From patchwork Fri Apr 24 05:20:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1276146 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.a=rsa-sha256 header.s=facebook header.b=bkbdsMW9; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 497jF52H7hz9sSG for ; Fri, 24 Apr 2020 15:20:57 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726072AbgDXFU4 (ORCPT ); Fri, 24 Apr 2020 01:20:56 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:56154 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725919AbgDXFUz (ORCPT ); Fri, 24 Apr 2020 01:20:55 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 03O5JP79012432 for ; Thu, 23 Apr 2020 22:20:54 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=ikO0forPp7t8DcwlBPkaLeVSS6Obv2yCRfcHPNoff/0=; b=bkbdsMW976Io1VNZbrbtb+Bnde5m9xVokqOxSpzlZAHFu4kJSx4H8bZq26j6LyYuqnUt tUKddeio/KbiguOZls6WP9m/i4+41mEiMITcZ0y/lJdLbhc+bMLZPEFJt/D0kLOKI4Sb tkuRw95y7ULsIdzElEK+urWvSZPQp2y0ZGQ= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 30jq4jkxdx-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 23 Apr 2020 22:20:54 -0700 Received: from intmgw004.08.frc2.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Thu, 23 Apr 2020 22:20:53 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id AB0B12EC37B0; Thu, 23 Apr 2020 22:20:46 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v2 bpf] bpf: fix leak in LINK_UPDATE and enforce empty old_prog_fd Date: Thu, 23 Apr 2020 22:20:44 -0700 Message-ID: <20200424052045.4002963-1-andriin@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.676 definitions=2020-04-24_01:2020-04-23,2020-04-24 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=842 malwarescore=0 priorityscore=1501 bulkscore=0 phishscore=0 mlxscore=0 lowpriorityscore=0 adultscore=0 suspectscore=8 spamscore=0 clxscore=1015 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004240038 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Fix bug of not putting bpf_link in LINK_UPDATE command. Also enforce zeroed old_prog_fd if no BPF_F_REPLACE flag is specified. Signed-off-by: Andrii Nakryiko --- This version will merge with no conflicts with the upcoming LINK_UPDATE refactoring patch (part of bpf_link observability patch set). kernel/bpf/syscall.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index d85f37239540..bca58c235ac0 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3628,8 +3628,10 @@ static int link_update(union bpf_attr *attr) return PTR_ERR(link); new_prog = bpf_prog_get(attr->link_update.new_prog_fd); - if (IS_ERR(new_prog)) - return PTR_ERR(new_prog); + if (IS_ERR(new_prog)) { + ret = PTR_ERR(new_prog); + goto out_put_link; + } if (flags & BPF_F_REPLACE) { old_prog = bpf_prog_get(attr->link_update.old_prog_fd); @@ -3638,6 +3640,9 @@ static int link_update(union bpf_attr *attr) old_prog = NULL; goto out_put_progs; } + } else if (attr->link_update.old_prog_fd) { + ret = -EINVAL; + goto out_put_progs; } #ifdef CONFIG_CGROUP_BPF @@ -3653,6 +3658,8 @@ static int link_update(union bpf_attr *attr) bpf_prog_put(old_prog); if (ret) bpf_prog_put(new_prog); +out_put_link: + bpf_link_put(link); return ret; }