From patchwork Sun Aug 6 03:36:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 1817425 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=Z6EF2Sf0; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RJQDj5CtMz1yYl for ; Sun, 6 Aug 2023 13:39:33 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qSUa6-0003e0-4P; Sat, 05 Aug 2023 23:37:26 -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 1qSUa4-0003ct-Ne for qemu-devel@nongnu.org; Sat, 05 Aug 2023 23:37:24 -0400 Received: from mail-pg1-x52b.google.com ([2607:f8b0:4864:20::52b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qSUa2-0007Wz-PE for qemu-devel@nongnu.org; Sat, 05 Aug 2023 23:37:24 -0400 Received: by mail-pg1-x52b.google.com with SMTP id 41be03b00d2f7-564ef63a010so150994a12.0 for ; Sat, 05 Aug 2023 20:37:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1691293041; x=1691897841; 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=Y+al/bCM9dfQjUvbH6ERA5E1FapPNk6WKGGZIMvtMEA=; b=Z6EF2Sf0dU/8E+SPlQPBdWKP+TPG6VnwppJXQ3uUy8Bc2zcbW6CnsRa6482Z74/ZMp +UxmqedwJQbsNmWCeNoX9OQIjf4owyYQihCnTBMKsjrCae9bXRgOCjC+xc+50nL63sm+ 3kf0okqRV2C6Z7efjbLyYBTObkrXUeDkuVbjWbifVhtQDKo+Jpt3xHvv8R4eXhGfuEwp ho06D79uKXjgNL5eEcMFKG0MrusQriTzx8xzjzklfnWCzp/bJwLaG57tS/Ndfy8YkmyQ O7PVPzBUseqqyL8MWeoiJpVA2gwbAyXBGKiMGRv6e/QJdoKFIjo3BaGfih6qDl/x5hTZ N9tQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691293041; x=1691897841; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Y+al/bCM9dfQjUvbH6ERA5E1FapPNk6WKGGZIMvtMEA=; b=e7NAPZ94qRzMutIy5md1HTjHjMTOJi/usT/8fTeswQDFfOsUztDaCrEbTOri9MxP8Q ypOsl6EVkwm8lWeMZBLOCWbA1JKOycbXCvogQ8qgq57D7fJ5T7LMR8p8TkpNq+WKgkqv QrFrUP0JDcQ8xJfiPcTtgB06yepYoGGmH7bSUI+e/EZnVT8yMg4AMDWQJ60040Y+bj3T tzy7U/CM6+RIEApfa5afycGQWyva2LuXSiSaUPkPrD6ZUUSpZCN3N6LXqpDe0ohJK8Hp ZK+SyDRd48ob/wm35/J4ZTwy3oVuyHrNOjUHqBkeY3U5DS3f3ZcfZqq5vkDTmSBa3lnF zCqA== X-Gm-Message-State: AOJu0Yz2TFi1A6iJj2d2uZquFJ+30IMsRwLNMciN/amYoEI3Z96qcFG3 goL1JT7o5za4UDA8gEHOHKMFnjK7eFuV4EMFgKU= X-Google-Smtp-Source: AGHT+IGgSqD1df9CIqMQdf3uai89JpKwhXap63RN40/JNlECHJXUvUm7lzPvm4QOIGn+Jm1HNlC3IA== X-Received: by 2002:a17:90a:5512:b0:260:a8da:536c with SMTP id b18-20020a17090a551200b00260a8da536cmr4672093pji.23.1691293041161; Sat, 05 Aug 2023 20:37:21 -0700 (PDT) Received: from stoup.. ([2602:47:d490:6901:9454:a46f:1c22:a7c6]) by smtp.gmail.com with ESMTPSA id a5-20020a17090a740500b00262e604724dsm6306451pjg.50.2023.08.05.20.37.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Aug 2023 20:37:20 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: Akihiko Odaki Subject: [PULL 06/24] linux-user: Fix MAP_FIXED_NOREPLACE on old kernels Date: Sat, 5 Aug 2023 20:36:57 -0700 Message-Id: <20230806033715.244648-7-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230806033715.244648-1-richard.henderson@linaro.org> References: <20230806033715.244648-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::52b; envelope-from=richard.henderson@linaro.org; helo=mail-pg1-x52b.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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Akihiko Odaki The man page states: > Note that older kernels which do not recognize the MAP_FIXED_NOREPLACE > flag will typically (upon detecting a collision with a preexisting > mapping) fall back to a “non-MAP_FIXED” type of behavior: they will > return an address that is different from the requested address. > Therefore, backward-compatible software should check the returned > address against the requested address. https://man7.org/linux/man-pages/man2/mmap.2.html Signed-off-by: Akihiko Odaki Message-Id: <20230802071754.14876-3-akihiko.odaki@daynix.com> Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- linux-user/mmap.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index a11c630a7b..90b3ef2140 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -263,7 +263,11 @@ static bool mmap_frag(abi_ulong real_start, abi_ulong start, abi_ulong last, void *p = mmap(host_start, qemu_host_page_size, target_to_host_prot(prot), flags | MAP_ANONYMOUS, -1, 0); - if (p == MAP_FAILED) { + if (p != host_start) { + if (p != MAP_FAILED) { + munmap(p, qemu_host_page_size); + errno = EEXIST; + } return false; } prot_old = prot; @@ -687,17 +691,25 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, /* map the middle (easier) */ if (real_start < real_last) { - void *p; + void *p, *want_p; off_t offset1; + size_t len1; if (flags & MAP_ANONYMOUS) { offset1 = 0; } else { offset1 = offset + real_start - start; } - p = mmap(g2h_untagged(real_start), real_last - real_start + 1, - target_to_host_prot(target_prot), flags, fd, offset1); - if (p == MAP_FAILED) { + len1 = real_last - real_start + 1; + want_p = g2h_untagged(real_start); + + p = mmap(want_p, len1, target_to_host_prot(target_prot), + flags, fd, offset1); + if (p != want_p) { + if (p != MAP_FAILED) { + munmap(p, len1); + errno = EEXIST; + } goto fail; } passthrough_start = real_start;