From patchwork Wed Jun 17 20:29:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11610535 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 A48E9912 for ; Wed, 17 Jun 2020 20:29:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D48F21532 for ; Wed, 17 Jun 2020 20:29:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="AquIAq5n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726853AbgFQU3x (ORCPT ); Wed, 17 Jun 2020 16:29:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726986AbgFQU3v (ORCPT ); Wed, 17 Jun 2020 16:29:51 -0400 Received: from mail-wm1-x343.google.com (mail-wm1-x343.google.com [IPv6:2a00:1450:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37249C0613EE for ; Wed, 17 Jun 2020 13:29:51 -0700 (PDT) Received: by mail-wm1-x343.google.com with SMTP id r9so3130798wmh.2 for ; Wed, 17 Jun 2020 13:29:51 -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=ap3xo3wk7ngmLhz5XWEnW0IF0vRvINTquEf3Jswtafk=; b=AquIAq5nNA/hYZnZ3GsMW+/mJbzUKY9SzGYeAJrrFUIVpzJz1frhdE5JviNQXJdCPS NL7Upk9JbEHu0JmP5Qi9kSuIhpuU4jG9zsddrIZRFKhknmvRjv69jEGd21EAp2gPK20S 1rJ8WEE5L4McKyJOsUGzt1HGdt8/GpmM1OWCs= 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=ap3xo3wk7ngmLhz5XWEnW0IF0vRvINTquEf3Jswtafk=; b=EhMKp384sqkQT+RzCzUajR14NbvyCPOu2QMIugpNs4I7Kq8Pp4CYx4+ebvSA9ToGQL uwc8HM7Wkl6Rb4tpuTYFv31GW60TCfBjzWWKFMGVTLKI/NzsS77U4TbkaZmaodNMkgX7 B1jDAbXsI/UzQD0TFuoO/6nuYDJpTgPv+zMddqnG4u0xTqJIXFmjEV3/phbZYDd8kah6 Vx/4bK6a2amJW4QBhONvmuQYRwOnZhrYopfvE7lg0BSvuhzwKVYDfKRuWuPMLxdKX2q9 oUJMb/D8h0tT/VrJ3LgREonknPUQDo3G7KuRv8dOMc+54610IKAn5aROQPMBytf5VfLg yEFQ== X-Gm-Message-State: AOAM530K1ymr6IUSt2t3qMEL0V91GymFhqMu+wmSK59Pv802a0dQmDPp P41HMc1LyCAxqyxAP0DNRyhLXA== X-Google-Smtp-Source: ABdhPJyUdSDwhXpkqwu1uaBYYrlvkyUN4ejqH0LH9wuS++eyfOOnkkPgJP0kJh108YmSpY7afCqm8A== X-Received: by 2002:a05:600c:28e:: with SMTP id 14mr422286wmk.167.1592425789841; Wed, 17 Jun 2020 13:29:49 -0700 (PDT) Received: from kpsingh.zrh.corp.google.com ([81.6.44.51]) by smtp.gmail.com with ESMTPSA id o10sm812845wrq.40.2020.06.17.13.29.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Jun 2020 13:29:49 -0700 (PDT) From: KP Singh To: bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , Paul Turner , Jann Horn Subject: [PATCH bpf-next v2 3/4] bpf: Allow local storage to be used from LSM programs Date: Wed, 17 Jun 2020 22:29:40 +0200 Message-Id: <20200617202941.3034-4-kpsingh@chromium.org> X-Mailer: git-send-email 2.27.0.111.gc72c7da667-goog In-Reply-To: <20200617202941.3034-1-kpsingh@chromium.org> References: <20200617202941.3034-1-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/linux/bpf_local_storage.h | 2 ++ include/uapi/linux/bpf.h | 4 ++-- kernel/bpf/bpf_local_storage.c | 22 ++++++++++++++++++++++ kernel/bpf/bpf_lsm.c | 20 +++++++++++++++++++- tools/include/uapi/linux/bpf.h | 4 ++-- 5 files changed, 47 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 7488487b1099..cf43ed0b6c3b 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -10,6 +10,8 @@ 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; extern const struct bpf_func_proto bpf_inode_storage_get_proto; extern const struct bpf_func_proto bpf_inode_storage_delete_proto; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 679a50562e72..6867e24f8c77 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2783,7 +2783,7 @@ 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*. * @@ -2811,7 +2811,7 @@ union bpf_attr { * **NULL** if not found or there was an error in adding * a new bpf-local-storage. * - * int bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk) + * int 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_local_storage.c b/kernel/bpf/bpf_local_storage.c index 572ed711c3fd..c944fc0cc81d 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -1276,6 +1276,28 @@ const struct bpf_func_proto bpf_inode_storage_delete_proto = { .btf_id = bpf_inode_storage_delete_btf_ids, }; +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/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index fb278144e9fd..e97dbbf56285 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -11,6 +11,7 @@ #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 +46,27 @@ 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/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 679a50562e72..6867e24f8c77 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2783,7 +2783,7 @@ 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*. * @@ -2811,7 +2811,7 @@ union bpf_attr { * **NULL** if not found or there was an error in adding * a new bpf-local-storage. * - * int bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk) + * int bpf_sk_storage_delete(struct bpf_map *map, void *sk) * Description * Delete a bpf-local-storage from a *sk*. * Return