flush_addrs_doit
     tcp_v4_do_rcv                      mptcp_nl_remove_addrs_list
     tcp_rcv_established                mptcp_pm_remove_addrs_and_subflows
     tcp_data_queue                     remove_anno_list_by_saddr
     mptcp_incoming_options             mptcp_pm_del_add_timer
     mptcp_pm_del_add_timer             kfree(entry)

In remove_anno_list_by_saddr(running on CPU2), after leaving the critical
zone protected by "pm.lock", the entry will be released, which leads to the
occurrence of uaf in the mptcp_pm_del_add_timer(running on CPU1).

Keeping a reference to add_timer inside the lock, and calling
sk_stop_timer_sync() with this reference, instead of "entry->add_timer".

Move list_del(&entry->list) to mptcp_pm_del_add_timer and inside the pm lock,
do not directly access any members of the entry outside the pm lock, which
can avoid similar "entry->x" uaf.

Fixes: 00cfd77b ("mptcp: retransmit ADD_ADDR when timeout")
Cc: stable@vger.kernel.org
Reported-and-tested-by: default avatar <syzbot+f3a31fb909db9b2a5c4d@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=f3a31fb909db9b2a5c4d


Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: default avatarEdward Adam Davis <eadavis@qq.com>
Acked-by: default avatarPaolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/tencent_7142963A37944B4A74EF76CD66EA3C253609@qq.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWang Liang <wangliang74@huawei.com>
parent e4bfde20

net/mptcp/pm_netlink.c

+9 −4
Original line number Diff line number Diff line
@@ -336,15 +336,21 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk, 
{

	struct mptcp_pm_add_entry *entry;

	struct sock *sk = (struct sock *)msk;

	struct timer_list *add_timer = NULL;



	spin_lock_bh(&msk->pm.lock);

	entry = mptcp_lookup_anno_list_by_saddr(msk, addr);

	if (entry && (!check_id || entry->addr.id == addr->id))

	if (entry && (!check_id || entry->addr.id == addr->id)) {

		entry->retrans_times = ADD_ADDR_RETRANS_MAX;

		add_timer = &entry->add_timer;

	}

	if (!check_id && entry)

		list_del(&entry->list);

	spin_unlock_bh(&msk->pm.lock);



	if (entry && (!check_id || entry->addr.id == addr->id))

		sk_stop_timer_sync(sk, &entry->add_timer);

	/* no lock, because sk_stop_timer_sync() is calling del_timer_sync() */

	if (add_timer)

		sk_stop_timer_sync(sk, add_timer);



	return entry;

}
@@ -1405,7 +1411,6 @@ static bool remove_anno_list_by_saddr(struct mptcp_sock *msk, 


	entry = mptcp_pm_del_add_timer(msk, addr, false);

	if (entry) {

		list_del(&entry->list);

		kfree(entry);

		return true;

	}