From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-il1-x131.google.com (mail-il1-x131.google.com [IPv6:2607:f8b0:4864:20::131]) by sourceware.org (Postfix) with ESMTPS id 7FE213857709 for ; Mon, 4 Sep 2023 12:32:24 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 7FE213857709 Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=arista.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=arista.com Received: by mail-il1-x131.google.com with SMTP id e9e14a558f8ab-34b0f3b792dso4955525ab.3 for ; Mon, 04 Sep 2023 05:32:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; t=1693830743; x=1694435543; darn=sourceware.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=IF+ZY1QUi9stSqvEUoTEUjDSnRdKZu/sn/61XW61Hm8=; b=ifWzGFjKYSTWctr0NHy+JFmWjGbfC3gq6PqxcuyNgQjUN4nkSsK6KVZC2alpDmP0/h G0uAUUPpOuvB+E5GHxTAsK6DlTAwn7SMMx/FQvOzZVDNoqsxEpAag/OvIsg3KdOMr5tf qnp3LCsmxnDT95crBjkplqYhmyCsXjT3vLWfW0tSfcmGJwQge7v+IQzaC4UWiYkyj09m Kf2c4dYaswuYC/CjGJYdSiCXBhwkZRJ//wXCeKtrWhNImIUa/aa2c4j4IrnYt+xRDSMr Z3HUd2+9Gui8wMFQwcb2WJFedp2nwD5eR4mUzNWRxTcRGxgeDHR5v3Vui6IU+3HNSDL9 CDhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693830743; x=1694435543; 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=IF+ZY1QUi9stSqvEUoTEUjDSnRdKZu/sn/61XW61Hm8=; b=Pm+wXMWhz7NgxlK6BVs26hHSZO+dPqJ4JwnzoXm8DruT/PlLzzzt9wg5SRH4MF1fuy LH2S55XoOKyHXoV2OlbcsFaHQ/tNC8y71xpdEoBs7E7AhCEpIFW0hcgQHLOF8qtWyh+2 0POH21K97+GI1b3FOWw1WMuAqBLXgc0IBTt6U1A8O+LxdLjIBE/D17JcS9KBf3BVathP xTXW/Og0XcH0S9OeqpefNqOQwc9C6m2E6ubUyWczF3TgUA9VoQZLYo7IsnKupvdX9PFx qICFTQvo1oXU4rTbke8QNMGQub66UsZ6bHtrivT3W7l6svZWsO0Dpa515axHvRf813bn HG5Q== X-Gm-Message-State: AOJu0YxLQqE+CwQ5iZDpflYE0X3kwc5sNJzS7dijhWL3wPLy8nbTubvT uZtWieJgSgwDHkbzB1DAS6xZ+XGt2DcVzOaKmD1PSQ== X-Google-Smtp-Source: AGHT+IGJZ+ZyALhemm35YKh+6u1UgE0BuStD1Gv6MDiZcGNz0jrquMhHxAnHboRK7gbwY1SgUm2Ki9IPIgOxP0UwDr4= X-Received: by 2002:a05:6e02:219c:b0:34e:1f27:2e5d with SMTP id j28-20020a056e02219c00b0034e1f272e5dmr6917073ila.14.1693830743737; Mon, 04 Sep 2023 05:32:23 -0700 (PDT) MIME-Version: 1.0 References: <20230904105427.283848-1-peadar@arista.com> In-Reply-To: From: Peter Edwards Date: Mon, 4 Sep 2023 13:32:12 +0100 Message-ID: Subject: Re: [PATCH] elf: Avoid pointer-arithmetic underflow in ldconfig To: Andreas Schwab Cc: Peter Edwards via Libc-alpha Content-Type: multipart/alternative; boundary="000000000000ca7249060487b3a9" X-Spam-Status: No, score=-3.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,HTML_MESSAGE,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: --000000000000ca7249060487b3a9 Content-Type: text/plain; charset="UTF-8" On Mon, 4 Sept 2023 at 12:18, Andreas Schwab wrote: > > > + loadoff = (uintptr_t)segment->p_vaddr - > > + (uintptr_t)segment->p_offset; > > Shouldn't that use a signed difference, then? Since loadoff is now > ptrdiff_t, I would expect the use of ptrdiff_t for the casts. > Hi, For the 32-bit code, we were previously relying on the behaviour of wrap-around on the unsigned type, this just extends that reliance to a pointer-sized integer on the 64 bit platform. I guess intptr_t might be a better option than uintptr_t? I would think ptrdiff_t would really only be useful as the difference between two pointers (and I guess if you want to be pedantic, might not always be the same as the size of a pointer). --000000000000ca7249060487b3a9--