From mboxrd@z Thu Jan 1 00:00:00 1970 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 B2E94C77B60 for ; Tue, 4 Apr 2023 14:47:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231972AbjDDOrH (ORCPT ); Tue, 4 Apr 2023 10:47:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231964AbjDDOq6 (ORCPT ); Tue, 4 Apr 2023 10:46:58 -0400 Received: from mail-qv1-f53.google.com (mail-qv1-f53.google.com [209.85.219.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2EE83E42; Tue, 4 Apr 2023 07:46:57 -0700 (PDT) Received: by mail-qv1-f53.google.com with SMTP id m16so23523978qvi.12; Tue, 04 Apr 2023 07:46:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680619616; x=1683211616; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=50IlSuqIBvdmyNXD4PyZ5L4D0RtsaJ6wD6o1J+jAgKo=; b=nagjYsilTLZcZ6a5N2IauoLESH3vii4U3LcW0/9ANubz3aKI8IvBufC5jGGpxOVtSv TZxousBeDJl4/NAkqHeuGKNy5djkJgUhewihTaPz9K66trJfUQ1BDW+DaBAyY+kp1RSC S12ED/zPCIVlvHtc9EP/2BGw6NmQNiwmq9TPTJD49SZd+qtEsbJeDme+GATK90WN9XQ/ gPLEQ3SZSYulfjyr0WsY1tmklhxK5XnuDCuLz359ZI8g2XpBXuTpYiS3sn9ZlJL5muI5 o2vSSNaLbbalklV9novFSF8qHrJ6vohHrpmryrU9oyOWuaj/0EhHSzzl5/RDUV9eMU0X IFXQ== X-Gm-Message-State: AAQBX9d0aYKptMCArpr+eyHpg13BPY2H32TRwlYitlpygLV02XB6970E WG3EcQ0wLz0EDxrKMRYhdt8= X-Google-Smtp-Source: AKy350Y57lkhGNKGusZTe1Ccjks7RAhfQWTFjJNaeggniN6HY1iRwt0FJlP6A1elPket790ozAS67g== X-Received: by 2002:ad4:5dcb:0:b0:56e:b91f:aec4 with SMTP id m11-20020ad45dcb000000b0056eb91faec4mr3578035qvh.11.1680619615815; Tue, 04 Apr 2023 07:46:55 -0700 (PDT) Received: from maniforge ([24.1.27.177]) by smtp.gmail.com with ESMTPSA id mh10-20020a056214564a00b005dd8b9345d7sm3438042qvb.111.2023.04.04.07.46.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Apr 2023 07:46:55 -0700 (PDT) Date: Tue, 4 Apr 2023 09:46:52 -0500 From: David Vernet To: Alexei Starovoitov Cc: davem@davemloft.net, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, davemarchevsky@meta.com, tj@kernel.org, memxor@gmail.com, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH bpf-next 4/8] bpf: Teach verifier that certain helpers accept NULL pointer. Message-ID: <20230404144652.GA3896@maniforge> References: <20230404045029.82870-1-alexei.starovoitov@gmail.com> <20230404045029.82870-5-alexei.starovoitov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230404045029.82870-5-alexei.starovoitov@gmail.com> User-Agent: Mutt/2.2.10 (2023-03-25) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Apr 03, 2023 at 09:50:25PM -0700, Alexei Starovoitov wrote: > From: Alexei Starovoitov > > bpf_[sk|inode|task|cgrp]_storage_[get|delete]() and bpf_get_socket_cookie() helpers > perform run-time check that sk|inode|task|cgrp pointer != NULL. > Teach verifier about this fact and allow bpf programs to pass > PTR_TO_BTF_ID | PTR_MAYBE_NULL into such helpers. > It will be used in the subsequent patch that will do > bpf_sk_storage_get(.., skb->sk, ...); > Even when 'skb' pointer is trusted the 'sk' pointer may be NULL. > > Signed-off-by: Alexei Starovoitov > --- > kernel/bpf/bpf_cgrp_storage.c | 4 ++-- > kernel/bpf/bpf_inode_storage.c | 4 ++-- > kernel/bpf/bpf_task_storage.c | 8 ++++---- > net/core/bpf_sk_storage.c | 4 ++-- > net/core/filter.c | 2 +- > 5 files changed, 11 insertions(+), 11 deletions(-) > > diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c > index d17d5b694668..d44fe8dd9732 100644 > --- a/kernel/bpf/bpf_cgrp_storage.c > +++ b/kernel/bpf/bpf_cgrp_storage.c > @@ -224,7 +224,7 @@ const struct bpf_func_proto bpf_cgrp_storage_get_proto = { > .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, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &bpf_cgroup_btf_id[0], > .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, > .arg4_type = ARG_ANYTHING, > @@ -235,6 +235,6 @@ const struct bpf_func_proto bpf_cgrp_storage_delete_proto = { > .gpl_only = false, > .ret_type = RET_INTEGER, > .arg1_type = ARG_CONST_MAP_PTR, > - .arg2_type = ARG_PTR_TO_BTF_ID, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &bpf_cgroup_btf_id[0], > }; > diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c > index e17ad581b9be..a4d93df78c75 100644 > --- a/kernel/bpf/bpf_inode_storage.c > +++ b/kernel/bpf/bpf_inode_storage.c > @@ -229,7 +229,7 @@ const struct bpf_func_proto bpf_inode_storage_get_proto = { > .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, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &bpf_inode_storage_btf_ids[0], > .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, > .arg4_type = ARG_ANYTHING, > @@ -240,6 +240,6 @@ const struct bpf_func_proto bpf_inode_storage_delete_proto = { > .gpl_only = false, > .ret_type = RET_INTEGER, > .arg1_type = ARG_CONST_MAP_PTR, > - .arg2_type = ARG_PTR_TO_BTF_ID, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &bpf_inode_storage_btf_ids[0], > }; > diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c > index d1af0c8f9ce4..adf6dfe0ba68 100644 > --- a/kernel/bpf/bpf_task_storage.c > +++ b/kernel/bpf/bpf_task_storage.c > @@ -338,7 +338,7 @@ const struct bpf_func_proto bpf_task_storage_get_recur_proto = { > .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, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], > .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, > .arg4_type = ARG_ANYTHING, > @@ -349,7 +349,7 @@ const struct bpf_func_proto bpf_task_storage_get_proto = { > .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, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], > .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, > .arg4_type = ARG_ANYTHING, > @@ -360,7 +360,7 @@ const struct bpf_func_proto bpf_task_storage_delete_recur_proto = { > .gpl_only = false, > .ret_type = RET_INTEGER, > .arg1_type = ARG_CONST_MAP_PTR, > - .arg2_type = ARG_PTR_TO_BTF_ID, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], > }; > > @@ -369,6 +369,6 @@ const struct bpf_func_proto bpf_task_storage_delete_proto = { > .gpl_only = false, > .ret_type = RET_INTEGER, > .arg1_type = ARG_CONST_MAP_PTR, > - .arg2_type = ARG_PTR_TO_BTF_ID, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], > }; > diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c > index 085025c7130a..d4172534dfa8 100644 > --- a/net/core/bpf_sk_storage.c > +++ b/net/core/bpf_sk_storage.c > @@ -412,7 +412,7 @@ const struct bpf_func_proto bpf_sk_storage_get_tracing_proto = { > .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, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], > .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, > .arg4_type = ARG_ANYTHING, > @@ -424,7 +424,7 @@ const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto = { > .gpl_only = false, > .ret_type = RET_INTEGER, > .arg1_type = ARG_CONST_MAP_PTR, > - .arg2_type = ARG_PTR_TO_BTF_ID, > + .arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL, > .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], > .allowed = bpf_sk_storage_tracing_allowed, > }; Should we also add PTR_MAYBE_NULL to the ARG_PTR_TO_BTF_ID_SOCK_COMMON arg in bpf_sk_storage_get_proto and bpf_sk_storage_delete_proto? > diff --git a/net/core/filter.c b/net/core/filter.c > index 1f2abf0f60e6..727c5269867d 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -4998,7 +4998,7 @@ const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = { > .func = bpf_get_socket_ptr_cookie, > .gpl_only = false, > .ret_type = RET_INTEGER, > - .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, > + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON | PTR_MAYBE_NULL, > }; > > BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx) > -- > 2.34.1 >