From patchwork Sat Nov 21 02:46:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 11923107 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=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 84796C2D0E4 for ; Sat, 21 Nov 2020 02:46:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50E3822403 for ; Sat, 21 Nov 2020 02:46:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726982AbgKUCqd convert rfc822-to-8bit (ORCPT ); Fri, 20 Nov 2020 21:46:33 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:21180 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725785AbgKUCqc (ORCPT ); Fri, 20 Nov 2020 21:46:32 -0500 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AL2eG4t017818 for ; Fri, 20 Nov 2020 18:46:31 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 34xat44x38-11 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 20 Nov 2020 18:46:31 -0800 Received: from intmgw004.03.ash8.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:21d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 20 Nov 2020 18:46:26 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id A4A0D2EC9CD8; Fri, 20 Nov 2020 18:46:24 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 2/7] bpf: allow to specify kernel module BTFs when attaching BPF programs Date: Fri, 20 Nov 2020 18:46:11 -0800 Message-ID: <20201121024616.1588175-3-andrii@kernel.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201121024616.1588175-1-andrii@kernel.org> References: <20201121024616.1588175-1-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=2020-11-20_17:2020-11-20,2020-11-20 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 impostorscore=0 mlxscore=0 adultscore=0 malwarescore=0 bulkscore=0 suspectscore=8 lowpriorityscore=0 phishscore=0 clxscore=1015 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011210019 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add ability for user-space programs to specify non-vmlinux BTF when attaching BTF-powered BPF programs: raw_tp, fentry/fexit/fmod_ret, LSM, etc. For this, add attach_btf_obj_id field which contains BTF object ID for either vmlinux or module. For backwards compatibility (and simplicity) reasons, 0 denotes vmlinux BTF. Only kernel BTF (vmlinux or module) can be specified. Signed-off-by: Andrii Nakryiko --- include/linux/btf.h | 2 ++ include/uapi/linux/bpf.h | 1 + kernel/bpf/btf.c | 25 +++++++++++++++++++------ kernel/bpf/syscall.c | 22 +++++++++++++++++++--- tools/include/uapi/linux/bpf.h | 1 + 5 files changed, 42 insertions(+), 9 deletions(-) diff --git a/include/linux/btf.h b/include/linux/btf.h index fb608e4de076..53ce2bc6dc54 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -89,7 +89,9 @@ int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj, char *buf, int len, u64 flags); int btf_get_fd_by_id(u32 id); +struct btf *btf_get_by_id(int id); u32 btf_obj_id(const struct btf *btf); +bool btf_is_kernel(const struct btf *btf); bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s, const struct btf_member *m, u32 expected_offset, u32 expected_size); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3ca6146f001a..782169dc41e0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -558,6 +558,7 @@ union bpf_attr { __u32 line_info_cnt; /* number of bpf_line_info records */ __u32 attach_btf_id; /* in-kernel BTF type id to attach to */ __u32 attach_prog_fd; /* 0 to attach to vmlinux */ + __u32 attach_btf_obj_id; /* vmlinux/module BTF object ID for BTF type */ }; struct { /* anonymous struct used by BPF_OBJ_* commands */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 7a19bf5bfe97..12876b272c6b 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5652,6 +5652,19 @@ struct btf *btf_get_by_fd(int fd) return btf; } +struct btf *btf_get_by_id(int id) +{ + struct btf *btf; + + rcu_read_lock(); + btf = idr_find(&btf_idr, id); + if (!btf || !refcount_inc_not_zero(&btf->refcnt)) + btf = ERR_PTR(-ENOENT); + rcu_read_unlock(); + + return btf; +} + int btf_get_info_by_fd(const struct btf *btf, const union bpf_attr *attr, union bpf_attr __user *uattr) @@ -5717,12 +5730,7 @@ int btf_get_fd_by_id(u32 id) struct btf *btf; int fd; - rcu_read_lock(); - btf = idr_find(&btf_idr, id); - if (!btf || !refcount_inc_not_zero(&btf->refcnt)) - btf = ERR_PTR(-ENOENT); - rcu_read_unlock(); - + btf = btf_get_by_id(id); if (IS_ERR(btf)) return PTR_ERR(btf); @@ -5738,6 +5746,11 @@ u32 btf_obj_id(const struct btf *btf) return btf->id; } +bool btf_is_kernel(const struct btf *btf) +{ + return btf->kernel_btf; +} + static int btf_id_cmp_func(const void *a, const void *b) { const int *pa = a, *pb = b; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 5ee00611af53..3af073642664 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1968,7 +1968,7 @@ static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr) static int bpf_prog_load_check_attach(enum bpf_prog_type prog_type, enum bpf_attach_type expected_attach_type, - u32 btf_id, u32 prog_fd) + u32 btf_obj_id, u32 btf_id, u32 prog_fd) { if (btf_id) { if (btf_id > BTF_MAX_TYPE) @@ -1985,6 +1985,9 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type, } } + if (btf_obj_id && (!btf_id || prog_fd)) + return -EINVAL; + if (prog_fd && prog_type != BPF_PROG_TYPE_TRACING && prog_type != BPF_PROG_TYPE_EXT) return -EINVAL; @@ -2097,7 +2100,7 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type) } /* last field in 'union bpf_attr' used by this command */ -#define BPF_PROG_LOAD_LAST_FIELD attach_prog_fd +#define BPF_PROG_LOAD_LAST_FIELD attach_btf_obj_id static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr) { @@ -2146,6 +2149,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr) bpf_prog_load_fixup_attach_type(attr); if (bpf_prog_load_check_attach(type, attr->expected_attach_type, + attr->attach_btf_obj_id, attr->attach_btf_id, attr->attach_prog_fd)) return -EINVAL; @@ -2158,7 +2162,19 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr) prog->expected_attach_type = attr->expected_attach_type; prog->aux->attach_btf_id = attr->attach_btf_id; - if (attr->attach_btf_id && !attr->attach_prog_fd) { + if (attr->attach_btf_obj_id) { + struct btf *btf; + + btf = btf_get_by_id(attr->attach_btf_obj_id); + if (IS_ERR(btf)) + return PTR_ERR(btf); + if (!btf_is_kernel(btf)) { + btf_put(btf); + return -EINVAL; + } + + prog->aux->attach_btf = btf; + } else if (attr->attach_btf_id && !attr->attach_prog_fd) { struct btf *btf; btf = bpf_get_btf_vmlinux(); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3ca6146f001a..782169dc41e0 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -558,6 +558,7 @@ union bpf_attr { __u32 line_info_cnt; /* number of bpf_line_info records */ __u32 attach_btf_id; /* in-kernel BTF type id to attach to */ __u32 attach_prog_fd; /* 0 to attach to vmlinux */ + __u32 attach_btf_obj_id; /* vmlinux/module BTF object ID for BTF type */ }; struct { /* anonymous struct used by BPF_OBJ_* commands */