From patchwork Mon Nov 9 21:00:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 11892489 X-Patchwork-Delegate: bpf@iogearbox.net 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=-13.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 CFC0BC55ABD for ; Mon, 9 Nov 2020 21:03:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9475E206ED for ; Mon, 9 Nov 2020 21:03:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730493AbgKIVDm convert rfc822-to-8bit (ORCPT ); Mon, 9 Nov 2020 16:03:42 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:53058 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730480AbgKIVDl (ORCPT ); Mon, 9 Nov 2020 16:03:41 -0500 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.42/8.16.0.42) with SMTP id 0A9KlHiL015698 for ; Mon, 9 Nov 2020 13:03:40 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by m0001303.ppops.net with ESMTP id 34nr4pswah-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 09 Nov 2020 13:03:39 -0800 Received: from intmgw004.08.frc2.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Mon, 9 Nov 2020 13:03:38 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 2F11D2EC924D; Mon, 9 Nov 2020 13:00:30 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , , , , Andrii Nakryiko , Arnaldo Carvalho de Melo , Greg Kroah-Hartman Subject: [PATCH v3 bpf-next 2/5] bpf: assign ID to vmlinux BTF and return extra info for BTF in GET_OBJ_INFO Date: Mon, 9 Nov 2020 13:00:21 -0800 Message-ID: <20201109210024.2024572-3-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201109210024.2024572-1-andrii@kernel.org> References: <20201109210024.2024572-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-09_13:2020-11-05,2020-11-09 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 malwarescore=0 mlxlogscore=697 spamscore=0 suspectscore=75 mlxscore=0 bulkscore=0 phishscore=0 clxscore=1015 impostorscore=0 adultscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011090138 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Allocate ID for vmlinux BTF. This makes it visible when iterating over all BTF objects in the system. To allow distinguishing vmlinux BTF (and later kernel module BTF) from user-provided BTFs, expose extra kernel_btf flag, as well as BTF name ("vmlinux" for vmlinux BTF, will equal to module's name for module BTF). We might want to later allow specifying BTF name for user-provided BTFs as well, if that makes sense. But currently this is reserved only for in-kernel BTFs. Having in-kernel BTFs exposed IDs will allow to extend BPF APIs that require in-kernel BTF type with ability to specify BTF types from kernel modules, not just vmlinux BTF. This will be implemented in a follow up patch set for fentry/fexit/fmod_ret/lsm/etc. Signed-off-by: Andrii Nakryiko --- include/uapi/linux/bpf.h | 3 +++ kernel/bpf/btf.c | 39 ++++++++++++++++++++++++++++++++-- tools/include/uapi/linux/bpf.h | 3 +++ 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 9879d6793e90..162999b12790 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4466,6 +4466,9 @@ struct bpf_btf_info { __aligned_u64 btf; __u32 btf_size; __u32 id; + __aligned_u64 name; + __u32 name_len; + __u32 kernel_btf; } __attribute__((aligned(8))); struct bpf_link_info { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 894ee33f4c84..663c3fb4e614 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -215,6 +215,8 @@ struct btf { struct btf *base_btf; u32 start_id; /* first type ID in this BTF (0 for base BTF) */ u32 start_str_off; /* first string offset (0 for base BTF) */ + char name[MODULE_NAME_LEN]; + bool kernel_btf; }; enum verifier_phase { @@ -4430,6 +4432,8 @@ struct btf *btf_parse_vmlinux(void) btf->data = __start_BTF; btf->data_size = __stop_BTF - __start_BTF; + btf->kernel_btf = true; + snprintf(btf->name, sizeof(btf->name), "vmlinux"); err = btf_parse_hdr(env); if (err) @@ -4455,8 +4459,13 @@ struct btf *btf_parse_vmlinux(void) bpf_struct_ops_init(btf, log); - btf_verifier_env_free(env); refcount_set(&btf->refcnt, 1); + + err = btf_alloc_id(btf); + if (err) + goto errout; + + btf_verifier_env_free(env); return btf; errout: @@ -5554,7 +5563,8 @@ int btf_get_info_by_fd(const struct btf *btf, struct bpf_btf_info info; u32 info_copy, btf_copy; void __user *ubtf; - u32 uinfo_len; + char __user *uname; + u32 uinfo_len, uname_len, name_len; uinfo = u64_to_user_ptr(attr->info.info); uinfo_len = attr->info.info_len; @@ -5571,6 +5581,31 @@ int btf_get_info_by_fd(const struct btf *btf, return -EFAULT; info.btf_size = btf->data_size; + info.kernel_btf = btf->kernel_btf; + + uname = u64_to_user_ptr(info.name); + uname_len = info.name_len; + if (!uname ^ !uname_len) + return -EINVAL; + + name_len = strlen(btf->name); + info.name_len = name_len; + + if (uname) { + if (uname_len >= name_len + 1) { + if (copy_to_user(uname, btf->name, name_len + 1)) + return -EFAULT; + } else { + char zero = '\0'; + + if (copy_to_user(uname, btf->name, uname_len - 1)) + return -EFAULT; + if (put_user(zero, uname + uname_len - 1)) + return -EFAULT; + return -ENOSPC; + } + } + if (copy_to_user(uinfo, &info, info_copy) || put_user(info_copy, &uattr->info.info_len)) return -EFAULT; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 9879d6793e90..162999b12790 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4466,6 +4466,9 @@ struct bpf_btf_info { __aligned_u64 btf; __u32 btf_size; __u32 id; + __aligned_u64 name; + __u32 name_len; + __u32 kernel_btf; } __attribute__((aligned(8))); struct bpf_link_info {