From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=62.210.214.84 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793221582; b=inj9Jx5RSEDSDULbcLzmQA0Qzgtn16fjFvc+E0r3a+ya6ZUgtWpD31xVjaf23SOz1J7j oweFQ8zxE9ch1+9I2F/qpim+onzgf1+BSGHSGApphEgGBHTcL0DcqOJ1LWx/lLyXRXqq+ 2qCNVy7CK8NAur2L5xb5fjNuJ9Y2IH7nPE/FobaHaelTvnAeJpNHaeIg0z777Sg04ICtX AUESTtmb9NrUWFymMJJnW9mu1CwbW7n8Is2QVDFMZmuwE0x75bgBFszVppK2OAPDHn7ev Y2zq0q/rM14okO1MTi8uOUaQzVrjiQnVJjbdceHHZVzUOsUuHJviFhFQUmhDkdXRBXQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793221582; h=DMARC-Filter:Received:DKIM-Signature:Received:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:Content-Transfer-Encoding:In-Reply-To; bh=1U4kkjWGgsDvjjFH6rA1YeOtK+lamjZuaWRgy38Z+iY=; b=xsKnDdOF6DY8bPNPK0U/YoRG7Udhh/v5Mx/BGRF7rpNQ+TuAzokKxMbV3VvOKX8WwLer NvqFu70AooF89NeQlzcUhEeEe+xV/Yg+XC+M0zuy1YQUECuXfPmc7TjLDQzA0aA5yxWsL Z1duQgfHjZeJQ0w6PKLoS5ZRoyPOFeHJ5ReLg79w32PRD9W6dgzHXaeknN4+IEwn5N3aP T3iVNBKanIwnK42x5jo9hnpwwfAGdXH3k5SdE0pHTOgU5s97kgouSJZIOcXvTKd9jHh1A 7FlS61ELvkhSOSmemtEXNSTAItLIy3OH461m2YK5BoOk2gQiGlHMmdLbh2bezMBf5AQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass header.d=codewreck.org header.i=@codewreck.org header.a=rsa-sha256 header.s=2 header.b=zfhRCywQ; arc=none smtp.remote-ip=62.210.214.84 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 746F2606A31D; Wed, 28 Oct 2026 21:06:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 746F2606A31D Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=codewreck.org header.i=@codewreck.org header.a=rsa-sha256 header.s=2 header.b=zfhRCywQ Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id 5555814C2D6; Wed, 28 Oct 2026 22:06:15 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1793221579; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1U4kkjWGgsDvjjFH6rA1YeOtK+lamjZuaWRgy38Z+iY=; b=zfhRCywQm397mApgZmVGmGOur7Ab9RM9b73cQf81jpGS2JpQ0H7LFelfeZ4xziGR9tqxHP eDS26RIkkmvE5T86bUJaddC82b3ABEnmrM1VyXQ/stLD7xs/vOBRRa/dm9zBWVUC2tr8my 69fePCmEK4ZpsJgOSjtVQy1vFbroO359N4t166tnP2k9lb+Z0gijXGRWaNHCqGcH2FVznb viEeBDt5KuHOjXWo+po/nipEwiduyWk8qXen61oyTtfudYvFmKw09Enfx6fGT11LpMSKRk jv9h3nVBT5IqkNsJsGiM4RZS5TtLF03h2KjdPG3RKk14e2JPPFFhaC4fIMQG9w== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id 370ff9f9; Wed, 28 Oct 2026 21:06:13 +0000 (UTC) Date: Thu, 29 Oct 2026 06:05:58 +0900 From: Dominique Martinet To: Juergen Gross Cc: Yizhou Zhao , v9fs@lists.linux.dev, Eric Van Hensbergen , Latchesar Ionkov , Christian Schoenebeck , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Yuxiang Yang , Ao Wang , Xuewei Feng , Qi Li , Ke Xu , Stefano Stabellini Subject: Re: [PATCH] 9p/xen: drain response work after unbinding IRQ Message-ID: References: <20260609155202.1706-1-zhaoyz24@mails.tsinghua.edu.cn> <4d97500e-a489-4e64-aa11-29c3430909f3@suse.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4d97500e-a489-4e64-aa11-29c3430909f3@suse.com> Juergen Gross wrote on Thu, Oct 08, 2026 at 12:42:21PM +0200: > > This one makes sense to me and I've picked it up, but I think > > "9p/xen: fix use-after-free in p9_xen_request"[1] adding a refcount to > > the front_priv is too much complexity vs. my understanding of the > > current threat model -- I can pick it up if someome who understands xen > > better than me has a proper look. > > > > Stefano or Jürgen if you care / have time? > > > > [1] https://lore.kernel.org/r/20260529103416.81378-1-zhaoyz24@mails.tsinghua.edu.cn > > I think [1] should be taken. > > We try to harden frontends against potentially malicious backends running > in a driver domain. Such a backend could cause the device to be removed on > the frontend side, so the attack vector is present. > > The only reason this doesn't qualify as a Xen security issue is that the > 9pfs frontend hasn't been yet declared to be security supported regarding > attacks by the backend. Hopefully we will get there. As said above I'm happy to take it under the condition that someone who can validate the patch has a proper look; I don't have much time for 9p right now and my setup doesn't include any test for xen so I'd rather be cautious Thanks, -- Dominique Martinet | Asmadeus