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 lists1p.gnu.org (lists1p.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 185F7C88E7B for ; Tue, 15 Sep 2026 11:14:48 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x6R7X-0005N1-8c; Tue, 15 Sep 2026 07:14:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x6R7V-0005Mf-HF for qemu-devel@nongnu.org; Tue, 15 Sep 2026 07:14:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x6R7T-0007cG-So for qemu-devel@nongnu.org; Tue, 15 Sep 2026 07:14:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1789470874; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Y2FHDy233jSQ0MflIxmvlmfT4HcWxCHiBCAFzBPjrBc=; b=bs4yLffsbKfJeCmr9VgkXq9S8208z+Ft7Pg+V2oXJiNVUdYVfGjKGn5IcLAFxuJpaqw2Ib ZzF0SLH95UKwYVXH5jJ8/XNgGl3x2wwOvMCJoXdr/1a6o9Zw2RK0H9wfZpDe/DCFRqR3x0 Jj2H/5ZUOWcZEKPJ00+xO0zZLoeYPYU= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-278-W5NgKwZhM_6GXsCkSVB6YQ-1; Tue, 15 Sep 2026 07:14:31 -0400 X-MC-Unique: W5NgKwZhM_6GXsCkSVB6YQ-1 X-Mimecast-MFC-AGG-ID: W5NgKwZhM_6GXsCkSVB6YQ_1789470870 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C6EA21955BCE; Tue, 15 Sep 2026 11:14:29 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.5]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3786C1956045; Tue, 15 Sep 2026 11:14:29 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id B7CBC21E6A04; Tue, 15 Sep 2026 13:14:26 +0200 (CEST) From: Markus Armbruster To: Bin Guo Cc: "Dr . David Alan Gilbert" , Fabiano Rosas , Laurent Vivier , Paolo Bonzini , qemu-devel@nongnu.org Subject: Re: [PATCH] monitor/hmp: detect signed integer overflow in expression evaluator In-Reply-To: <20260915075312.50612-1-guobin@linux.alibaba.com> (Bin Guo's message of "Tue, 15 Sep 2026 15:53:12 +0800") References: <20260915075312.50612-1-guobin@linux.alibaba.com> Date: Tue, 15 Sep 2026 13:14:26 +0200 Message-ID: <87zexipy0d.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Bin Guo writes: > The HMP expression evaluator performed *, +, - and unary - on int64_t > values without checking for overflow. A malformed expression such as > "0x7fffffffffffffff + 1" would silently wrap around to INT64_MIN and > could then be passed as a physical address to the "xp" command. Isn't that a feature? It wraps to (int64_t)0x8000000000000000, is put in the argument QDict, passed to hmp_physical_memory_dump(), which implicitly converts to uint64_t, then passes to memory_dump(). Such cavalier signedness conversions are endemic in old C code like this. The same conversions happen when you write the expression as "0x8000000000000000" instead. [...]