From patchwork Wed Feb 15 11:54:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Jihong X-Patchwork-Id: 13141564 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 8A614C64ED8 for ; Wed, 15 Feb 2023 11:56:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231269AbjBOL4s (ORCPT ); Wed, 15 Feb 2023 06:56:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232544AbjBOL4q (ORCPT ); Wed, 15 Feb 2023 06:56:46 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D88628842; Wed, 15 Feb 2023 03:56:44 -0800 (PST) Received: from kwepemm600003.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4PGxPD6f26zrRvN; Wed, 15 Feb 2023 19:56:16 +0800 (CST) Received: from ubuntu1804.huawei.com (10.67.174.61) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Wed, 15 Feb 2023 19:56:40 +0800 From: Yang Jihong To: , , , , , , , , , , , , , CC: Subject: [PATCH 1/3] kprobes: Fixed probe nodes not correctly removed when forcibly unoptimized Date: Wed, 15 Feb 2023 19:54:28 +0800 Message-ID: <20230215115430.236046-2-yangjihong1@huawei.com> X-Mailer: git-send-email 2.30.GIT In-Reply-To: <20230215115430.236046-1-yangjihong1@huawei.com> References: <20230215115430.236046-1-yangjihong1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.174.61] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org When unoptimize_kprobe forcibly unoptimize the kprobe, simply queue it in the freeing_list, and do_free_cleaned_kprobes directly reclaims the kprobe if unoptimizing_list is empty (see do_unoptimize_kprobes), which may cause WARN or UAF problems. The specific scenarios are as follows: Thread1 arm_kprobe(p) mutex_lock(&kprobe_mutex) __arm_kprobe(kp) p = get_optimized_kprobe(p->addr) if (unlikely(_p)) unoptimize_kprobe(_p, true) // now _p is queued in freeing_list mutex_unlock(&kprobe_mutex) Thread2 kprobe_optimizer mutex_lock(&kprobe_mutex) do_unoptimize_kprobes if (list_empty(&unoptimizing_list)) return; // here directly returned and does not process freeing_list. ... do_free_cleaned_kprobes foreach op in freeing_list: WARN_ON_ONCE(!kprobe_unused(&op->kp)) // WANR will be triggered here. free_aggr_kprobe((&op->kp) // Delete op->kp directly, if access hash // list later, UAF problem will be triggered. mutex_unlock(&kprobe_mutex) The freeing_list needs to be processed in do_unoptimize_kprobes regardless of whether unoptimizing_list is empty. Signed-off-by: Yang Jihong --- kernel/kprobes.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 1c18ecf9f98b..0730e595f4c1 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -556,10 +556,9 @@ static void do_unoptimize_kprobes(void) lockdep_assert_cpus_held(); /* Unoptimization must be done anytime */ - if (list_empty(&unoptimizing_list)) - return; + if (!list_empty(&unoptimizing_list)) + arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); - arch_unoptimize_kprobes(&unoptimizing_list, &freeing_list); /* Loop on 'freeing_list' for disarming */ list_for_each_entry_safe(op, tmp, &freeing_list, list) { /* Switching from detour code to origin */