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=TDlF9ZP9RjsZnfeq72MVW6awvm5HBL1hx76i5oh0FH/+ZCWzPeFjm0Qqu36YWCjinFLZ zCQSQLB2NHvGWRvetnaS4wjF03wOG/MBkecN/dKtTuaYB1OkcPcG9I4YiG0AO83zQPr1Z +h15ljDHLYjTo4eTmk2PRkW/fGfXQonq+FZN4XD0RbGQJPuxOJnQDbQ69jQHCEI7veHkG 9yfhw3YxXYbcE2MKPtIHM0RRd26CuYactg/CWQFodCXJOuEiZ5M4esCQn6w2zQEqYW3kH 7j2HMiG5MzZm6FIdXX3IM5QtR/JLCneqTKEph8QKbuWPS5IBUj001kwZwsH68ZO7YwQ== 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=jaW+HgoYxuLQQBZmfWzqglUsinSUxTNVEVzR7DTqZgN4Is9dS0aF1i/KYu38w454mBiM /OAYuu031YO94qlYarxq2x67crrITqDhJyhbgNwGIUt1EBw+UvJGACBrHR4U4PtgJorWg TpJAxi/CJWjw6nI+GUzmP1sB7gngU++hu+FVj/X1UvPzXjFE4+aWb908N3JdWmxjmHQk2 kWKzlQfVH0cFq+uo7U71isF/gVqXWwPheT9AqG256OhzvTMeemVpXgD9T1LhRyn3HQicX yKhbkPt/YKDWq5b+6WEYWRWn0yjQylI67A7++zP8FqUWpDRsV/OtisBS76X2jjhEQPw== 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 7461B606A31C for ; Wed, 28 Oct 2026 21:06:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 7461B606A31C 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: v9fs@lists.linux.dev 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