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 E1CC1ECAAA1 for ; Fri, 9 Sep 2022 17:19:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230490AbiIIRTq (ORCPT ); Fri, 9 Sep 2022 13:19:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229862AbiIIRTo (ORCPT ); Fri, 9 Sep 2022 13:19:44 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA506255B5 for ; Fri, 9 Sep 2022 10:19:41 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id o1-20020a170902d4c100b00177f59a9889so1648317plg.13 for ; Fri, 09 Sep 2022 10:19:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date; bh=y+S5AbIHCrepBfZ2rw1p2j+yX8LnWjY6X4hW/K5B26E=; b=FBPCZrVg3A5xkX2OTUS/Lt5/hDbXEhiQzndmF1GMlIGtCP4Bd8a13tQ+23xzbZ0ced v4ss1uefZSpho+Io18qZ+Q7r9x2x9Ef9TtZDBqgdSJT71TiOHKxQ/E5cuNX5/e0ytcrZ 6hVEESy8F2bpVXFdLh9X3uCCGCdxvW6hZeK58BRWrYrlp/4dEwNxq/KN+sUvaAEY/pXI CaDnNMgVJzv6jcv674hbQp69SmAcCHSU4Wg615K+yZaI3vOsYdNVNtZGFstnWjB2YnFF wrg7EdS6+aH++GFOG0YRUFiWMFi48S1xF1bfJ9aIvTpirymw0rb4fI/mwkCtE1SNIS8U JMpA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date; bh=y+S5AbIHCrepBfZ2rw1p2j+yX8LnWjY6X4hW/K5B26E=; b=xUvsqJLUexsFc3gKIFNnq6TTU3rLAGVFGN17oOWbIuk0xLxnI8stN0ErIRnc1enBxo udwfyMzAVdvWt6uT/MelW/Y4EGe4+P22PVt/MVEziNeM9T+mRxvDMvqHffVlqfo0AMAd Pq1sYWGasL9Yz1EbabXWruDTqHBzl/48osuoCAwKlyIJquITgEsaJqTjYPze6Sy1RFZv wNssavbYTO0H4PoGfJZEjfyMvOtVqbfIogJl+E01Dj69bZgX4QgD012GJkFwWzwz7EBM BxGatm1LT53sWZeljhT4iyweaC0DGDVB6Peysa7YABWUpzwKqZN+sHZxseiJDkW6JcWr 6agA== X-Gm-Message-State: ACgBeo2Zy1Lhb0XPKbYVVkx6RCpYUsGSnoj94u0uuBEYbBEEhIzMV+Oy 66qkRLcdYVqtjzQePKw1vdhvcXo= X-Google-Smtp-Source: AA6agR6QPX7Uuhl63LLM4hwCHcUgMnHrqQo6D5F1r53w/VYF+DHyPdIuNsRFMuyb9aQzk4M/e7lw57I= X-Received: from sdf.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5935]) (user=sdf job=sendgmr) by 2002:a17:90b:10a:b0:200:2849:235f with SMTP id p10-20020a17090b010a00b002002849235fmr202016pjz.1.1662743980876; Fri, 09 Sep 2022 10:19:40 -0700 (PDT) Date: Fri, 9 Sep 2022 10:19:39 -0700 In-Reply-To: <20220909092107.3035-1-oss@lmb.io> Mime-Version: 1.0 References: <20220909092107.3035-1-oss@lmb.io> Message-ID: Subject: Re: [PATCH bpf] bpf: btf: fix truncated last_member_type_id in btf_struct_resolve From: sdf@google.com To: Lorenz Bauer Cc: Martin KaFai Lau , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Song Liu , Yonghong Song , John Fastabend , KP Singh , Hao Luo , Jiri Olsa , bpf@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 09/09, Lorenz Bauer wrote: > When trying to finish resolving a struct member, btf_struct_resolve > saves the member type id in a u16 temporary variable. This truncates > the 32 bit type id value if it exceeds UINT16_MAX. > As a result, structs that have members with type ids > UINT16_MAX and > which need resolution will fail with a message like this: > [67414] STRUCT ff_device size=120 vlen=12 > effect_owners type_id=67434 bits_offset=960 Member exceeds > struct_size > Fix this by changing the type of last_member_type_id to u32. Makes sense to me; I'm surprised the compiler isn't raising a warning on line: last_member_type_id = last_member->type; Reviewed-by: Stanislav Fomichev > Fixes: eb3f595dab40 ("bpf: btf: Validate type reference") > Signed-off-by: Lorenz Bauer > --- > kernel/bpf/btf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 7e64447659f3..36fd4b509294 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -3128,7 +3128,7 @@ static int btf_struct_resolve(struct > btf_verifier_env *env, > if (v->next_member) { > const struct btf_type *last_member_type; > const struct btf_member *last_member; > - u16 last_member_type_id; > + u32 last_member_type_id; > last_member = btf_type_member(v->t) + v->next_member - 1; > last_member_type_id = last_member->type; > -- > 2.34.1