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=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT autolearn=ham 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 6E8AFC282C4 for ; Mon, 4 Feb 2019 20:27:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 367BB2073D for ; Mon, 4 Feb 2019 20:27:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vbsthVoO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729240AbfBDU1U (ORCPT ); Mon, 4 Feb 2019 15:27:20 -0500 Received: from mail-wm1-f41.google.com ([209.85.128.41]:54313 "EHLO mail-wm1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728864AbfBDU1U (ORCPT ); Mon, 4 Feb 2019 15:27:20 -0500 Received: by mail-wm1-f41.google.com with SMTP id a62so1293852wmh.4 for ; Mon, 04 Feb 2019 12:27:19 -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:mime-version:content-disposition :user-agent; bh=bz4JbNJnEOGM0ZEeO/rNAutvM5cuFXFUGyB7HbtjIsI=; b=vbsthVoOU3Xc6S0aBF+qRVcrUZ6iMclKkaPXVcXtlVoBB0+amREUKdmTb3tH9ov8e3 xNTzg5wG5F1H5/MCvSwEO4wCSEAm1yStUhdmJ+p2DD8/HogCwCKNXcDAVIs9IvkytK5H yirmgAx0X+4ID77ZPGQe4B+gcrfcTTgv6Fdpf2gEWV8rQ3lt++CXbgN6GqSiM1Mo4CgU dUx8z955RRTATDtV9WADgOzJKZQEmd98B28OZsq3lylHGy4EkHWjqAAvTlPotiOr76IF lJVgKnfMxPFC8ntwz6KaNSbjqccNARuB//9Y1JuH6G0yzLTaiGuZyKu8hC8YqqWuiLB9 7dVw== 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:mime-version :content-disposition:user-agent; bh=bz4JbNJnEOGM0ZEeO/rNAutvM5cuFXFUGyB7HbtjIsI=; b=VYgaybbwL4TTZn4v/X94UIQWaSYyno2zBDTJbj6ffKrt2y4e/Qjd6y4UIhn+OZ/Zxn d0i7FtyGk+8nAWd9puxIY90zFnP/eIpFbsYVvy+lNymLdplTCnYXWMyVbpDN1ejakPWo kFhbeqReh7ssc29Fn4F/5uAdHLufp5Fv7VYnBuXUhcf0D+f18x9JKHiX6As3QwFeppG+ 0eSjKV545U8XSdaYjcYlAjsFMAu7vEco0f2lAVhGDECU1owqZRx01w4jToCPgYVubEUU Vx+YCmkUfzOd0yHXc+my1li5golMnPKDfTMjsE6HTz2pfafq0pC436hfysNYCMvMe0lJ RZWQ== X-Gm-Message-State: AHQUAubTgeU7fvi504l5NbwgxqytGMCRAmy1KMhg0gcbuO4PKR2tFC31 V6UyqcuFh2X1EwD/KwH8oNfRt68= X-Google-Smtp-Source: AHgI3Ib37Rinzi4si1SLI57PYKsDoca6FdWSldQcaoefPCjDi6ahudOUXllaotn2uXrGNZhTgtt45w== X-Received: by 2002:a7b:c191:: with SMTP id y17mr865706wmi.60.1549312038321; Mon, 04 Feb 2019 12:27:18 -0800 (PST) Received: from avx2 ([46.53.245.13]) by smtp.gmail.com with ESMTPSA id n15sm9496995wrt.21.2019.02.04.12.27.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Feb 2019 12:27:17 -0800 (PST) Date: Mon, 4 Feb 2019 23:27:15 +0300 From: Alexey Dobriyan To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH 1/4] elf: don't be afraid of overflow Message-ID: <20190204202715.GA27482@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Number of ELF program headers is 16-bit by spec, so total size comfortably fits into "unsigned int". Space savings: 7 bytes! add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-7 (-7) Function old new delta load_elf_phdrs 137 130 -7 Signed-off-by: Alexey Dobriyan --- fs/binfmt_elf.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -418,8 +418,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex, struct file *elf_file) { struct elf_phdr *elf_phdata = NULL; - int retval, size, err = -1; + int retval, err = -1; loff_t pos = elf_ex->e_phoff; + unsigned int size; /* * If the size of this structure has changed, then punt, since @@ -429,13 +430,9 @@ static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex, goto out; /* Sanity check the number of program headers... */ - if (elf_ex->e_phnum < 1 || - elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr)) - goto out; - /* ...and their total size. */ size = sizeof(struct elf_phdr) * elf_ex->e_phnum; - if (size > ELF_MIN_ALIGN) + if (size == 0 || size > 65536 || size > ELF_MIN_ALIGN) goto out; elf_phdata = kmalloc(size, GFP_KERNEL);