From nobody Tue Feb 10 07:23:14 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=linaro.org ARC-Seal: i=1; a=rsa-sha256; t=1768168812; cv=none; d=zohomail.com; s=zohoarc; b=YeCUBCrNFQ7NAArHSBaLfOpJLu/tbADbiEuY8IxeGSDTxcJ/fP3RwNAtZERZabWQuURDLuFgvv3Fg9MYZGsr39JXFRvqldop3GYafgalR7xA71RQ6vbG80d+4mwskQOxbNepkZ3jSWKDwIVL7BQpOLbIeMHI9881Ck2HJLbfUHk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1768168812; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=GVaAl+5IUsLS+7adpLV4oBcC5fg9pMBam+ikbK+jV9M=; b=WAyRgCkLmoHWBfgntjmAiDSDf741R3aaK/A4kDlYQoxP09NWJb/viLgka4NNdLaGu0ushtUk4XD5HCXER19MPvaRSHQFnqJy83CdW88E6kCDJ6dgcCPhWjNcrvXLK7yO6UXtyF+gORFgdkaU6rRtYVrCsizGaSbIdIWhaTtuXXo= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1768168812218825.9434786489464; Sun, 11 Jan 2026 14:00:12 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vf3SY-0005Og-Mh; Sun, 11 Jan 2026 16:58:54 -0500 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 1vf3SX-0005Nw-1a for qemu-devel@nongnu.org; Sun, 11 Jan 2026 16:58:53 -0500 Received: from mail-pl1-x62c.google.com ([2607:f8b0:4864:20::62c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1vf3SV-0003tE-CP for qemu-devel@nongnu.org; Sun, 11 Jan 2026 16:58:52 -0500 Received: by mail-pl1-x62c.google.com with SMTP id d9443c01a7336-2a0d06ffa2aso42935845ad.3 for ; Sun, 11 Jan 2026 13:58:50 -0800 (PST) Received: from stoup.. ([202.86.209.61]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a3e3c3a31dsm155272365ad.9.2026.01.11.13.58.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 11 Jan 2026 13:58:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1768168730; x=1768773530; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=GVaAl+5IUsLS+7adpLV4oBcC5fg9pMBam+ikbK+jV9M=; b=WiIgFczC6yujg2wIm8m+Y0L5f55CxThthtsXdiGN7awQlW0lr2XqDaU1QDhq0hbqQj g7nu+hsgA9hSFSK3dPyZubhod4tl/oSZxUyO1uNckK5w6ulsfyYIEbTb9hy3YOXjf4AA /x7bPHiVnBdFUMBiyN8lIHq9CtLLA7dGO7Toh9JHQ4v5PHfCb1LlDi7pDMUFydIkMiVW wAxqmUamUT7x25zIpENOstI5OXpdRhqvvku07SAxDEXLkOXqn8EUsRvUc+wly8q1hgnU NsW20tQSQrsXFG2mdXM9tNXj5nUQtS/y6vLb4MRz1LmsfjD6EXQwEm8a3PansGE3dnYt nVRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768168730; x=1768773530; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=GVaAl+5IUsLS+7adpLV4oBcC5fg9pMBam+ikbK+jV9M=; b=IhvGathdFMXBqsgWQ3Fyuok9ZCDTyXLbIlW0x2dc4tvy6TNGNG7LMjuzaHWi+B95GL dVp+Ge9DtKgWMUBRE8vSv8qMVq3AffE1BlkxQkMu49ye/cuqLUR1YN/XaQyw4hMmaqw7 dzqAZRh2LxGVu9ZNj/+FqKs4/8mCsHRx+uPHhVnjFC2xMlE2dFgI78sihbw7FTJ9MWok jd454R7+NxhagnL28QuJFpWMm0EL+DyE+xcbcei8hdpa4oZ0syzfBZ73Tn/Rv/Eo80ys 91ECskHsfENvk0YImAyWORtvI5xJSFYpk3cFyIzcudN9HwA89qzUmJSNLB/zyW93BK9V 76Wg== X-Gm-Message-State: AOJu0Yx9rtvCREmf2Iurr/09qEQM3mtXr+vKYCTJvLjLTY0Fwk0efS6p WRfctqot80n9p776saeYd+bTu3YOgnIlXqX9VABumw7D79o4gleqsFbuBv0qgVMzSULC3wENBWJ o7+RPwcY= X-Gm-Gg: AY/fxX7uUDpwCmj2eyln7J8f6ZE5BhzGnn6m9NehzNRJYwfxFiA0fgsoIlNEVwEm1i/ GJWuAUehQi1Ng3tx6Bed7gcLeOgd6Xai7XIXlnSvUcLHCcJWXtqp11jyRITrhyEOEbmpTHN29l8 c/mhcH/BLGncRq5BaxAcLeB5lM2JU6kvMp4FXB6AlvUp54kCY8ikqFU1rbQFYKMGSZ46MzpWOe9 +2tprruHNI8UZxZJq9DsTa03eoUvjWhyngDyN2ObZ5/Fb73DhNy9fuxDTxKDttfMVL1tK9jT9hR 2oj2Nmze/KfsJls6iQquEINyHFd92E0+6pqx6xYiGFej6uZLxBc2nlDufC8evnkYLARJYv0hIrf OoOW/Y2pwaach8DJfTCdOr/QLUhaHxF4JktoxlzWMqfavARbliMmAtZE/lgQldKfPhmm/iyqYtP t/QwETnnmUDwgV14g= X-Google-Smtp-Source: AGHT+IF7hStAS3u2JSfmTtsIL9eDbFwp1Lsc2e+e5g29O9a6FM6oX+flxICbzr1AtHn/2WyOoBZ/uQ== X-Received: by 2002:a17:903:b48:b0:2a0:b02b:210c with SMTP id d9443c01a7336-2a3ee4135a7mr155016435ad.1.1768168729560; Sun, 11 Jan 2026 13:58:49 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: Matthew Lugg Subject: [PULL 09/13] linux-user: fix reserved_va page leak in do_munmap Date: Mon, 12 Jan 2026 08:58:14 +1100 Message-ID: <20260111215819.569209-10-richard.henderson@linaro.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260111215819.569209-1-richard.henderson@linaro.org> References: <20260111215819.569209-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::62c; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62c.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 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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1768168814489158500 Content-Type: text/plain; charset="utf-8" From: Matthew Lugg The old logic had an off-by-one bug. For instance, assuming 4k pages on host and guest, if 'len' is '4097' (indicating to unmap 2 pages), then 'last =3D start + 4096', so 'real_last =3D start + 4095', so ultimately 'real_len =3D 4096'. I do not believe this could cause any observable bugs in guests, because `target_munmap` page-aligns the length it passes in. However, calls to this function in `target_mremap` do not page-align the length, so those calls could "drop" pages, leading to a part of the reserved region becoming unmapped. At worst, a host allocation could get mapped into that hole, then clobbered by a new guest mapping. Signed-off-by: Matthew Lugg Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson Message-ID: <20251117170954.31451-4-mlugg@mlugg.co.uk> --- linux-user/mmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 6163f1a0d1..4bcfaf7894 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -1029,9 +1029,9 @@ static int mmap_reserve_or_unmap(abi_ulong start, abi= _ulong len) void *host_start; int prot; =20 - last =3D start + len - 1; + last =3D ROUND_UP(start + len, TARGET_PAGE_SIZE) - 1; real_start =3D start & -host_page_size; - real_last =3D ROUND_UP(last, host_page_size) - 1; + real_last =3D ROUND_UP(last + 1, host_page_size) - 1; =20 /* * If guest pages remain on the first or last host pages, --=20 2.43.0