From patchwork Mon Oct 24 11:27:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 10030 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:6687:0:0:0:0:0 with SMTP id l7csp622419wru; Mon, 24 Oct 2022 12:45:27 -0700 (PDT) X-Google-Smtp-Source: AMsMyM4OC0MG9nbum1RWS0Y/P80kZglFGL6GPdKc5DKYqGVUJk25KJsNo8W85OhVsIY3lEmR4ST3 X-Received: by 2002:a17:907:a422:b0:7a6:c4cb:dd42 with SMTP id sg34-20020a170907a42200b007a6c4cbdd42mr6952803ejc.735.1666640727693; Mon, 24 Oct 2022 12:45:27 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666640727; cv=none; d=google.com; s=arc-20160816; b=iHeEy9gQa8UIGaN0Dv1ldUC8bpCJW61SYUZtw67JXF3a28cTOfWRaehAzYPOeijme9 aPebmP31lOBXh6PfIgMMTqIC7VNIidB6k7iCye1WeMzOas/AJ8FT2J61OgfdTLbAHCIS iyF3JtCsMrzH+fNOt8kCuwBXvcwOAfjBpv7XkjoPUbP0ruA+AK4ViQLgYIeKe+kub7Qm UwjuSVaZ9/Mp9XUcuTMDF9vZxYgpfGUccdYnwixPKuc4mR7oYJL74HGbqBLmGYcXjMjj Iuc2tl6lOiOdeeEoa6bmUoAl7iX/Ggt5RdsemPig4g7KC/hJ3EgiitYC11LOGwrafRrS 9Hrg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=f0KatbyKqOhFgb8wkTVBL+h9RSdM8o6wciqTRv1Y9UQ=; b=G2hNVH8L1o8c95LBjoVFa3LqB7ujVde60aUT9izRrI9cUTh404dfUJK7LMSddeH7tY tMeI5+WZGnGN2BuaCv7VhsSJlBaSeuVqneJ/GSaAnSvtr/7b2tTbu3JV+uVMttLrKyec H5+irEuRhLZ9lP3Q+XdsgVxBe9QB37HAMDM+K91n3+1KKm+EHbN6Wln35wsaHS4aGQSO vSiJpHc6fT+fu75RqOeifslNzPaZRV4LzL37gkgd9vyV3RGoA1yzZutmjfSvXQJ/3NwV +J/v4PvJv/LySfe3diyvXGZAP1RiwsH5ZrZP220FNTv708mpjK5a/PoINX9qym+wbFKG jAVQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=tA6+7mPE; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id s27-20020a508d1b000000b0045a3b951e8bsi620374eds.194.2022.10.24.12.44.59; Mon, 24 Oct 2022 12:45:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=tA6+7mPE; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230315AbiJXTmP (ORCPT + 99 others); Mon, 24 Oct 2022 15:42:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232907AbiJXTlU (ORCPT ); Mon, 24 Oct 2022 15:41:20 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D1DE2871B; Mon, 24 Oct 2022 11:11:03 -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 ams.source.kernel.org (Postfix) with ESMTPS id C5114B818DF; Mon, 24 Oct 2022 12:38:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E085C433D6; Mon, 24 Oct 2022 12:38:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666615088; bh=D/B6aQwxRHmZZ3qRQKbdvIcJrvNDkoJUoMZvzwMn/Pc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tA6+7mPEyD4ryQUR6gEZ/xfpF+y+JXXYprdRIbPacSo9dm9nUYkvMXoNIeOmAfeBk jYyTRCJc7/dRS6mlj5+15Rv3IDgndXaqIOse30XtoPauuGlA7ajOphlXbIMorRM0WT /BwTydI9su1rGqALueAGiytk7+iouepAbbpgjb0s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrew Morton , Tom Zanussi , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" Subject: [PATCH 5.15 117/530] tracing: Fix reading strings from synthetic events Date: Mon, 24 Oct 2022 13:27:41 +0200 Message-Id: <20221024113050.335283491@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113044.976326639@linuxfoundation.org> References: <20221024113044.976326639@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747599467885253876?= X-GMAIL-MSGID: =?utf-8?q?1747599467885253876?= From: Steven Rostedt (Google) commit 0934ae9977c27133449b6dd8c6213970e7eece38 upstream. The follow commands caused a crash: # cd /sys/kernel/tracing # echo 's:open char file[]' > dynamic_events # echo 'hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)' > events/syscalls/sys_enter_openat/trigger' # echo 1 > events/synthetic/open/enable BOOM! The problem is that the synthetic event field "char file[]" will read the value given to it as a string without any memory checks to make sure the address is valid. The above example will pass in the user space address and the sythetic event code will happily call strlen() on it and then strscpy() where either one will cause an oops when accessing user space addresses. Use the helper functions from trace_kprobe and trace_eprobe that can read strings safely (and actually succeed when the address is from user space and the memory is mapped in). Now the above can show: packagekitd-1721 [000] ...2. 104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr in:imjournal-978 [006] ...2. 104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp packagekitd-1721 [000] ...2. 104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr Link: https://lkml.kernel.org/r/20221012104534.826549315@goodmis.org Cc: stable@vger.kernel.org Cc: Andrew Morton Cc: Tom Zanussi Acked-by: Masami Hiramatsu (Google) Reviewed-by: Tom Zanussi Fixes: bd82631d7ccdc ("tracing: Add support for dynamic strings to synthetic events") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_synth.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -17,6 +17,8 @@ /* for gfp flag names */ #include #include +#include "trace_probe.h" +#include "trace_probe_kernel.h" #include "trace_synth.h" @@ -401,6 +403,7 @@ static unsigned int trace_string(struct { unsigned int len = 0; char *str_field; + int ret; if (is_dynamic) { u32 data_offset; @@ -409,19 +412,27 @@ static unsigned int trace_string(struct data_offset += event->n_u64 * sizeof(u64); data_offset += data_size; - str_field = (char *)entry + data_offset; - - len = strlen(str_val) + 1; - strscpy(str_field, str_val, len); + len = kern_fetch_store_strlen((unsigned long)str_val); data_offset |= len << 16; *(u32 *)&entry->fields[*n_u64] = data_offset; + ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry); + (*n_u64)++; } else { str_field = (char *)&entry->fields[*n_u64]; - strscpy(str_field, str_val, STR_VAR_LEN_MAX); +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE + if ((unsigned long)str_val < TASK_SIZE) + ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX); + else +#endif + ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX); + + if (ret < 0) + strcpy(str_field, FAULT_STRING); + (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64); } @@ -454,7 +465,7 @@ static notrace void trace_event_raw_even val_idx = var_ref_idx[field_pos]; str_val = (char *)(long)var_ref_vals[val_idx]; - len = strlen(str_val) + 1; + len = kern_fetch_store_strlen((unsigned long)str_val); fields_size += len; }