From patchwork Thu Nov 19 16:26:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 11918225 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 F0A10C64E7C for ; Thu, 19 Nov 2020 16:27:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AAF8F246F2 for ; Thu, 19 Nov 2020 16:27:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="MhBFhMPu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728954AbgKSQ1q (ORCPT ); Thu, 19 Nov 2020 11:27:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54032 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728836AbgKSQ1f (ORCPT ); Thu, 19 Nov 2020 11:27:35 -0500 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A80E1C0617A7 for ; Thu, 19 Nov 2020 08:27:34 -0800 (PST) Received: by mail-wm1-x342.google.com with SMTP id p22so7765727wmg.3 for ; Thu, 19 Nov 2020 08:27:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=LJ5w1Vm2fOQoGe4AXB6MlgyVSNcAAyyh/BtZV/T1bVw=; b=MhBFhMPuplgXvXL8UeQnB2kwL2CIQzlplPxykO2DMN511aL8mCGLeL4736LwoRsVaN o8KF/zccNgZmk3/N7qeW+uE6VBsJ8/yxiISWSgjl3OrRf4OfDebaEO3E7TiW6sa8hN0q ObbI5EjlMQcLp/k4CL8YU4g+8fDDROk2SYaj8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=LJ5w1Vm2fOQoGe4AXB6MlgyVSNcAAyyh/BtZV/T1bVw=; b=EVsvDa1XeXrsE+HUPDaBQp8csyiICb/CGiieR6hG+FdUSdrBi4TXZkYLKcSCYr+Eio uYdj42PClegYpHQ51dU62SrXuheKItwU+Kk9lxemRsGTgDTd//vgZVrx2d6T0ERp+Vqb ZM/X0urQq/CgLqKDN4LFXbb3WDPARhIG44CrPxpBfONm40r49xs4yP73OTOBt1f90seh AbqlfFN3I1b4AXGPM+X1o1FxjHcrnrVVC7BEsNdLM6we2bWed2NToBJ4jsRLNk0zuZ2s EmYYTV8duPfkzXB5VQ9dGYU4n6wm0y4vLthQbJPF5f4NDDGmejuZs4l108YY4tPO2Bya 6Wmw== X-Gm-Message-State: AOAM531y4DHQe0/5EQ892FRNJZi0MGDv+VekQAsOYTZtqKKlizU2gAUR FcJ1UocsG1Ay1RbxVEYb0AR9vYEHYF0yWTdS X-Google-Smtp-Source: ABdhPJyNyQuqHUq3rxhKcDmCkFUo31tIBP13bp1m6OUKnrlC8+DFrspWSXC+Y2g26q8Ue8mvHj5dOg== X-Received: by 2002:a05:600c:2048:: with SMTP id p8mr5570835wmg.165.1605803252994; Thu, 19 Nov 2020 08:27:32 -0800 (PST) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:f693:9fff:fef4:a569]) by smtp.gmail.com with ESMTPSA id i5sm380061wrw.45.2020.11.19.08.27.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Nov 2020 08:27:32 -0800 (PST) From: Florent Revest To: bpf@vger.kernel.org Cc: viro@zeniv.linux.org.uk, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, yhs@fb.com, andrii@kernel.org, kpsingh@chromium.org, revest@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v2 2/5] bpf: Add a bpf_sock_from_file helper Date: Thu, 19 Nov 2020 17:26:51 +0100 Message-Id: <20201119162654.2410685-2-revest@chromium.org> X-Mailer: git-send-email 2.29.2.299.gdc1121823c-goog In-Reply-To: <20201119162654.2410685-1-revest@chromium.org> References: <20201119162654.2410685-1-revest@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Florent Revest While eBPF programs can check whether a file is a socket by file->f_op == &socket_file_ops, they cannot convert the void private_data pointer to a struct socket BTF pointer. In order to do this a new helper wrapping sock_from_file is added. This is useful to tracing programs but also other program types inheriting this set of helpers such as iterators or LSM programs. Signed-off-by: Florent Revest Acked-by: KP Singh Acked-by: Martin KaFai Lau --- include/uapi/linux/bpf.h | 7 +++++++ kernel/trace/bpf_trace.c | 20 ++++++++++++++++++++ scripts/bpf_helpers_doc.py | 4 ++++ tools/include/uapi/linux/bpf.h | 7 +++++++ 4 files changed, 38 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 162999b12790..7d598f161dc0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3787,6 +3787,12 @@ union bpf_attr { * *ARG_PTR_TO_BTF_ID* of type *task_struct*. * Return * Pointer to the current task. + * + * struct socket *bpf_sock_from_file(struct file *file) + * Description + * If the given file contains a socket, returns the associated socket. + * Return + * A pointer to a struct socket on success or NULL on failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3948,6 +3954,7 @@ union bpf_attr { FN(task_storage_get), \ FN(task_storage_delete), \ FN(get_current_task_btf), \ + FN(sock_from_file), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 02986c7b90eb..d87ca6f93c58 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1260,6 +1260,24 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = { .arg5_type = ARG_ANYTHING, }; +BPF_CALL_1(bpf_sock_from_file, struct file *, file) +{ + return (unsigned long) sock_from_file(file); +} + +BTF_ID_LIST(bpf_sock_from_file_btf_ids) +BTF_ID(struct, socket) +BTF_ID(struct, file) + +static const struct bpf_func_proto bpf_sock_from_file_proto = { + .func = bpf_sock_from_file, + .gpl_only = false, + .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, + .ret_btf_id = &bpf_sock_from_file_btf_ids[0], + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_btf_id = &bpf_sock_from_file_btf_ids[1], +}; + const struct bpf_func_proto * bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { @@ -1354,6 +1372,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_per_cpu_ptr_proto; case BPF_FUNC_bpf_this_cpu_ptr: return &bpf_this_cpu_ptr_proto; + case BPF_FUNC_sock_from_file: + return &bpf_sock_from_file_proto; default: return NULL; } diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py index 31484377b8b1..d609f20e8360 100755 --- a/scripts/bpf_helpers_doc.py +++ b/scripts/bpf_helpers_doc.py @@ -435,6 +435,8 @@ class PrinterHelpers(Printer): 'struct xdp_md', 'struct path', 'struct btf_ptr', + 'struct socket', + 'struct file', ] known_types = { '...', @@ -478,6 +480,8 @@ class PrinterHelpers(Printer): 'struct task_struct', 'struct path', 'struct btf_ptr', + 'struct socket', + 'struct file', } mapped_types = { 'u8': '__u8', diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 162999b12790..7d598f161dc0 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3787,6 +3787,12 @@ union bpf_attr { * *ARG_PTR_TO_BTF_ID* of type *task_struct*. * Return * Pointer to the current task. + * + * struct socket *bpf_sock_from_file(struct file *file) + * Description + * If the given file contains a socket, returns the associated socket. + * Return + * A pointer to a struct socket on success or NULL on failure. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3948,6 +3954,7 @@ union bpf_attr { FN(task_storage_get), \ FN(task_storage_delete), \ FN(get_current_task_btf), \ + FN(sock_from_file), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper