From patchwork Thu Jul 23 11:50:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11680723 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 1FF2613B4 for ; Thu, 23 Jul 2020 11:50:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 01EFD20684 for ; Thu, 23 Jul 2020 11:50:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="SJGjVjzP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728614AbgGWLuy (ORCPT ); Thu, 23 Jul 2020 07:50:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728590AbgGWLum (ORCPT ); Thu, 23 Jul 2020 07:50:42 -0400 Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9121C0619DC for ; Thu, 23 Jul 2020 04:50:41 -0700 (PDT) Received: by mail-ej1-x641.google.com with SMTP id w9so6039436ejc.8 for ; Thu, 23 Jul 2020 04:50:41 -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=gp0OnWT+ezEb5kvY+8ZpcjBj/ySeUlAdu5kTWrUzIIE=; b=SJGjVjzP8rV8bHN0hURbEmOUemEZKyHCmLmbU5t1IqrcYfAz9Yc4qs/UZt6aOGq9ax zWeSBdu/2efUcyzI7ToDE8kNjFFjkGE4rcVVwRL/NikUyFTE5kMm6fvnJDwusC2eGabf 7tGi2ox4sciFYQzavi2v6KqEhS43mWQl63NEQ= 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=gp0OnWT+ezEb5kvY+8ZpcjBj/ySeUlAdu5kTWrUzIIE=; b=j5KU4N0KmybmPCovxWixLIkLHVI5owgcRgNq23hRXg8sG+hrhpHUbsF8C0qxVLaKVb c2aAB54YrF1adhp+3yCBF+Cn7Yskg5az16gEdJFq2LkAUPBDXAEdiFOC+l4phL+R5WJC sxrHLfv5rLbQ4MFTzqian4jm+lvrhCxagiwdScppRquZNm7FH/7j3vGcjOJjfLBw/Fvb J5/s0zmmF54vDSXN2wIT2m/L5YV4IXHVNwPLRjLeHtRj6+i1XAWyFoosaHite2+LyCwB Bp0EHMVjcYRSo08ohNABhJgl6Ut0HYrPG0ZVNAJ4x1gS8oNXIfDNlQpCzsCa9/hAsDur K+Cw== X-Gm-Message-State: AOAM533251VBQoYDBQxNMp0SQtMuxu7xDl/m0q8r3Tt9WdhSD35zsSPS 0eM9A02+96zzPVlR1Kp7SipnmQ== X-Google-Smtp-Source: ABdhPJxVN0OCgkV9RwzlpjwR38cvbi/IIV4Mhj4Tq2mZW+/1KLTmdV5rQSZkAZosPUf5UxuIpVmvvA== X-Received: by 2002:a17:906:b795:: with SMTP id dt21mr1790983ejb.68.1595505040223; Thu, 23 Jul 2020 04:50:40 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id h27sm579302eje.23.2020.07.23.04.50.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Jul 2020 04:50:39 -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 , Martin KaFai Lau , Paul Turner , Jann Horn , Florent Revest Subject: [PATCH bpf-next v6 6/7] bpf: Allow local storage to be used from LSM programs Date: Thu, 23 Jul 2020 13:50:31 +0200 Message-Id: <20200723115032.460770-7-kpsingh@chromium.org> X-Mailer: git-send-email 2.28.0.rc0.105.gf9edc3c819-goog In-Reply-To: <20200723115032.460770-1-kpsingh@chromium.org> References: <20200723115032.460770-1-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 | 8 ++++++-- kernel/bpf/bpf_lsm.c | 21 ++++++++++++++++++++- net/core/bpf_sk_storage.c | 27 +++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 8 ++++++-- 5 files changed, 61 insertions(+), 5 deletions(-) diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h index 4cdf37ac278c..d123807b5083 100644 --- a/include/net/bpf_sk_storage.h +++ b/include/net/bpf_sk_storage.h @@ -19,6 +19,8 @@ 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 0bdfbe6067be..5be19f93b159 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2790,7 +2790,7 @@ 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*. * @@ -2806,6 +2806,10 @@ union bpf_attr { * "type". The bpf-local-storage "type" (i.e. the *map*) is * searched against all bpf-local-storages residing at *sk*. * + * For socket programs, *sk* should be a **struct bpf_sock** pointer + * and an **ARG_PTR_TO_BTF_ID** of type **struct sock** for LSM + * programs. + * * An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be * used such that a new bpf-local-storage will be * created if one does not exist. *value* can be used @@ -2818,7 +2822,7 @@ 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 be0ed44d0887..17efb8a9196d 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -11,6 +11,7 @@ #include #include #include +#include DEFINE_BPF_STORAGE_CACHE(sk_cache); @@ -465,6 +466,32 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = { .arg2_type = ARG_PTR_TO_SOCKET, }; +BTF_ID_LIST(sk_storage_get_btf_ids) +BTF_ID(struct, sock) + +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, +}; + +BTF_ID_LIST(sk_storage_delete_btf_ids) +BTF_ID(struct, sock) + +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 0bdfbe6067be..5be19f93b159 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2790,7 +2790,7 @@ 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*. * @@ -2806,6 +2806,10 @@ union bpf_attr { * "type". The bpf-local-storage "type" (i.e. the *map*) is * searched against all bpf-local-storages residing at *sk*. * + * For socket programs, *sk* should be a **struct bpf_sock** pointer + * and an **ARG_PTR_TO_BTF_ID** of type **struct sock** for LSM + * programs. + * * An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be * used such that a new bpf-local-storage will be * created if one does not exist. *value* can be used @@ -2818,7 +2822,7 @@ 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