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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8C1C3C27C79 for ; Tue, 18 Jun 2024 01:29:40 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sJNeQ-0007aB-Mz; Mon, 17 Jun 2024 21:28:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sJNeO-0007Zh-VZ for qemu-devel@nongnu.org; Mon, 17 Jun 2024 21:28:44 -0400 Received: from mail-ot1-x332.google.com ([2607:f8b0:4864:20::332]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1sJNeN-0002v7-GZ for qemu-devel@nongnu.org; Mon, 17 Jun 2024 21:28:44 -0400 Received: by mail-ot1-x332.google.com with SMTP id 46e09a7af769-6f9398390fcso1552300a34.3 for ; Mon, 17 Jun 2024 18:28:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1718674122; x=1719278922; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id:from :to:cc:subject:date:message-id:reply-to; bh=CeDHcl8j9GHw3+3IaC2MSqv7jEEamRYynXW/la2DZrc=; b=kx0B+PWUrRnjM0ItV0XW5CTj5lnkdlFrzRtEObHGnvlMagvkBN4+3RPduJ5PAIQ6R2 fM3kjHZEgeDz0CYP+mJhOuQMbZ7L7gGWFdmPCu+iWq0cvjq+CyipWUxkahNa+1eL85Cg QOSGtw3xo3ByLJOkpJGz+T9LE92+dMI7Jf5Ue+ahHmDSTfOmqYm9xTdRQHPSakU6GxsP yHnunyFD6CpHSUGtalREqR/zMZT7l8KutOtVfxW4IunMxXEN1PRJYHCoaLo+h9p1EebB sPsdUp1EFCuIECsrOxS3oX7QH75PdSHWaDN0jaWvm2jEpfkEJXudBI69TUTVXGDzGMHv rj0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718674122; x=1719278922; h=content-transfer-encoding:in-reply-to:from:content-language :references:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=CeDHcl8j9GHw3+3IaC2MSqv7jEEamRYynXW/la2DZrc=; b=thdr+wvoSL/WOhiR+wCgOvzhueOXm0GX8NL8fjNpnDp16hbfEuSxQN8mBBscO4kcE+ HqbyRzPcw+Lseq9W/wwxo5eti3A8W4dnlQqQwHu9hZx1fXaah1auLqqtgYMIHMQcIDAg NSuDlC91I3SXD4CH/YwMEaaLO9th4x24KcGY1qobSw2wwoa3SrYpVxXChE5EM8LKJGlN uHiQi39IZvL4KFIewCWD+n9Njl6GxtPZfqx7pPneYeHE+xHjqQ3QRVt36GTgokizKUsR n5zC5lM/onVTtJdypgm0sv5WAgbKMif7f6GEsSogADxhbzGQyCs+KSSnMp1pSw+vsUlf IISw== X-Forwarded-Encrypted: i=1; AJvYcCVsd3+kXgjnBQhxkqj0NUSHg6D0o7otarELpk7yI4E7+JfikRSi+gS8/1EORXJ7UshKFkLsAMpbtFZdzXMtxsOGv4khwFM= X-Gm-Message-State: AOJu0Yz1BoHKxyLaljtdV+ejIQfpBrPPBuaqp/PLmM7f+rgIgwcg72aQ W5LjpobGdVlR8M6nkRaFTsByXSxM3W9Qs/YoM0ztwZxELTq2mwlDank4KWutCFY= X-Google-Smtp-Source: AGHT+IHCduZIe6Hhm6Bh11w05fcKzGlZm3MVpF3HqEEoyMG3nuZNq3X7jYAF9UlmX8hCcDMU6CBfLA== X-Received: by 2002:a9d:6359:0:b0:6fb:8193:85f3 with SMTP id 46e09a7af769-6fb93b035f7mr11167081a34.29.1718674121879; Mon, 17 Jun 2024 18:28:41 -0700 (PDT) Received: from [192.168.0.4] ([71.212.132.216]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-6fedcf36a84sm7233271a12.4.2024.06.17.18.28.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Jun 2024 18:28:41 -0700 (PDT) Message-ID: <7fd0eca3-cd15-48c8-ac7f-0967bbada7d2@linaro.org> Date: Mon, 17 Jun 2024 18:28:39 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: linux-user: array overflow in pselect6 emulation To: Andreas Schwab , qemu-devel@nongnu.org References: Content-Language: en-US From: Richard Henderson In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::332; envelope-from=richard.henderson@linaro.org; helo=mail-ot1-x332.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 6/17/24 03:43, Andreas Schwab wrote: > $ cat select.c > #include > #include > #include > #include > #include > #include > > int > main (int argc, char **argv) > { > int nfds = (argc > 1 ? atoi (argv[1]) : 1031); > fd_set *fds = calloc ((nfds + (sizeof (fd_mask) * 8) - 1) > / (sizeof (fd_mask) * 8), sizeof (fd_mask)); > setrlimit (RLIMIT_NOFILE, > &(struct rlimit){ .rlim_cur = nfds, .rlim_max = nfds }); > dup2 (open ("/dev/null", O_RDONLY), nfds - 1); > FD_SET (nfds - 1, fds); > syscall (SYS_pselect6, nfds, fds, 0, 0, 0, 0); > } Ack. We use libc fd_set, which is sized for FD_SETSIZE at 1024. We can either artificially limit RLIMIT_NOFILE (not ideal), or dynamically allocate all fd_set within qemu (which will take some time and effort). r~