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 3DF7BEB64DA for ; Wed, 19 Jul 2023 07:09:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229542AbjGSHJS (ORCPT ); Wed, 19 Jul 2023 03:09:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229535AbjGSHJR (ORCPT ); Wed, 19 Jul 2023 03:09:17 -0400 Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E49D3E47 for ; Wed, 19 Jul 2023 00:09:15 -0700 (PDT) Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-3fbea14706eso60352065e9.2 for ; Wed, 19 Jul 2023 00:09:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent.com; s=google; t=1689750554; x=1692342554; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=AnRQdh3EEqJvpxETy5ODliVLYVhTAipKqSwZ1tgyM7s=; b=aTwmtP37x0bkdUYFbjUqUYnJC/Hnr+D9La8jEgyiierVL4utIhqhD1JTy+P+f+y/mq UXKokW7pEV5meRgolDZSxJ7N19/4DmWjiMeVcvYTPDLdjlidkQUIu6fATD7bXgYsUi5+ QDsDb68YKoRkNiyCH5mzvEE+uIsQvdaHoFtI5FrxdLVyaP/VsEGlxadzIdv39txlqr8M ZmOPhQxhoDjonu4G4cLR6BjLvY5eh7gwcdHL91j5C314qlUhimptswBFolJ9CVmGacBk Ml8ckDptZTszCTHgyoEHGqJ2lzHA0ZRe9xh4tuA8rIrFHESi3UpHfTen3XB+x58nc/YG JJOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689750554; x=1692342554; h=in-reply-to:content-transfer-encoding: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=AnRQdh3EEqJvpxETy5ODliVLYVhTAipKqSwZ1tgyM7s=; b=PH5AY3P8h8pqDTVNoUHun72IBv24gUte9Up820YRyrMjjyXbJxdhgM1CrTEqmir8Ux q/mtMt8OLkqiLWbWW8lbgKU4cSbmhyaTaOlSmfjeW4kdzPGPr4mBIDlhcKhaPEESA/du NElyl2Z/Sx8dCyeJHBDgRHuPLP576HCoepibWwDeZZVqZRAg239UKR8x9mggz1h5cprD 9uIPOFxDcdDNmoi3LCiyV2BbOsglUoYPrerSADvyDTgWL1Jyc6zJqSBc2zKbVDW/FlYN SlIqsWFrkZ8NJPZsPrkDIUzvnJtkhKXc5T5B+UJ+pkYswKJGkA3DyTiixv0yfVP7n+/D CJYg== X-Gm-Message-State: ABy/qLa/TAwnz00LQrzm8lgw1jFZXDWOelq6cULWRHEZUFIknTMZalSG /7JzwTm5+yunlGvQFFRDHml+Pg== X-Google-Smtp-Source: APBJJlEHxNQB8OI0gK1JkgrcA6qpKfCt1495gUus2SsESAJnzz3dh8IXIELLzNbEHSWbTsk9l2XGjg== X-Received: by 2002:adf:f48f:0:b0:315:adee:2e47 with SMTP id l15-20020adff48f000000b00315adee2e47mr14943637wro.30.1689750554376; Wed, 19 Jul 2023 00:09:14 -0700 (PDT) Received: from zh-lab-node-5 ([2a02:168:f656:0:1ac0:4dff:fe0f:3782]) by smtp.gmail.com with ESMTPSA id n4-20020a5d4204000000b00315a1c160casm4388505wrq.99.2023.07.19.00.09.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 Jul 2023 00:09:13 -0700 (PDT) Date: Wed, 19 Jul 2023 07:10:23 +0000 From: Anton Protopopov To: Alexei Starovoitov Cc: Martin KaFai Lau , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , Hou Tao , Joe Stringer , bpf , LKML , "open list:KERNEL SELFTEST FRAMEWORK" Subject: Re: [PATCH bpf-next 1/3] bpf: consider CONST_PTR_TO_MAP as trusted pointer to struct bpf_map Message-ID: References: <20230714141747.41560-1-aspsk@isovalent.com> <20230714142100.42265-1-aspsk@isovalent.com> <20230714142100.42265-2-aspsk@isovalent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Tue, Jul 18, 2023 at 05:54:27PM -0700, Alexei Starovoitov wrote: > On Sun, Jul 16, 2023 at 12:49 AM Anton Protopopov wrote: > > > > On Fri, Jul 14, 2023 at 10:56:00AM -0700, Alexei Starovoitov wrote: > > > On Fri, Jul 14, 2023 at 7:20 AM Anton Protopopov wrote: > > > > > > > > Patch verifier to regard values of type CONST_PTR_TO_MAP as trusted > > > > pointers to struct bpf_map. This allows kfuncs to work with `struct > > > > bpf_map *` arguments. > > > > > > > > Save some bytes by defining btf_bpf_map_id as BTF_ID_LIST_GLOBAL_SINGLE > > > > (which is u32[1]), not as BTF_ID_LIST (which is u32[64]). > > > > > > > > Signed-off-by: Anton Protopopov > > > > --- > > > > include/linux/btf_ids.h | 1 + > > > > kernel/bpf/map_iter.c | 3 +-- > > > > kernel/bpf/verifier.c | 5 ++++- > > > > 3 files changed, 6 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h > > > > index 00950cc03bff..a3462a9b8e18 100644 > > > > --- a/include/linux/btf_ids.h > > > > +++ b/include/linux/btf_ids.h > > > > @@ -267,5 +267,6 @@ MAX_BTF_TRACING_TYPE, > > > > extern u32 btf_tracing_ids[]; > > > > extern u32 bpf_cgroup_btf_id[]; > > > > extern u32 bpf_local_storage_map_btf_id[]; > > > > +extern u32 btf_bpf_map_id[]; > > > > > > > > #endif > > > > diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c > > > > index d06d3b7150e5..b67996147895 100644 > > > > --- a/kernel/bpf/map_iter.c > > > > +++ b/kernel/bpf/map_iter.c > > > > @@ -78,8 +78,7 @@ static const struct seq_operations bpf_map_seq_ops = { > > > > .show = bpf_map_seq_show, > > > > }; > > > > > > > > -BTF_ID_LIST(btf_bpf_map_id) > > > > -BTF_ID(struct, bpf_map) > > > > +BTF_ID_LIST_GLOBAL_SINGLE(btf_bpf_map_id, struct, bpf_map) > > > > > > > > static const struct bpf_iter_seq_info bpf_map_seq_info = { > > > > .seq_ops = &bpf_map_seq_ops, > > > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > > > > index 0b9da95331d7..5663f97ef292 100644 > > > > --- a/kernel/bpf/verifier.c > > > > +++ b/kernel/bpf/verifier.c > > > > @@ -5419,6 +5419,9 @@ static bool is_trusted_reg(const struct bpf_reg_state *reg) > > > > if (reg->ref_obj_id) > > > > return true; > > > > > > > > + if (reg->type == CONST_PTR_TO_MAP) > > > > + return true; > > > > + > > > > > > Overall it looks great. > > > Instead of above, how about the following instead: > > > > > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > > > index 0b9da95331d7..cd08167dc347 100644 > > > --- a/kernel/bpf/verifier.c > > > +++ b/kernel/bpf/verifier.c > > > @@ -10775,7 +10775,7 @@ static int check_kfunc_args(struct > > > bpf_verifier_env *env, struct bpf_kfunc_call_ > > > if (!is_kfunc_trusted_args(meta) && !is_kfunc_rcu(meta)) > > > break; > > > > > > - if (!is_trusted_reg(reg)) { > > > + if (!is_trusted_reg(reg) && > > > !reg2btf_ids[base_type(reg->type)]) { > > > > > > > > > This way we won't need to list every convertible type in is_trusted_reg. > > > > > > I'm a bit hesitant to put reg2btf_ids[] check directly into is_trusted_reg(). > > > Maybe it's ok, but it needs more analysis. > > > > I am not sure I see a difference in adding a check you proposed above and > > adding the reg2btf_ids[] check directly into the is_trusted_reg() function. > > Basically, we say "if type is in reg2btf_ids[], then consider it trusted" in > > both cases. AFAIS, currently the reg2btf_ids[] contains only trusted types, > > however, could it happen that we add a non-trusted type there? > > > > So, I would leave the patch as is (which also makes sense because the > > const-ptr-to-map is a special case), or add the "reg2btf_ids[] check" > > directly into the is_trusted_reg() function. > > Fair enough. Let's add reg2btf_ids[] to is_trusted_reg() directly. Thanks, I will send v2.