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 E3F2CC433FE for ; Tue, 8 Nov 2022 14:38:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234179AbiKHOi4 (ORCPT ); Tue, 8 Nov 2022 09:38:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233896AbiKHOiv (ORCPT ); Tue, 8 Nov 2022 09:38:51 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEFB712AC8 for ; Tue, 8 Nov 2022 06:38:50 -0800 (PST) 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 59A6F615B2 for ; Tue, 8 Nov 2022 14:38:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4A6EC433C1; Tue, 8 Nov 2022 14:38:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667918329; bh=b06RHEoXPnJDhsGMEMR17ZoTZFIEJbYp2XZZpBaKs30=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Dg+vUj0wvoS76ihRQms745SlnPMub+4jKjvDl+1iiuw+Jf5CQTaYKSBkcA99YVJig QuCeUzI4YS2M90uQ9fsz313ZKykgSpTMWflUdZhDnzh6Rnx7EXXciuTiPWZpn7V9A3 6eYFvW8EikBF/N96vge2+MmDnRv/RVLEKtgVk9ka9vCVLnSYNRK/3RgiGDzndxw1Ie onqk6ah+gj2PcjZrwxQKyO6w1ok5oyNOBSthLL1nHjwkomGPKtDCj7uNNKY+EAcYna IogSxYUYOqXPRaKSMeQ8+6fhJy4AF9HoF/4q0KA07VYqN13abmprpkYHcD2PHSltTj PbgrGWS0AxgLQ== Date: Tue, 8 Nov 2022 23:38:46 +0900 From: Masami Hiramatsu (Google) To: Shang XiaoJing Cc: , , Subject: Re: [PATCH v2 2/2] tracing: kprobe: Fix potential null-ptr-deref on trace_array in kprobe_event_gen_test_exit() Message-Id: <20221108233846.fcff734a2f4b1a2a091fb831@kernel.org> In-Reply-To: <20221108015130.28326-3-shangxiaojing@huawei.com> References: <20221108015130.28326-1-shangxiaojing@huawei.com> <20221108015130.28326-3-shangxiaojing@huawei.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 8 Nov 2022 09:51:30 +0800 Shang XiaoJing wrote: > When test_gen_kprobe_cmd() failed after kprobe_event_gen_cmd_end(), it > will goto delete, which will call kprobe_event_delete() and release the > corresponding resource. However, the trace_array in gen_kretprobe_test > will point to the invalid resource. Set gen_kretprobe_test to NULL > after called kprobe_event_delete() to prevent null-ptr-deref. > > BUG: kernel NULL pointer dereference, address: 0000000000000070 > PGD 0 P4D 0 > Oops: 0000 [#1] SMP PTI > CPU: 0 PID: 246 Comm: modprobe Tainted: G W > 6.1.0-rc1-00174-g9522dc5c87da-dirty #248 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 > RIP: 0010:__ftrace_set_clr_event_nolock+0x53/0x1b0 > Code: e8 82 26 fc ff 49 8b 1e c7 44 24 0c ea ff ff ff 49 39 de 0f 84 3c > 01 00 00 c7 44 24 18 00 00 00 00 e8 61 26 fc ff 48 8b 6b 10 <44> 8b 65 > 70 4c 8b 6d 18 41 f7 c4 00 02 00 00 75 2f > RSP: 0018:ffffc9000159fe00 EFLAGS: 00010293 > RAX: 0000000000000000 RBX: ffff88810971d268 RCX: 0000000000000000 > RDX: ffff8881080be600 RSI: ffffffff811b48ff RDI: ffff88810971d058 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 > R10: ffffc9000159fe58 R11: 0000000000000001 R12: ffffffffa0001064 > R13: ffffffffa000106c R14: ffff88810971d238 R15: 0000000000000000 > FS: 00007f89eeff6540(0000) GS:ffff88813b600000(0000) > knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000070 CR3: 000000010599e004 CR4: 0000000000330ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > __ftrace_set_clr_event+0x3e/0x60 > trace_array_set_clr_event+0x35/0x50 > ? 0xffffffffa0000000 > kprobe_event_gen_test_exit+0xcd/0x10b [kprobe_event_gen_test] > __x64_sys_delete_module+0x206/0x380 > ? lockdep_hardirqs_on_prepare+0xd8/0x190 > ? syscall_enter_from_user_mode+0x1c/0x50 > do_syscall_64+0x3f/0x90 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > RIP: 0033:0x7f89eeb061b7 > > Fixes: 64836248dda2 ("tracing: Add kprobe event command generation test module") > Signed-off-by: Shang XiaoJing This looks good to me. Acked-by: Masami Hiramatsu (Google) Thank you! > Cc: stable@vger.kernel.org > --- > changes in v2: > - add cc tag to stable@vger.kernel.org. > - set gen_kprobe_test to NULL instead of gen_kprobe_test->tr, so as > gen_kretprobe_test. > --- > kernel/trace/kprobe_event_gen_test.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c > index 1c98fafcf333..c736487fc0e4 100644 > --- a/kernel/trace/kprobe_event_gen_test.c > +++ b/kernel/trace/kprobe_event_gen_test.c > @@ -143,6 +143,8 @@ static int __init test_gen_kprobe_cmd(void) > kfree(buf); > return ret; > delete: > + if (trace_event_file_is_valid(gen_kprobe_test)) > + gen_kprobe_test = NULL; > /* We got an error after creating the event, delete it */ > ret = kprobe_event_delete("gen_kprobe_test"); > goto out; > @@ -206,6 +208,8 @@ static int __init test_gen_kretprobe_cmd(void) > kfree(buf); > return ret; > delete: > + if (trace_event_file_is_valid(gen_kretprobe_test)) > + gen_kretprobe_test = NULL; > /* We got an error after creating the event, delete it */ > ret = kprobe_event_delete("gen_kretprobe_test"); > goto out; > -- > 2.17.1 > -- Masami Hiramatsu (Google)