From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B2C59411FBB for ; Sun, 18 Oct 2026 22:13:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792361617; cv=none; b=JQofeHQhJrXV6G2QdLxDNrRaRC5heCOepcx26eyCjWws9NjkxHvCMSRjgcASfa7pR20e3+MWx1VB9/Gm37i5T5nwmYX6zVhwmTUtynBecZfUR05qUIEUPhQl4hxeJLK6VxBH20z6khxUrFkGBtoqY/dhTCtFjdwM520BDDI/PCE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792361617; c=relaxed/simple; bh=JBnh6g8/khXfo/xjv3nRYstO4SCCAW5vzbTZ2OoUIp4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tOl+zySvrifB88lcuVfJVXfJ89UKFTZ48zsWk6ROll1KM1aApyS+6uVIUN4xhIvHXp3GoIQRPNtXuLQPNZz4ful78XBLLp1SbdbpzcQ3gxcrJ2FwRe9KqDDJV5L+RMlG2U01I6G9TMTHJAAdxWx83Ke6nVSjgt2vZlnMowr8rJ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=gsLpHUv6; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=UK7LpVC5; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gsLpHUv6"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="UK7LpVC5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1792361614; 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=D2nWTmEzSlPTSS6/bv2DXBvJ1IMAaQG+TiNBhHr6z6k=; b=gsLpHUv6XRn7KQb2DbuEhMEV3nhOb/rQk+DoA4pjYS0Iw5sVuo16T4nEk0HZIBNtIUaYbj E2J47yTC4/R+IlflrVA9rrGeO86tUOsyF8trKct0jn7dd8sVH2V+sJv8aMmH5uF+Zo5BFz Qj4jLTJyXwF53IqbiQwPVLcFXgRg6Co= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-149-4YQfalDvOlKd2-hlHQBRzg-1; Sun, 18 Oct 2026 22:13:33 +0000 X-MC-Unique: 4YQfalDvOlKd2-hlHQBRzg-1 X-Mimecast-MFC-AGG-ID: 4YQfalDvOlKd2-hlHQBRzg_1792361612 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-48e1291432aso341392f8f.2 for ; Sun, 18 Oct 2026 15:13:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1792361612; x=1792966412; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :content-type:mime-version:references:message-id:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to:content-type; bh=D2nWTmEzSlPTSS6/bv2DXBvJ1IMAaQG+TiNBhHr6z6k=; b=UK7LpVC5ynnkkWWJnerT/vvL6GRVLxZzYw9dSFiA6TOTwmacWDvb0JnUgfqZmrU8Z8 Cqva6B7MOWfLsFoBx3RczGjP/5sFmiMGMFft6qiJfRVi7n96+3FQG1fuKZbSlUF1/6jA ye8xT6ayeZhCESJZKPq5LdloJ1Vtfgq+VAFSA0xzdNIS7bj/S1kGfxqkdf9weUrwo+ue jFELfkq/ZEz7Rgmnvhxk+hbZM61kD+qbxIwGVTHPUuJ0IdMNZ/E0DHAsrZN+54OrCYeM EYguIh+BrZ6pLnjzr8zB4URPOVw86L0c8Tc43OZmU3a18hHx9dXmOpn1VI1GOP+Z4UHF RKPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792361612; x=1792966412; h=in-reply-to:content-transfer-encoding:content-disposition :content-type:mime-version:references:message-id:subject:cc:to:from :date:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=D2nWTmEzSlPTSS6/bv2DXBvJ1IMAaQG+TiNBhHr6z6k=; b=vAZDiHx207EuotWfSqFj9Nn1pQOtZ8G8qxPo8ZmYoqo9T4FLouI++kYjket5Bl5vVe i5ieytUGUwb3dirh0XiraJkChfZgdD532FTrgC6ieA6j3ML988bxkcY2ZDZyTHiJh791 4/L+c2ogz5/z/4oZu7vhAR8TkRFt6XF2FEX1lsc/JMxoR39c3dEuGfGtGydtcuuafUuA NWOJD39RfIjqxd3OXqucqDBu47RKKuHBk+HgygfGAexFMg7osynafWZ9gSognmthCl5b MF258/IQFDDi5CkJYdJ9j0tDoxKt9LIHFZ/iFLzvT1U0jFLnznPKnCa9KdEDXC3vVEEW 8PHQ== X-Forwarded-Encrypted: i=1; AKwUvBxLQ03fKas7z8VLN8G90BS5UTp/D3aKAhotlD2vfmYWX0zBOL7WQnaCKkEycRhb6v9WWR964X8UJXDnr7Y=@vger.kernel.org X-Gm-Message-State: AFq9FYJyO16lhuAVulgZzBzauJRuyX03mzIoKHu9rvu4koMHCLKQ2gfB FygnXcopl9IBmVqgvrVRdd1Q7CtbDG1BX1Xfjyn1iDh9GEZC9SLs1Nsa7kmRXYwSUI8UqaYm26r ovmwcjtsEuuUc34LUZFCQUHqZfXCl094wd5/47dCjMbrbR2QlvZeYLqn85YtwsNWYMw== X-Gm-Gg: AYBFou1E9LH0mmUeaf5CZyjvb1IDDx0Ao+YQD9u9DIqAtxxDZJ343OQ+2jurVZVubrV QOPopUNwyu+VNEAb44DtnBUadqqi0d4irn79jLupD+ueBbKo8RfGxo/8yTKCHarMdinHu75Xs/5 cJYIp0zAIC5Qg9yNEajDTlGHLglN30BcY+Ht0tR5KiR9q3vz4r66Qw/uNyoZGBtwFea3JdGOIlf Tjrh/WemIM39IZi1ELYaWXPRbVDUih5wflu6LDwGSfG6pIUD1vJ+i8v/K5cbomPGz1Wdelia0ea ao3Cc5tvXZuvJZCMVizNPawkueNORvEVAgkocXwP6mf3jB5+S5iQ2yxJXyFW7vCHQ81wOA== X-Received: by 2002:a05:600c:548d:b0:4a1:e250:b191 with SMTP id 5b1f17b1804b1-4a1e250b1c7mr52451185e9.17.1792361611687; Sun, 18 Oct 2026 15:13:31 -0700 (PDT) X-Received: by 2002:a05:600c:548d:b0:4a1:e250:b191 with SMTP id 5b1f17b1804b1-4a1e250b1c7mr52450995e9.17.1792361611317; Sun, 18 Oct 2026 15:13:31 -0700 (PDT) Received: from redhat.com ([2a0d:6fc0:3fd7:5300:3d6b:52a4:a23f:9d0b]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48dfd471a72sm20914904f8f.4.2026.10.18.15.13.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 18 Oct 2026 15:13:29 -0700 (PDT) Date: Sun, 18 Oct 2026 18:13:26 -0400 From: "Michael S. Tsirkin" To: Linus Torvalds Cc: David Laight , Haoran Wang , jasowangio@gmail.com, KVM list , virtualization@lists.linux.dev, Netdev , Eugenio =?iso-8859-1?Q?P=E9rez?= , Linux Kernel Mailing List , Security Officers Subject: Re: [BUG] vhost/vringh: __get_user without access_ok leaks kernel memory via vDPA passthrough Message-ID: <20261018181202-mutt-send-email-mst@kernel.org> References: <6ad07f8a.a0c71a5e.2d2efd.977a@mx.google.com> <20261018152358-mutt-send-email-mst@kernel.org> <20261018204838.4080b238@pumpkin> <20261018175347-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Sun, Oct 18, 2026 at 12:06:36PM -1000, Linus Torvalds wrote: > > > > + > > > > +           if (!access_ok(uaddr, sizeof(*p))) > > > > +                   return -EFAULT; > > > > +           ret = __get_user(tmp, uaddr); > > > > > > Can't that be a normal get_user() call? > > > > > > David > > > > Ugh, actually no. This is called under local_bh_disable. > > > > get_user would splat on might_sleep. > I[ sorry for html - driving around ] > > That's a separate bug, and you really shouldn't use __get_user to work around > it just because it doesn't check.  > > You should use pagefault_disable() around the access. And if there is still a > sleep_on() complaint, that should be fixed.  > >         Linus Thanks Linus, will look into this. -- MST