From patchwork Thu Jul 9 00:56:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11653139 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4A3A3739 for ; Thu, 9 Jul 2020 00:57:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D6C220772 for ; Thu, 9 Jul 2020 00:57:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="fKxXjjJm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726260AbgGIA5D (ORCPT ); Wed, 8 Jul 2020 20:57:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726213AbgGIA5C (ORCPT ); Wed, 8 Jul 2020 20:57:02 -0400 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 ACD11C03541E for ; Wed, 8 Jul 2020 17:57:01 -0700 (PDT) Received: by mail-wm1-x342.google.com with SMTP id a6so5079712wmm.0 for ; Wed, 08 Jul 2020 17:57:01 -0700 (PDT) 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=G6LDMWBimly/S6HLQdr62HUq5FOYHBE4+UIvjiG4swM=; b=fKxXjjJmt7Tja0v5f2skLPMiQiomHlm0rzdDapCsFItn+qurOuzlwlpPwi7Wv/7Bgq TSrPwFz+IHJGaJV9KOv6pC33zWJ2IL+IqbRtbW3y5I26j748i/QhILTk/R3r7llYWJq+ wyx+Yp79PHMVoxw24nZr0hy/ziiCvUIuokIL4= 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=G6LDMWBimly/S6HLQdr62HUq5FOYHBE4+UIvjiG4swM=; b=bySdfeF5Bsx4YfCnUKJVpoUc07IJQz//0QDe8ZdaeBPb69NUpryK5amkzJnCBPszIr HoFeyBkeVtnZPJecyx350ILIfwuLuH4I34qMtHoljy6Q22ViEvRit/WOB92l8Z2cwzU6 Jf0K2Isp1JJSLBlLX1fxeDfWbsaX988k++/JSh4URQpqDvfaHP02zixYhhS0fo4zvt/I BnK6nKRBym8xiTiQPFyiMvGtshgSG04rmi4VuZ1aqUkTAmCRT6dc+1XCqtbOGjWc0LzP 0qkf3w6CjcFq2mxIiwOsp1MNpTvwBXZ9EGCPFaE4xqtIb7tmGWXvzSEZzf+6ikqH0UQl 2BHA== X-Gm-Message-State: AOAM530sDjDGVhINMVkdjD3ZyGy394KElyb1K+BDyqt/QkYc7Lnf0JeN D41YIQoXRo0kExCmGcdm2pJhuA== X-Google-Smtp-Source: ABdhPJymvSt3aawLOrI0rKXLQ7Qv7Yu5qd9/qTrjdfn7ORQsQ6UjgWYPtndARnoulfP6qegsRR2M7w== X-Received: by 2002:a1c:e908:: with SMTP id q8mr12387914wmc.59.1594256220345; Wed, 08 Jul 2020 17:57:00 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id f15sm2465498wrx.91.2020.07.08.17.56.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Jul 2020 17:56:59 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Paul Turner , Jann Horn , Florent Revest Subject: [PATCH bpf-next v3 3/4] bpf: Allow local storage to be used from LSM programs Date: Thu, 9 Jul 2020 02:56:53 +0200 Message-Id: <20200709005654.3324272-4-kpsingh@chromium.org> X-Mailer: git-send-email 2.27.0.389.gc38d7665816-goog In-Reply-To: <20200709005654.3324272-1-kpsingh@chromium.org> References: <20200709005654.3324272-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: KP Singh Adds support for both bpf_{sk, inode}_storage_{get, delete} to be used in LSM programs. These helpers are not used for tracing programs (currently) as their usage is tied to the life-cycle of the object and should only be used where the owning object won't be freed (when the owning object is passed as an argument to the LSM hook). Thus, they are safer to use in LSM hooks than tracing. Usage of local storage in tracing programs will probably follow a per function based whitelist approach. Since the UAPI helper signature for bpf_sk_storage expect a bpf_sock, it, leads to a compilation warning for LSM programs, it's also updated to accept a void * pointer instead. Signed-off-by: KP Singh --- include/net/bpf_sk_storage.h | 2 ++ include/uapi/linux/bpf.h | 4 ++-- kernel/bpf/bpf_lsm.c | 21 ++++++++++++++++++++- net/core/bpf_sk_storage.c | 22 ++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 4 ++-- 5 files changed, 48 insertions(+), 5 deletions(-) diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h index 5036c94c0503..d231da1b57ca 100644 --- a/include/net/bpf_sk_storage.h +++ b/include/net/bpf_sk_storage.h @@ -9,6 +9,8 @@ void bpf_sk_storage_free(struct sock *sk); extern const struct bpf_func_proto bpf_sk_storage_get_proto; extern const struct bpf_func_proto bpf_sk_storage_delete_proto; +extern const struct bpf_func_proto sk_storage_get_btf_proto; +extern const struct bpf_func_proto sk_storage_delete_btf_proto; struct bpf_sk_storage_diag; struct sk_buff; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 42fc442f4586..3d2859ccc7ae 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2787,7 +2787,7 @@ union bpf_attr { * * **-ERANGE** if resulting value was out of range. * - * void *bpf_sk_storage_get(struct bpf_map *map, struct bpf_sock *sk, void *value, u64 flags) + * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags) * Description * Get a bpf-local-storage from a *sk*. * @@ -2815,7 +2815,7 @@ union bpf_attr { * **NULL** if not found or there was an error in adding * a new bpf-local-storage. * - * long bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk) + * long bpf_sk_storage_delete(struct bpf_map *map, void *sk) * Description * Delete a bpf-local-storage from a *sk*. * Return diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index fb278144e9fd..9cd1428c7199 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -11,6 +11,8 @@ #include #include #include +#include +#include /* For every LSM hook that allows attachment of BPF programs, declare a nop * function where a BPF program can be attached. @@ -45,10 +47,27 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, return 0; } +static const struct bpf_func_proto * +bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + switch (func_id) { + case BPF_FUNC_inode_storage_get: + return &bpf_inode_storage_get_proto; + case BPF_FUNC_inode_storage_delete: + return &bpf_inode_storage_delete_proto; + case BPF_FUNC_sk_storage_get: + return &sk_storage_get_btf_proto; + case BPF_FUNC_sk_storage_delete: + return &sk_storage_delete_btf_proto; + default: + return tracing_prog_func_proto(func_id, prog); + } +} + const struct bpf_prog_ops lsm_prog_ops = { }; const struct bpf_verifier_ops lsm_verifier_ops = { - .get_func_proto = tracing_prog_func_proto, + .get_func_proto = bpf_lsm_func_proto, .is_valid_access = btf_ctx_access, }; diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 62b6526acf7e..add0340e9ad3 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -455,6 +455,28 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = { .arg2_type = ARG_PTR_TO_SOCKET, }; +static int sk_storage_get_btf_ids[4]; +const struct bpf_func_proto sk_storage_get_btf_proto = { + .func = bpf_sk_storage_get, + .gpl_only = false, + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, + .arg4_type = ARG_ANYTHING, + .btf_id = sk_storage_get_btf_ids, +}; + +static int sk_storage_delete_btf_ids[2]; +const struct bpf_func_proto sk_storage_delete_btf_proto = { + .func = bpf_sk_storage_delete, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .btf_id = sk_storage_delete_btf_ids, +}; + struct bpf_sk_storage_diag { u32 nr_maps; struct bpf_map *maps[]; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 42fc442f4586..3d2859ccc7ae 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2787,7 +2787,7 @@ union bpf_attr { * * **-ERANGE** if resulting value was out of range. * - * void *bpf_sk_storage_get(struct bpf_map *map, struct bpf_sock *sk, void *value, u64 flags) + * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags) * Description * Get a bpf-local-storage from a *sk*. * @@ -2815,7 +2815,7 @@ union bpf_attr { * **NULL** if not found or there was an error in adding * a new bpf-local-storage. * - * long bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk) + * long bpf_sk_storage_delete(struct bpf_map *map, void *sk) * Description * Delete a bpf-local-storage from a *sk*. * Return