From patchwork Sun Nov 13 17:05:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hawkins Jiawei X-Patchwork-Id: 13041667 X-Patchwork-Delegate: kuba@kernel.org 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 375DBC4332F for ; Sun, 13 Nov 2022 17:05:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235144AbiKMRFY (ORCPT ); Sun, 13 Nov 2022 12:05:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232799AbiKMRFX (ORCPT ); Sun, 13 Nov 2022 12:05:23 -0500 Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com [IPv6:2607:f8b0:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 630E9DEE6; Sun, 13 Nov 2022 09:05:22 -0800 (PST) Received: by mail-pf1-x42c.google.com with SMTP id 140so7560344pfz.6; Sun, 13 Nov 2022 09:05:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=gA2/oZmfwkbn2XDHTL8FyR2xx1wlqu47HFzJm5YeRu8=; b=FrzKq3sBcmK7w6Lr9PwFG56hYyGXGffSTIj2Ql2D/MKxaBY8nj8NZJLjY9UaXriiIx 0l32NyLQBGptP9cgRHIMDael4OQRYPSeoEjVjaza7akvqdsA4lrcH97hlf3wLwiCnrWC lJNTv5AZx34ySde+Dz9TMpQQ/PoUdgpBb4l6IbQFrVA8/Gbr3EBuwbEPA/K87byw6sH+ ReFIpcy83XfwFDZXPe8TLKFtf0/Bnc1In8lWM6ed4985ArYSftD+LK2iyOz/IFCuFY3q kg+crTLR+M2L83c1fTp5JvcO/YhBwu+XBt0eTAjkDNmG2kyuDUAlSqq9rS870C0DUyFY DJsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=gA2/oZmfwkbn2XDHTL8FyR2xx1wlqu47HFzJm5YeRu8=; b=VMldAU1sq9t+9h0R6dWOAqy+06Mr1lgavjnjyU1AbVjAoBnL6hipx6QFqThd/ZUuR8 28jBdx9wzP1vQI68n57PuyNtoWfrc6wlY0QvlJl9maPu8xPULg/3KSkOBblIr81J2b+a bzdwuickIwTtns+1LKvr0NRiMUnf07pRxfKWqOIN/a0gjdt4GIisMIfJVwsqkYuJStsm AzNtFVDOQk7YvSLCPO3Ln08Xgbu5Mx/5UzR1CDldWRcHHpgmW5C46W++UDNg6yLpKPq9 ITvMef7H26+xW76O3FXStzaCK8GbTpopFhVuUSMNbHW2ZJCy8yS0iWlL3CDuHynvZTyV OrJw== X-Gm-Message-State: ANoB5pkUBkXd/L4VPV2wzDTtXHqFM2SD9mtBzkVPv4hwt6RLWE005wyg WuUf7xoexkb0TuOu7Hs4qM4= X-Google-Smtp-Source: AA0mqf5D99zy5/RvFZfaOGTNub+6Lugep+Fe3re3vYLt08FgSPu5U36c4ZT7799vqGP91WXn7NhIcQ== X-Received: by 2002:a05:6a00:1f13:b0:567:546c:718b with SMTP id be19-20020a056a001f1300b00567546c718bmr10846747pfb.17.1668359121826; Sun, 13 Nov 2022 09:05:21 -0800 (PST) Received: from localhost ([114.254.0.245]) by smtp.gmail.com with ESMTPSA id x66-20020a626345000000b0053e4296e1d3sm4938132pfb.198.2022.11.13.09.05.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Nov 2022 09:05:21 -0800 (PST) From: Hawkins Jiawei To: yin31149@gmail.com, Jamal Hadi Salim , Cong Wang , Jiri Pirko , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: 18801353760@163.com, syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, Cong Wang , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] net: sched: fix memory leak in tcindex_set_parms Date: Mon, 14 Nov 2022 01:05:08 +0800 Message-Id: <20221113170507.8205-1-yin31149@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Syzkaller reports a memory leak as follows: ==================================== BUG: memory leak unreferenced object 0xffff88810c287f00 (size 256): comm "syz-executor105", pid 3600, jiffies 4294943292 (age 12.990s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046 [] kmalloc include/linux/slab.h:576 [inline] [] kmalloc_array include/linux/slab.h:627 [inline] [] kcalloc include/linux/slab.h:659 [inline] [] tcf_exts_init include/net/pkt_cls.h:250 [inline] [] tcindex_set_parms+0xa7/0xbe0 net/sched/cls_tcindex.c:342 [] tcindex_change+0xdf/0x120 net/sched/cls_tcindex.c:553 [] tc_new_tfilter+0x4f2/0x1100 net/sched/cls_api.c:2147 [] rtnetlink_rcv_msg+0x4dc/0x5d0 net/core/rtnetlink.c:6082 [] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2540 [] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] [] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345 [] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921 [] sock_sendmsg_nosec net/socket.c:714 [inline] [] sock_sendmsg+0x56/0x80 net/socket.c:734 [] ____sys_sendmsg+0x178/0x410 net/socket.c:2482 [] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536 [] __sys_sendmmsg+0x105/0x330 net/socket.c:2622 [] __do_sys_sendmmsg net/socket.c:2651 [inline] [] __se_sys_sendmmsg net/socket.c:2648 [inline] [] __x64_sys_sendmmsg+0x24/0x30 net/socket.c:2648 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x63/0xcd ==================================== Kernel uses tcindex_change() to change an existing traffic-control-indices filter properties. During the process of changing, kernel clears the old traffic-control-indices filter result, and updates it by RCU assigning new traffic-control-indices data. Yet the problem is that, kernel clears the old traffic-control-indices filter result, without destroying its tcf_exts structure, which triggers the above memory leak. This patch solves it by using tcf_exts_destroy() to destroy the tcf_exts structure in old traffic-control-indices filter result, after the RCU grace period. [Thanks to the suggestion from Jakub Kicinski and Cong Wang] Fixes: b9a24bb76bf6 ("net_sched: properly handle failure case of tcf_exts_init()") Link: https://lore.kernel.org/all/0000000000001de5c505ebc9ec59@google.com/ Reported-by: syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com Tested-by: syzbot+232ebdbd36706c965ebf@syzkaller.appspotmail.com Cc: Cong Wang Cc: Jakub Kicinski Signed-off-by: Hawkins Jiawei --- v2: - remove all 'will' in commit message according to Jakub Kicinski - add Fixes tag according to Jakub Kicinski - remove all ifdefs according to Jakub Kicinski and Cong Wang - add synchronize_rcu() before destorying old_e according to Cong Wang v1: https://lore.kernel.org/all/20221031060835.11722-1-yin31149@gmail.com/ net/sched/cls_tcindex.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c index 1c9eeb98d826..d2fac9559d3e 100644 --- a/net/sched/cls_tcindex.c +++ b/net/sched/cls_tcindex.c @@ -338,6 +338,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base, struct tcf_result cr = {}; int err, balloc = 0; struct tcf_exts e; + struct tcf_exts old_e = {}; err = tcf_exts_init(&e, net, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE); if (err < 0) @@ -479,6 +480,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base, } if (old_r && old_r != r) { + old_e = old_r->exts; err = tcindex_filter_result_init(old_r, cp, net); if (err < 0) { kfree(f); @@ -510,6 +512,12 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base, tcf_exts_destroy(&new_filter_result.exts); } + /* Note: old_e should be destroyed after the RCU grace period, + * to avoid possible use-after-free by concurrent readers. + */ + synchronize_rcu(); + tcf_exts_destroy(&old_e); + if (oldp) tcf_queue_work(&oldp->rwork, tcindex_partial_destroy_work); return 0;