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 4239FC4332F for ; Fri, 4 Nov 2022 21:56:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229689AbiKDV44 (ORCPT ); Fri, 4 Nov 2022 17:56:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229544AbiKDV4z (ORCPT ); Fri, 4 Nov 2022 17:56:55 -0400 Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF71359FCB; Fri, 4 Nov 2022 14:56:54 -0700 (PDT) Received: by mail-ej1-x636.google.com with SMTP id y14so16619863ejd.9; Fri, 04 Nov 2022 14:56:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=4lxURksHj3T3+DcMA1c6SDe+tyv9on8orkNxxpF1wpw=; b=l0krgcQ1x+QyVprsYS3e+Ksm4+O/J8WaR2uV6+jmasJviwEA3s2GkMc63/xsHLjn7v ixmrS6jsmrwUnuUdjE8GWaqkURtfAIBNCCDsOAH5yvj37AORMKhnXUlwGDLLishrkEap hrZHKLTqYnAaRNKiwshxZEHjqjx5LSXqF3INh9C2ED0eTg/NncG5b8HIHoQNzr8f7MXo lpHeaInkAo6UuVIdtSENIfi06o7QZxPQNsBAr4SfuN6j4EXeoA9ICcz0/c7FLMEIYK+3 khdW04Rm0KbzqigAluLFYkZG4vif9LQdMRDGfoQzFNW3uBAQJcLVelIpU8Z9vNHcFGmw F7PQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=4lxURksHj3T3+DcMA1c6SDe+tyv9on8orkNxxpF1wpw=; b=s19UwLSENXQF4FoGFDrZAFymyExVHsZAmUN4XTI773aInZYFTxQF/RDCKBTat9Cn+P k11B2wrQmZIIeRLSPy4FLiEf0Emvv1BO1du9cEFAqc/ojJ5jl8No5bjx2I5NOTXFSlTJ 8AH/rGPZnB6oDpOe8YAxqTu6zKi+CQxlQy8/o7mnaq5n3vNd2I78orw8+/NkK1Ix949/ izf4xzQTjeR58LkDXOXPmIm1/Gk2l05QzQv5rBFbUeDc+5ylbp1dFCQzeoRIKkaYUtSY QiX3sS5FcJLQZu4SDXXiVMOFeYzaMknyautP/1NiKIHNUqtI3PWShAU/moV6o0VYsNxL lRng== X-Gm-Message-State: ACrzQf1ZwHhwXxnp6Q5066fm+1XrYgMNHqkm8GQEO3mayw3q+yTltVK0 W/pA5HuDtucEMu78IXEwcvCfFvnUfet1+1MB9OI= X-Google-Smtp-Source: AMsMyM7L6eNb0nhcMUMgqoe134AW/LDinI4BWgMVWvwPF3qBv3jLgKkauI5+9B9OECRCQCMH3pk11ofWlwIrl3aIwno= X-Received: by 2002:a17:906:11d6:b0:7ad:fd3e:2a01 with SMTP id o22-20020a17090611d600b007adfd3e2a01mr17227919eja.545.1667599013262; Fri, 04 Nov 2022 14:56:53 -0700 (PDT) MIME-Version: 1.0 References: <20221103083254.237646-1-yangjihong1@huawei.com> <20221103083254.237646-3-yangjihong1@huawei.com> In-Reply-To: <20221103083254.237646-3-yangjihong1@huawei.com> From: Andrii Nakryiko Date: Fri, 4 Nov 2022 14:56:40 -0700 Message-ID: Subject: Re: [PATCH 2/4] bpf: Remove size check for sk in bpf_skb_is_valid_access for 32-bit architecture To: Yang Jihong Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, illusionist.neo@gmail.com, linux@armlinux.org.uk, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, mykolal@fb.com, shuah@kernel.org, benjamin.tissoires@redhat.com, memxor@gmail.com, delyank@fb.com, asavkov@redhat.com, colin.i.king@gmail.com, bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Thu, Nov 3, 2022 at 1:36 AM Yang Jihong wrote: > > The error code -EACCES is returned when bpf prog is tested in 32-bit environment, > This is because bpf_object__relocate modifies the instruction to change memory > size to 4 bytes, as shown in the following messages: > > libbpf: prog 'kfunc_call_test1': relo #2: matching candidate #0 [18342] struct __sk_buff.sk (0:30:0 @ offset 168) > libbpf: prog 'kfunc_call_test1': relo #2: patched insn #1 (LDX/ST/STX) off 168 -> 168 > libbpf: prog 'kfunc_call_test1': relo #2: patched insn #1 (LDX/ST/STX) mem_sz 8 -> 4 > > As a result, the bpf_skb_is_valid_access check fails. For 32-bit architecture, > unnecessary checks need to be deleted. > > Signed-off-by: Yang Jihong > --- > net/core/filter.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/net/core/filter.c b/net/core/filter.c > index bb0136e7a8e4..eab7ce89740c 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -8269,8 +8269,6 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type > return false; > break; > case offsetof(struct __sk_buff, sk): > - if (type == BPF_WRITE || size != sizeof(__u64)) > - return false; this probably should be specific to host architecture bitness? I'd imagine that size = 4 should be invalid on 64-bit arches (reading half of the pointer is bad) either way, please make sure to add tests specifically for this case in test_verifier > info->reg_type = PTR_TO_SOCK_COMMON_OR_NULL; > break; > case offsetof(struct __sk_buff, tstamp_type): > -- > 2.30.GIT >