From patchwork Mon Dec 6 23:22:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Luo X-Patchwork-Id: 12660495 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CEF1C433EF for ; Mon, 6 Dec 2021 23:22:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245414AbhLFX0A (ORCPT ); Mon, 6 Dec 2021 18:26:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242479AbhLFX0A (ORCPT ); Mon, 6 Dec 2021 18:26:00 -0500 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E3B2C061746 for ; Mon, 6 Dec 2021 15:22:31 -0800 (PST) Received: by mail-pg1-x549.google.com with SMTP id x23-20020a634a17000000b003252e908ce3so7638484pga.1 for ; Mon, 06 Dec 2021 15:22:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=Fd6ObZ84PiwyU6QeMGO4sLjfGJds5C9mjK8ZBFR4FOc=; b=PiRqFqPe2HVTfFMqVS+bEztF+SqAT8rtvdNal52AGGhTg6FpCgEEkazJV2AJzupWRs dZJh0BxpVQvAjHE2jKNv1sWSZ0KitfcvBEoDt9mSSgtKEtOHiPxiYd9/uujq0Pc7ebpL eureaFRp7t9cRX9L4o96xiLkgL0UVqbpE0sGVR6l57HNGEI/2pdeqANJCnXF6VKTCh3k /z+4nfj+TbXrOQLq2wajMrxuIjBDmGHgppEgAvtwrT8ipKWVyOmSS+Cv2+tkfPzb4Ze+ Sf8eKchshzlMZ06IskzhyILRTqlctFWUF2pUd9gCvOYSjWI0o+Td5sLiJ2tV3HMiBcej Ekcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=Fd6ObZ84PiwyU6QeMGO4sLjfGJds5C9mjK8ZBFR4FOc=; b=UiprCWPqD4iKLugAtRdxySGMwe2c8o9jsxObZaLRDEqELUWsKFsN+wJrG1ZJI3j7qT ciQkYu8dfAH/cL5mseob/s/cJyKzzwLVUlAsR4cr4UH09bniuNfx4jMTIehiSWUZhK3v okDvX8W0AdoizYM2DrGaj6KyKJI29UZwGPYUOjhEaujtHTm6jBUV9wbiwEQcjydZlFWU l+bQifbU/p3n7KoOMn0m3Gl+d7WyvCdfKWMzMzhSTQ8p3b7VEx1/D6R5f9plHLIkukgX LGbGgpWtnW8Kcr1DZyPG7D9HpALy7JbIQuKO/CCwJP4g7mHFKx6L9HJg+Hn99KmZ4EeZ AwnQ== X-Gm-Message-State: AOAM53067CookqKTrgcSy24epW8TLwhJc6DUTi+Nsn/bikF9f11uDzQ4 rt35B8Y6TO5+YGGX6dF8JIa6auqnp/c= X-Google-Smtp-Source: ABdhPJzuEWzU1vttaNO9YnnbTs/WJIAQlOn1ubKpNLxPt3xf2sokiHHj3H3/VJnnEWPuy/aKzCMaqltIv3M= X-Received: from haoluo.svl.corp.google.com ([2620:15c:2cd:202:2977:d88c:3c3:c52a]) (user=haoluo job=sendgmr) by 2002:a63:5f11:: with SMTP id t17mr5532119pgb.388.1638832950736; Mon, 06 Dec 2021 15:22:30 -0800 (PST) Date: Mon, 6 Dec 2021 15:22:18 -0800 Message-Id: <20211206232227.3286237-1-haoluo@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.34.1.400.ga245620fadb-goog Subject: [PATCH bpf-next v1 0/9] Introduce composable bpf types From: Hao Luo To: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann Cc: Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , bpf@vger.kernel.org, Hao Luo Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net This patch set consists of two changes: - a cleanup of arg_type, ret_type and reg_type which try to make those types composable. (patch 1/9 - patch 6/9) - a bug fix that prevents bpf programs from writing kernel memory. (patch 7/9 - patch 9/9) The purpose of the cleanup is to find a scalable way to express type nullness and read-onliness. This patchset introduces two flags that can be applied on all three types: PTR_MAYBE_NULL and MEM_RDONLY. Previous types such as ARG_XXX_OR_NULL can now be written as ARG_XXX | PTR_MAYBE_NULL Similarly, PTR_TO_RDONLY_BUF is now "PTR_TO_BUF | MEM_RDONLY". Flags can be composed, as ARGs can be both MEM_RDONLY and MAYBE_NULL. ARG_PTR_TO_MEM | PTR_MAYBE_NULL | MEM_RDONLY Based on this new composable types, patch 7/9 applies MEM_RDONLY on PTR_TO_MEM, in order to tag the returned memory from per_cpu_ptr as read-only. Therefore fixing a previous bug that one can leverage per_cpu_ptr to modify kernel memory within BPF programs. Patch 8/9 generalizes the use of MEM_RDONLY further by tagging a set of helper arguments ARG_PTR_TO_MEM with MEM_RDONLY. Some helper functions may override their arguments, such as bpf_d_path, bpf_snprintf. In this patch, we narrow the ARG_PTR_TO_MEM to be compatible with only a subset of memory types. This prevents these helpers from writing read-only memories. For the helpers that do not write its arguments, we add tag MEM_RDONLY to allow taking a RDONLY memory as argument. Changes since RFC v2: - renamed BPF_BASE_TYPE to a more succinct name base_type and move its definition to bpf_verifier.h. Same for BPF_TYPE_FLAG. (Alexei) - made checking MEM_RDONLY in check_reg_type() universal (Alexei) - ran through majority of test_progs and fixed bugs in RFC v2: - fixed incorrect BPF_BASE_TYPE_MASK. The high bit of GENMASK should be BITS - 1, rather than BITS. patch 1/9. - fixed incorrect conditions when checking ARG_PTR_TO_MAP_VALUE in check_func_arg(). See patch 2/9. - fixed a bug where PTR_TO_BTF_ID may be combined with MEM_RDONLY, causing the check in check_mem_access() to fall through to the 'else' branch. See check_helper_call() in patch 7/9. - fixed build failure on netronome driver. Entries in bpf_reg_type have been ordered. patch 4/9. - fixed build warnings of using '%d' to print base_type. patch 4/9 - unify arg_type_may_be_null() and reg_type_may_be_null() into a single type_may_be_null(). Previous versions: RFC v2: https://lwn.net/Articles/877171/ RFC v1: https://lore.kernel.org/bpf/20211109003052.3499225-1-haoluo@google.com/T/ https://lore.kernel.org/bpf/20211109021624.1140446-8-haoluo@google.com/T/ Hao Luo (9): bpf: Introduce composable reg, ret and arg types. bpf: Replace ARG_XXX_OR_NULL with ARG_XXX | PTR_MAYBE_NULL bpf: Replace RET_XXX_OR_NULL with RET_XXX | PTR_MAYBE_NULL bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL bpf: Introduce MEM_RDONLY flag bpf: Convert PTR_TO_MEM_OR_NULL to composable types. bpf: Make per_cpu_ptr return rdonly PTR_TO_MEM. bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem. bpf/selftests: Test PTR_TO_RDONLY_MEM drivers/net/ethernet/netronome/nfp/bpf/fw.h | 4 +- include/linux/bpf.h | 99 +++- include/linux/bpf_verifier.h | 13 + kernel/bpf/btf.c | 12 +- kernel/bpf/cgroup.c | 2 +- kernel/bpf/helpers.c | 12 +- kernel/bpf/map_iter.c | 4 +- kernel/bpf/ringbuf.c | 2 +- kernel/bpf/syscall.c | 2 +- kernel/bpf/verifier.c | 464 ++++++++---------- kernel/trace/bpf_trace.c | 26 +- net/core/bpf_sk_storage.c | 2 +- net/core/filter.c | 64 +-- net/core/sock_map.c | 2 +- .../selftests/bpf/prog_tests/ksyms_btf.c | 14 + .../bpf/progs/test_ksyms_btf_write_check.c | 29 ++ 16 files changed, 416 insertions(+), 335 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf_write_check.c