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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3490FC3DA4A for ; Sat, 27 Jul 2024 00:31:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 842EF6B0083; Fri, 26 Jul 2024 20:31:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7F1D86B0088; Fri, 26 Jul 2024 20:31:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6B9DA6B0089; Fri, 26 Jul 2024 20:31:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 4D1966B0083 for ; Fri, 26 Jul 2024 20:31:00 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id A3988A0170 for ; Sat, 27 Jul 2024 00:30:59 +0000 (UTC) X-FDA: 82383652638.17.A5B952F Received: from mail-pg1-f182.google.com (mail-pg1-f182.google.com [209.85.215.182]) by imf28.hostedemail.com (Postfix) with ESMTP id B1ACDC001B for ; Sat, 27 Jul 2024 00:30:57 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=L1xbjl0h; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf28.hostedemail.com: domain of andrii.nakryiko@gmail.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=andrii.nakryiko@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1722040201; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=StO8kndJTQRbnIGG3lvbO55jDVCGSi6tPsTcTxq7VYM=; b=jf4WIVLa2ySavmHeOH8oGmJBoLYzoUZhULn65JR4JBlbsVNhNWKdroiAybbm9f/857TKXM aOD2VPZc98ubX1P/YjSgdBfkIQyHzKSUEC/iuK790EsHOk2Vo/JoegVTLU5mzDUL7lwCc3 0c/78wowTJWBiYfuKVnEzD/fZbC/SZA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1722040201; a=rsa-sha256; cv=none; b=IXHxlp0/CPzCxnVZVHTmWr5Ji9s0CfoEcdM74ER9UVca+oFCgSA5fOM/yZce+tRneJhQu6 HDCOAyvwnc/W/RB7QHoY9tVRIDMZRVjXk/9u+2S/BJeJ9N5w/R7nEvr0k7QWJDl3GaIo1f p1fR0ZPg5M26smYclcBth8eV7xdr58A= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=L1xbjl0h; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf28.hostedemail.com: domain of andrii.nakryiko@gmail.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=andrii.nakryiko@gmail.com Received: by mail-pg1-f182.google.com with SMTP id 41be03b00d2f7-656d8b346d2so1022716a12.2 for ; Fri, 26 Jul 2024 17:30:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722040256; x=1722645056; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=StO8kndJTQRbnIGG3lvbO55jDVCGSi6tPsTcTxq7VYM=; b=L1xbjl0h84Z3sB3bnBzGtyMY/IQoct6gIsJqDotKS1gr61xn+O3amFTKPLs3DTIrZH +4XrnlD5YvtP3UJP57VUREUbVDojG/b3Ws6NH0j66vI3wOndD04DJDEjAX40EEXG6iEA VIPdkXfC8xfyCGd52/Fi9x0DT9S1c4AyO7sSj3TFqDaozgMUQjHQirfsPdzPvEd7L44X aDNh2OfWk2wRwOD+zYd7TUaBW3oWzzO6xXvBE5Nx8u2DL35YKkTBPcGLtDrQ5cd7bKuN bCxu6ZTRzO4xrG5cLUzp96x7QsP0F4PWxUk8xRv5zVGcPT3sOmN2k+WJsyV2c71g9AVo sTfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722040256; x=1722645056; h=content-transfer-encoding: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=StO8kndJTQRbnIGG3lvbO55jDVCGSi6tPsTcTxq7VYM=; b=cSDiC49J/HA8+q/ZoW2oLKvujBKrQ2Jhvj+OqPXMcbMICqf95Gi+VlSGLUPeCNoVRt CsGHDN8D1qUZnhxWGNKwpL0+mQCEx0WA1iQMarAf3CTfoL+vSKUeRPkso18Yy2FIz/Ns I9jPdYXRuWNmDdNpayLWKkVkZGl3fy8dtVd0URtHj/lUgoHf/J+yNabRX5JlUZV0xhfS ndzHaqTU+0KyUdNr45XmB5sm/RAW/nviAMgTAJaUxdZugV6kj+wAVEzZqE8CqnGhoacY 3V0gVhKMzMjMSDzxzYOSgP3KveOulrQd3QyNIL9r3Y+6lC+D8FkVCqQ4dPuhhcyERMpZ vXEA== X-Forwarded-Encrypted: i=1; AJvYcCXDF1SGJfXejYpA+hDFBelLH/QJ4KPUQzdlKQQziczmlj/Oa31ss2cwGLawPO0/RxvatRyWUgF4N2VeKQr6mEfC6bs= X-Gm-Message-State: AOJu0YwU1jvAhai+ZMIaYgUdUwiRV0lY6lE2qpTYfaAlaAh7e+CP4g4n xbHZwa73FwL8Le12UNZKZbIH3J4THNSTKa6X2nkzPWYcxmiyl1S4p/oiWTabTby0B/VyZ8OtUxP VmvMCK9NUU8+3Kpeqq8cL/S53mQE= X-Google-Smtp-Source: AGHT+IGLyqm9kfSgfKswGpdXMK88MBE/WYwyC4rANzUvflZ9b29D516O8HaFT+eNdp1wRbjLNztIvmIQ3DUYMIqbpEY= X-Received: by 2002:a05:6a20:3d89:b0:1c2:8949:5ba1 with SMTP id adf61e73a8af0-1c4a1529b50mr1123848637.53.1722040256447; Fri, 26 Jul 2024 17:30:56 -0700 (PDT) MIME-Version: 1.0 References: <20240724225210.545423-1-andrii@kernel.org> <20240724225210.545423-3-andrii@kernel.org> In-Reply-To: From: Andrii Nakryiko Date: Fri, 26 Jul 2024 17:30:44 -0700 Message-ID: Subject: Re: [PATCH v2 bpf-next 02/10] lib/buildid: take into account e_phoff when fetching program headers To: Andi Kleen Cc: Andrii Nakryiko , bpf@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, adobriyan@gmail.com, shakeel.butt@linux.dev, hannes@cmpxchg.org, osandov@osandov.com, song@kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B1ACDC001B X-Stat-Signature: qk64htupn7unurx9g9d98xoonnrskyjr X-Rspam-User: X-HE-Tag: 1722040257-567233 X-HE-Meta: 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 uWpzEdwJ bUKR6uLRm7TU4oUNeA1LglYOkrxUG061EGG0Wtzc/MmbHJC/Wrrkkdtm549ybTGdbbpJwQ9KQn/LvPJg2nhEFV2wxPPwb/aaj+toP8LuTLDdiI5ahxwYym45i9dwxj4wFvLjfJmHu2c6lWAA0LDXDByVbjS12JQld/TT3R6NOHWjVgHPGnGRk08HBkuTNbKW2b+UbExSkVD4TO+iWMR5ZsVyQ56l04IlmwR6wJAGMyFRXNoApLXeD1HdUj197IMm/fMB8oq0L9HyRxb9GKhRlJ5hOVYZJ9a7wcKjywoQ5jBtfD2vzVDSIr07pDf2FNLmaq7y9kRN0WPM1E0/oPR2TxD5Ph9yWt0e62KTw3k9y2xT5O8J0Qah4bBQlcF/qqAOWJDDqFgLwVTMesis= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000052, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jul 25, 2024 at 3:45=E2=80=AFPM Andi Kleen wro= te: > > > @@ -214,13 +214,14 @@ static int get_build_id_32(struct freader *r, uns= igned char *build_id, __u32 *si > > > > /* subsequent freader_fetch() calls invalidate pointers, so remem= ber locally */ > > phnum =3D ehdr->e_phnum; > > + phoff =3D READ_ONCE(ehdr->e_phoff); > > > > /* only supports phdr that fits in one page */ > > if (phnum > (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)= ) > > return -EINVAL; > > > > for (i =3D 0; i < phnum; ++i) { > > - phdr =3D freader_fetch(r, i * sizeof(Elf32_Phdr), sizeof(= Elf32_Phdr)); > > + phdr =3D freader_fetch(r, phoff + i * sizeof(Elf32_Phdr),= sizeof(Elf32_Phdr)); > > What happens if phoff is big enough that this computation wraps? > phoff is u32, phoff + i * sizeof(Elf32_Phdr) will be casted to u64 as it's passed into freader_fetch (which expects u64), and so it will be an offset slightly bigger than 4GB into the file. If that happens to be a valid file offset, so be it, we'll fetch the page at that file offset. If not, freader_fetch() will return NULL.