From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8317F1D90DB; Tue, 15 Oct 2024 11:35:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728992145; cv=none; b=cMKq004NhL9Fk/AHSNsgaDxbq8kRR+ZWQKkZPQaHf1RpBvKLlBc7afjnG+vfn4zloTxgSYglVVbQn7e7bwtQWzfXQ6BR4Xce+OcPNXteCbEgzw1lanWQ9cvZrWXPpPaY8xoOH1CuwN4nPUjys7xIrxoNibAuuFweuDqGIASZ5vw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728992145; c=relaxed/simple; bh=mdBg2YwBHx9FdUGTHM5K/tBElYmEoMU/lZobCS4L9JI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L6GyTHdGkJWZEh/DQCJmspU0BgCaNoMr6c6ou98aZheyjJ5RIdI6qrVN7oC5XQOK+Afg3KNWiuTkKxhmv7q1F2XxPziEclFx9iHuBkkE8sZDkyRK0b85mpQlzUyIgAWQ8S5CTDZwEuZtqTh0QU1JvtJEm3AMd1iu/ugc5MEjbJ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=p8NaAy0c; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="p8NaAy0c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2899C4CEC6; Tue, 15 Oct 2024 11:35:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728992145; bh=mdBg2YwBHx9FdUGTHM5K/tBElYmEoMU/lZobCS4L9JI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p8NaAy0caHLYrZbnMLsaTuX9EYGbSXd+lWtoAYLnCxezMrwTItpLMmuhZc+p3YQRF NNmJcrHi1sj/+aSQnpvJNFL/J9Bxh3wOCcD3Wjy71fER7vp9PQMit0qpj+LWbKAPLz X52NG6dkvTxyF43f5gWcmTIHAJTqFt7Il0ITdh4Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Matthieu Baerts (NGI0)" , Edward Adam Davis , Paolo Abeni , Jakub Kicinski , syzbot+f3a31fb909db9b2a5c4d@syzkaller.appspotmail.com Subject: [PATCH 5.15 031/691] mptcp: pm: Fix uaf in __timer_delete_sync Date: Tue, 15 Oct 2024 13:19:39 +0200 Message-ID: <20241015112441.573088747@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015112440.309539031@linuxfoundation.org> References: <20241015112440.309539031@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Edward Adam Davis 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: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Cc: stable@vger.kernel.org Reported-and-tested-by: syzbot+f3a31fb909db9b2a5c4d@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f3a31fb909db9b2a5c4d Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Edward Adam Davis Acked-by: Paolo Abeni Link: https://patch.msgid.link/tencent_7142963A37944B4A74EF76CD66EA3C253609@qq.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/pm_netlink.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -361,15 +361,21 @@ mptcp_pm_del_add_timer(struct mptcp_sock { 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; } @@ -1357,7 +1363,6 @@ static bool remove_anno_list_by_saddr(st entry = mptcp_pm_del_add_timer(msk, addr, false); if (entry) { - list_del(&entry->list); kfree(entry); return true; }