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 X-Spam-Level: X-Spam-Status: No, score=-8.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 080A0C48BD5 for ; Tue, 25 Jun 2019 18:23:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8F5D2086D for ; Tue, 25 Jun 2019 18:23:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="BceKwcdl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732938AbfFYSXV (ORCPT ); Tue, 25 Jun 2019 14:23:21 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:24666 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732926AbfFYSXS (ORCPT ); Tue, 25 Jun 2019 14:23:18 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5PI4wwn003283 for ; Tue, 25 Jun 2019 11:23:17 -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=EbdI+tv3K3Ij6MyI3EN+D0t6s2Zu+exv/Pbe6ynvnic=; b=BceKwcdlORCMvjmuj+qKbyw8g9FRt/FCsgnGMWs1Q3fEuyPhtEu2ZWbfNP28lDNxvgoo v1u31tWIeNCxzZLDKnMchG0s6O3Ws0Y800sFFRVu7Irsx2BuV+rOaJ/1fsfoLaoDFKCB sBWK/V4PKyHqTmCJytWvwSPqhFAWGBGk560= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2tb3cmcmd5-5 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 25 Jun 2019 11:23:17 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 25 Jun 2019 11:23:14 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id A441F62E1DB8; Tue, 25 Jun 2019 11:23:13 -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 bpf-next 3/4] libbpf: add libbpf_[get|put]_bpf_permission() Date: Tue, 25 Jun 2019 11:23:02 -0700 Message-ID: <20190625182303.874270-4-songliubraving@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190625182303.874270-1-songliubraving@fb.com> References: <20190625182303.874270-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-25_12:,, 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906250137 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch adds two more API to libbpf: libbpf_get_bpf_permission() and libbpf_put_bpf_permission(). 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 68f45a96769f..cf2d68268bde 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_get_bpf_permission(void) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int fd, ret; + + if (geteuid() == 0) + return true; + + fd = open(LIBBPF_DEV_BPF, O_RDONLY); + 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_GET_PERM); + + if (ret) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to get BPF permission: %s\n", cp); + close(fd); + return false; + } + close(fd); + pr_debug("got BPF permission for non-privileged user\n"); + return true; +} + +LIBBPF_API void libbpf_put_bpf_permission(void) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int fd, ret; + + if (geteuid() == 0) + return; + + fd = open(LIBBPF_DEV_BPF, O_RDONLY); + 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_PUT_PERM); + if (ret) { + cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); + pr_warning("failed to release BPF permission: %s\n", cp); + close(fd); + } + close(fd); + pr_debug("released BPF permission for non-privileged user\n"); +} diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d639f47e3110..22052c55a96c 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_get_bpf_permission(void); +/* (For non-root user) put permission to access bpf() syscall */ +LIBBPF_API void libbpf_put_bpf_permission(void); + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 2c6d835620d2..93a2c4175fdd 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_get_bpf_permission; + libbpf_put_bpf_permission; } LIBBPF_0.0.3; -- 2.17.1