From patchwork Thu Jun 27 20:19:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 1123606 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=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none 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.b="nQMs2Jud"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45ZWTc0KSnz9s4V for ; Fri, 28 Jun 2019 06:19:48 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726620AbfF0UTq (ORCPT ); Thu, 27 Jun 2019 16:19:46 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:11582 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726603AbfF0UTp (ORCPT ); Thu, 27 Jun 2019 16:19:45 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5RKHU1n018030 for ; Thu, 27 Jun 2019 13:19:44 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=TgShIAMH2M77hCq39IubGL3sFd/FdE/yllQPmhbxZKo=; b=nQMs2JudEbR0cycsMTS0iM3LCVavGKAOfn0bMQlpIyRWBldhfBa0C9E0chm9fNNjjTOb FseWebs5ZryTLW5ENAGCkuKv6/Yzg/08pBl7PPC9v4j+QtH1/u9ZaY6BhiiEgHFgCaeZ BY+jb6W0gC7cpRhhuR6oJBdjO4CjTF4c5Pk= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2td03ws8ur-10 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 27 Jun 2019 13:19:44 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Thu, 27 Jun 2019 13:19:40 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id F041462E2BE1; Thu, 27 Jun 2019 13:19:38 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: , CC: , , , , , , Song Liu Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v2 bpf-next 3/4] libbpf: add libbpf_[enable|disable]_sys_bpf() Date: Thu, 27 Jun 2019 13:19:22 -0700 Message-ID: <20190627201923.2589391-4-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190627201923.2589391-1-songliubraving@fb.com> References: <20190627201923.2589391-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-27_13:, , signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=961 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906270233 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This patch adds two more API to libbpf: libbpf_enable_sys_bpf() and libbpf_disable_sys_bpf(). For root, these two APIs are no-op. Signed-off-by: Song Liu --- tools/lib/bpf/libbpf.c | 54 ++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 7 ++++++ tools/lib/bpf/libbpf.map | 2 ++ 3 files changed, 63 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5186b7710430..449764840c5a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -4286,3 +4287,56 @@ int libbpf_num_possible_cpus(void) } return cpus; } + +LIBBPF_API bool libbpf_enable_sys_bpf(void) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int fd, ret; + + if (geteuid() == 0) + return true; + + fd = open(LIBBPF_DEV_BPF, O_WRONLY); + if (fd < 0) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to open %s: %s\n", LIBBPF_DEV_BPF, cp); + return false; + } + + ret = ioctl(fd, BPF_DEV_IOCTL_ENABLE_SYS_BPF); + + if (ret) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to enable access to sys_bpf(): %s\n", cp); + close(fd); + return false; + } + close(fd); + pr_debug("enabled access to sys_bpf() for non-privileged user\n"); + return true; +} + +LIBBPF_API void libbpf_disable_sys_bpf(void) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int fd, ret; + + if (geteuid() == 0) + return; + + fd = open(LIBBPF_DEV_BPF, O_WRONLY); + if (fd < 0) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to open %s: %s\n", LIBBPF_DEV_BPF, cp); + return; + } + + ret = ioctl(fd, BPF_DEV_IOCTL_DISABLE_SYS_BPF); + if (ret) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to disable access to sys_bpf(): %s\n", cp); + close(fd); + } + close(fd); + pr_debug("disabled access to sys_bpf() for non-privileged user\n"); +} diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d639f47e3110..0e3b9c0f1cdf 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -470,6 +470,13 @@ bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear); */ LIBBPF_API int libbpf_num_possible_cpus(void); +#define LIBBPF_DEV_BPF "/dev/bpf" + +/* (For non-root user) get permission to access bpf() syscall */ +LIBBPF_API bool libbpf_enable_sys_bpf(void); +/* (For non-root user) put permission to access bpf() syscall */ +LIBBPF_API void libbpf_disable_sys_bpf(void); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 2c6d835620d2..c5951315a3a5 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -173,4 +173,6 @@ LIBBPF_0.0.4 { btf__parse_elf; bpf_object__load_xattr; libbpf_num_possible_cpus; + libbpf_enable_sys_bpf; + libbpf_disable_sys_bpf; } LIBBPF_0.0.3;