From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADC6BC77B75 for ; Tue, 18 Apr 2023 12:33:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231612AbjDRMd1 (ORCPT ); Tue, 18 Apr 2023 08:33:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231593AbjDRMdZ (ORCPT ); Tue, 18 Apr 2023 08:33:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 783289EF8 for ; Tue, 18 Apr 2023 05:33:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5983A6318A for ; Tue, 18 Apr 2023 12:33:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 680A3C433D2; Tue, 18 Apr 2023 12:33:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681821182; bh=4RqeshYpMJdjCa4M9mwS8ZHGPMItg+lYT48K503qAho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=phDrN/A5rs51tB6elYFveWAjTuVry+wPKjBd1GOmkx4hK45rgYGG+6CnJH2+NLjql g+zg2GFXGCNhLnqa3SPCng5t2rt8tJWJi3Fx6SDggkGgPKpt7H3OJ7eei6BNuzCGwq BcxEgZZmq/lcBs2EPU0vLNNpETGZRr25udV7iBko= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+a7492efaa5d61b51db23@syzkaller.appspotmail.com, Ziyang Xuan , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 008/124] net: qrtr: Fix a refcount bug in qrtr_recvmsg() Date: Tue, 18 Apr 2023 14:20:27 +0200 Message-Id: <20230418120309.906414839@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230418120309.539243408@linuxfoundation.org> References: <20230418120309.539243408@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ziyang Xuan [ Upstream commit 44d807320000db0d0013372ad39b53e12d52f758 ] Syzbot reported a bug as following: refcount_t: addition on 0; use-after-free. ... RIP: 0010:refcount_warn_saturate+0x17c/0x1f0 lib/refcount.c:25 ... Call Trace: __refcount_add include/linux/refcount.h:199 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] qrtr_node_acquire net/qrtr/af_qrtr.c:202 [inline] qrtr_node_lookup net/qrtr/af_qrtr.c:398 [inline] qrtr_send_resume_tx net/qrtr/af_qrtr.c:1003 [inline] qrtr_recvmsg+0x85f/0x990 net/qrtr/af_qrtr.c:1070 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg+0xe2/0x160 net/socket.c:1038 qrtr_ns_worker+0x170/0x1700 net/qrtr/ns.c:688 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 It occurs in the concurrent scenario of qrtr_recvmsg() and qrtr_endpoint_unregister() as following: cpu0 cpu1 qrtr_recvmsg qrtr_endpoint_unregister qrtr_send_resume_tx qrtr_node_release qrtr_node_lookup mutex_lock(&qrtr_node_lock) spin_lock_irqsave(&qrtr_nodes_lock, ) refcount_dec_and_test(&node->ref) [node->ref == 0] radix_tree_lookup [node != NULL] __qrtr_node_release qrtr_node_acquire spin_lock_irqsave(&qrtr_nodes_lock, ) kref_get(&node->ref) [WARNING] ... mutex_unlock(&qrtr_node_lock) Use qrtr_node_lock to protect qrtr_node_lookup() implementation, this is actually improving the protection of node reference. Fixes: 0a7e0d0ef054 ("net: qrtr: Migrate node lookup tree to spinlock") Reported-by: syzbot+a7492efaa5d61b51db23@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=a7492efaa5d61b51db23 Signed-off-by: Ziyang Xuan Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/qrtr/af_qrtr.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c index 13448ca5aeff2..d0f0b2b8dce2f 100644 --- a/net/qrtr/af_qrtr.c +++ b/net/qrtr/af_qrtr.c @@ -388,10 +388,12 @@ static struct qrtr_node *qrtr_node_lookup(unsigned int nid) struct qrtr_node *node; unsigned long flags; + mutex_lock(&qrtr_node_lock); spin_lock_irqsave(&qrtr_nodes_lock, flags); node = radix_tree_lookup(&qrtr_nodes, nid); node = qrtr_node_acquire(node); spin_unlock_irqrestore(&qrtr_nodes_lock, flags); + mutex_unlock(&qrtr_node_lock); return node; } -- 2.39.2