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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 1AB04C4741F for ; Tue, 10 Nov 2020 00:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2A3F206CB for ; Tue, 10 Nov 2020 00:09:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ojQXFWTY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730134AbgKJAJu (ORCPT ); Mon, 9 Nov 2020 19:09:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729847AbgKJAJu (ORCPT ); Mon, 9 Nov 2020 19:09:50 -0500 Received: from mail-yb1-xb41.google.com (mail-yb1-xb41.google.com [IPv6:2607:f8b0:4864:20::b41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53BB3C0613CF; Mon, 9 Nov 2020 16:09:50 -0800 (PST) Received: by mail-yb1-xb41.google.com with SMTP id i186so9922752ybc.11; Mon, 09 Nov 2020 16:09:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7MrlUCPjB8KSnvLKxOJBPycaLoKpp69iwiSDtd8vsAs=; b=ojQXFWTYUtZot+KOstD0tQDSrrD83hmODcAa2toFUDVZerOksO6WLdcPT1N21KH/Mq Tpn1kNm1a/XUfur/RjQvtmzhBh0Sf4kZmM5/rm7AtkZ6GUKzBfeXw7v8481XXRVw5HWT hZVnv5022X5zvv1pKzm5FIRCYFHpDtMPA8jKIFyGPSnm0qZNJqpiM4alzdf4dZuReB0W zWMSLg6KA+FIYLpYfFB9yMAhbawbjtVyQsT8CxBw7szK5/hTyjyGbhpug20QAQnJwDx3 fWBpLXg4zvcgQ1YPFR1ma83EgOq36XOC8PN+/UtmvAhNqA+kjg0xg1WwSfghRvSreY88 Xj3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=7MrlUCPjB8KSnvLKxOJBPycaLoKpp69iwiSDtd8vsAs=; b=Ef0wQ1M/JwmTyFRqi+uy2B/zUxnkBX6j4E5ZLeWq+0RtIi32BOp5YIG0PGJZzOJIr3 NxkHC8RW7Zqv3Sc5JLen3QLdhZcRELRp0qLnPsS+9My+HS+1zVFX96xPv7pWuh9U1xzJ 1x4+nrvadXJIYMnO7wjOiG9wqSITss3b/qlnt4noOF/709P0ftr6lfv4ZPDUC9NViBeQ 2DS0TBUKr0TG56HBS6HxfAsyL/r45tDakdJcVVzLKAvgvJJObHNUlSDcAILsZwJM/mq1 /GKQwYosIq63IIGUgqOwwzkaGVUueD6Mn/WXLZa/2YW6vr/u/uIa8scr0vdyPjUbK9Ib mvUg== X-Gm-Message-State: AOAM5330LZIFt+M7YWJRoz+V7vKw8KB243wtxhDMEXtHFbnxkrLUC694 qNBTe/7Jf8vnNIAjr6ZCqzuAiNmNBEo3XKVss1dXIW3538s= X-Google-Smtp-Source: ABdhPJz8qtFeLMG3tZPgDwxvTK8M8a7V1f/6D0NHRXUpoE7XfxiO6iDVetGe9E2+t3IX2tEzCOf9YxuPp5Vp890NA1Y= X-Received: by 2002:a25:585:: with SMTP id 127mr11582225ybf.425.1604966989511; Mon, 09 Nov 2020 16:09:49 -0800 (PST) MIME-Version: 1.0 References: <20201109210024.2024572-1-andrii@kernel.org> <20201109210024.2024572-3-andrii@kernel.org> <20201109215518.jcqtsq7h7kni6w2w@kafai-mbp.dhcp.thefacebook.com> In-Reply-To: <20201109215518.jcqtsq7h7kni6w2w@kafai-mbp.dhcp.thefacebook.com> From: Andrii Nakryiko Date: Mon, 9 Nov 2020 16:09:38 -0800 Message-ID: Subject: Re: [PATCH v3 bpf-next 2/5] bpf: assign ID to vmlinux BTF and return extra info for BTF in GET_OBJ_INFO To: Martin KaFai Lau Cc: Andrii Nakryiko , bpf , Networking , Alexei Starovoitov , Daniel Borkmann , Kernel Team , open list , "Rafael J. Wysocki" , Jessica Yu , Arnaldo Carvalho de Melo , Greg Kroah-Hartman Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Nov 9, 2020 at 1:55 PM Martin KaFai Lau wrote: > > On Mon, Nov 09, 2020 at 01:00:21PM -0800, Andrii Nakryiko wrote: > > 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; > It should still do copy_to_user() even it will return -ENOSPC. > Good catch! I'll use "ret" variable, will set it to -ENOSPC here and will let the code fall through. > > + } > > + } > > + > > if (copy_to_user(uinfo, &info, info_copy) || > > put_user(info_copy, &uattr->info.info_len)) > > return -EFAULT;