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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91F1BC3F2D1 for ; Wed, 4 Mar 2020 00:03:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6446C206D5 for ; Wed, 4 Mar 2020 00:03:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Wtdw/bpD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727823AbgCDADc (ORCPT ); Tue, 3 Mar 2020 19:03:32 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:42590 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727604AbgCDADb (ORCPT ); Tue, 3 Mar 2020 19:03:31 -0500 Received: by mail-pg1-f196.google.com with SMTP id h8so72285pgs.9; Tue, 03 Mar 2020 16:03:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Cg+Bk6p3ng/oCqeB9jAP5HpcQ6wBIVVyIyzT0MMNq0k=; b=Wtdw/bpDAHegTWVPqPiInwTRdc+XxDNKZV5OyxUdLlV7JnWYcKCYo5WwcOqZBwoZgR lCMRDanCykEaZjdNDLpO9T5CqO7BcZg7jnRfbK4HKgL0nmUTQbR2CSv9dU3LQrWdftHN Ok2JGkqTvgMzihWyEv4rDsCvtgunV7D2BpPu2+FdHSA61Fo2ozHR7we/hDStKntnGNU3 yTaKQw5sIuR7Mb+sPgJue9DY26rhlMPuqGcVxhT3opQ9hKRVyjtmJ3Za+jzdRN06xyaY 5raGwMxS83abexPR9tjLNaRRvARn3H7mJcJfNYoQCe0IT9YYvseds7bNeO9X1HksqvWl hFLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Cg+Bk6p3ng/oCqeB9jAP5HpcQ6wBIVVyIyzT0MMNq0k=; b=pkHhtqN1ljR9QQrxQUrQDLnvnDZyfQtO0gCdy1JpjHjVOdKsNhvpuMeAWpg05ImXAS hOHFdB2HTfn1lLI6wGkgAiciYAXpFizqhQ+Z+koarU1Wl3FpDR86/Ae6n4q/49i46JWf VPeDweelFt59hQmtoTF0QPC15+CKPW0hdjS7L+/RxGpjP+FhqwIvICEo0lThUQPgfqNm fh7Awy8vicFbfvvk/W7pyxGkYrcdBO0kL5DmaaznaB522UcBZ/d9Y6bDJg2oi09FT7FG lGNS9PNaqTCFYinPFTR5yKSCdYFFENMuMGZF95WA2Oh5Xx6vBETdgABeC3zzp+xVtciZ or2A== X-Gm-Message-State: ANhLgQ0LINO0jpmCgd+kWaHnkPF9YRnx4AisherIovrOSXhodLW1o7XR ceKpHKi4y50cw6JYu4LfllA= X-Google-Smtp-Source: ADFU+vvLke/PQpWmYNEZBsbhWp2sSTWm813w2K3TO0HseVYhvp+AY3D8KiClhK8qArj0CeTWoS6W/g== X-Received: by 2002:a63:4103:: with SMTP id o3mr5683444pga.199.1583280210838; Tue, 03 Mar 2020 16:03:30 -0800 (PST) Received: from ast-mbp ([2620:10d:c090:500::4:a0de]) by smtp.gmail.com with ESMTPSA id z22sm4937779pgn.19.2020.03.03.16.03.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Mar 2020 16:03:29 -0800 (PST) Date: Tue, 3 Mar 2020 16:03:27 -0800 From: Alexei Starovoitov To: KP Singh Cc: Andrii Nakryiko , open list , bpf , Alexei Starovoitov , Daniel Borkmann , Paul Turner , Florent Revest , Brendan Jackman Subject: Re: [PATCH bpf-next 4/7] bpf: Attachment verification for BPF_MODIFY_RETURN Message-ID: <20200304000326.nk7jmkgxazl3umbh@ast-mbp> References: <20200303140950.6355-1-kpsingh@chromium.org> <20200303140950.6355-5-kpsingh@chromium.org> <20200303232151.GB17103@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200303232151.GB17103@chromium.org> User-Agent: NeoMutt/20180223 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Mar 04, 2020 at 12:21:51AM +0100, KP Singh wrote: > > > > + t = btf_type_skip_modifiers(btf, t->type, NULL); > > > + if (!btf_type_is_int(t)) { > > > > Should the size of int be verified here? E.g., if some function > > returns u8, is that ok for BPF program to return, say, (1<<30) ? > > Would this work? > > if (size != t->size) { > bpf_log(log, > "size accessed = %d should be %d\n", > size, t->size); > return false; > } It will cause spurious failures later when llvm optimizes if (ret & 0xff) into u8 load. I think btf_type_is_int() is enough as-is.