From patchwork Thu Nov 12 20:09:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florent Revest X-Patchwork-Id: 11901395 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=-12.8 required=3.0 tests=BAYES_00,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, URIBL_BLOCKED,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 9FC30C388F7 for ; Thu, 12 Nov 2020 20:10:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47AE42085B for ; Thu, 12 Nov 2020 20:10:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="ctMlC2wc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727147AbgKLUKL (ORCPT ); Thu, 12 Nov 2020 15:10:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727097AbgKLUKL (ORCPT ); Thu, 12 Nov 2020 15:10:11 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6972BC0613D4 for ; Thu, 12 Nov 2020 12:10:09 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id b6so7355466wrt.4 for ; Thu, 12 Nov 2020 12:10:09 -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:mime-version :content-transfer-encoding; bh=y94nwo1CEggXD4knbaMbqIkUnYdaP7pApPBKsxsL/8U=; b=ctMlC2wcU5DQ1hCfy3zQObIY743O1hB6k3yheXjapLwE3074ggej2sU/Pg7B3yVv8V 8CvceXjn5sQ8lx1kDb1Hqtxd0azQf2J6E12jPzEchymNcLT2o+wvmTGDpxiRlf0Wy3uF FxGNLgnOXfuTCk5s4n8tYG/ND11qxSr5RcVZU= 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:mime-version :content-transfer-encoding; bh=y94nwo1CEggXD4knbaMbqIkUnYdaP7pApPBKsxsL/8U=; b=XM2nzD0UAME14byCcgcVG8ZH/9CeJKdx/ed+s+xkaqhBGyZoQZUQSUvZyPIlwqE7sc EmQ0MVej/RoZo8k3Anayalra+u9zRAFiy1LTrxAlO4/+qffj2xO3P3mKdr+5h0BOCvpF lwiybabCRflO6VPv42PvIgXLTXg+FDQoQb52infm8gJB1GO5zHzntyn2E4CnoNXMtAfJ jnJ5M/QnjS+qsDqjSSdmsHa/b0O+YNElSIfFpe7csyhg48VVVBwyDrhm5gpRYtEt+3xZ +QHKSp7lLSfLJKE7h9rK4k9kK7Ppq4DFlc9KMoPKcOdu3RX7yUSIOFSRt9jz5JbDXi9w UA9Q== X-Gm-Message-State: AOAM533/EaswAdEI9wQpJ6Bw+sdYu6nkGnDZCXo7E9yM5FSfb5FbCfnH EgFpy8hNbwdc1l/Yv4BVv5r1cQHEchY+KZ9L X-Google-Smtp-Source: ABdhPJzfpLBsthkujmLfBJyhImkhpL1qzj+rdg96IvKaJnWitJXj1nf7M17nWUh1U2Ku2jXjbpWNpQ== X-Received: by 2002:a5d:548b:: with SMTP id h11mr1461329wrv.306.1605211807921; Thu, 12 Nov 2020 12:10:07 -0800 (PST) Received: from revest.zrh.corp.google.com ([2a00:79e0:42:204:f693:9fff:fef4:a569]) by smtp.gmail.com with ESMTPSA id g138sm7767970wme.39.2020.11.12.12.10.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Nov 2020 12:10:07 -0800 (PST) From: Florent Revest To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, yhs@fb.com, andrii@kernel.org, kpsingh@chromium.org, jackmanb@chromium.org, linux-kernel@vger.kernel.org, Florent Revest Subject: [PATCH] bpf: Expose a bpf_sock_from_file helper to tracing programs Date: Thu, 12 Nov 2020 21:09:44 +0100 Message-Id: <20201112200944.2726451-1-revest@chromium.org> X-Mailer: git-send-email 2.29.2.222.g5d2a92d10f8-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Florent Revest eBPF programs can already check whether a file is a socket using file->f_op == &socket_file_ops but they can not convert file->private_data into a struct socket with BTF information. For that, we need a new helper that is essentially just a wrapper for sock_from_file. sock_from_file can set an err value but this is only set to -ENOTSOCK when the return value is NULL so it's useless superfluous information. Signed-off-by: Florent Revest Reported-by: kernel test robot --- include/uapi/linux/bpf.h | 7 +++++++ kernel/trace/bpf_trace.c | 22 ++++++++++++++++++++++ scripts/bpf_helpers_doc.py | 4 ++++ tools/include/uapi/linux/bpf.h | 7 +++++++ 4 files changed, 40 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 162999b12790..6c96bf9c1f94 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 3530120fa280..d040d3ec8313 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1255,6 +1255,26 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = { .arg5_type = ARG_ANYTHING, }; +BPF_CALL_1(bpf_sock_from_file, struct file *, file) +{ + int err; + + return (unsigned long) sock_from_file(file, &err); +} + +BTF_ID_LIST(bpf_sock_from_file_btf_ids) +BTF_ID(struct, socket) +BTF_ID(struct, file) + +const struct bpf_func_proto bpf_sock_from_file_proto = { + .func = bpf_sock_from_file, + .gpl_only = true, + .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) { @@ -1349,6 +1369,8 @@ 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 6769caae142f..99068ec40315 100755 --- a/scripts/bpf_helpers_doc.py +++ b/scripts/bpf_helpers_doc.py @@ -434,6 +434,8 @@ class PrinterHelpers(Printer): 'struct xdp_md', 'struct path', 'struct btf_ptr', + 'struct socket', + 'struct file', ] known_types = { '...', @@ -477,6 +479,8 @@ 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..6c96bf9c1f94 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