From patchwork Fri Feb 21 11:06:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Eugenio Perez Martin X-Patchwork-Id: 11396241 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 91E301395 for ; Fri, 21 Feb 2020 11:07:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70FF224672 for ; Fri, 21 Feb 2020 11:07:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dMftVPSP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727795AbgBULHO (ORCPT ); Fri, 21 Feb 2020 06:07:14 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:29488 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727498AbgBULHO (ORCPT ); Fri, 21 Feb 2020 06:07:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582283233; 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; bh=4kIIIjMqTYsRdUJ8TW9Ts/lWmHycKGBkTxfc9vga4Ow=; b=dMftVPSPuDapVtL2qTsYd7mEPsokzX70/Jcg9RRNwveyjEltbSk2Tieut+FntVJjKIz4rV cWZi3YjKT7cYRe3J0Bf4tF95d3E1UF7dhmdTBv8BeOiRc/vZiBw3Fc3K5WAczQCDSebnOm 4Y8AAg9NFht1n0HUrWK2BuXNjRsRJAE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-353-B40GITilO5aQ4FQuPBp4bA-1; Fri, 21 Feb 2020 06:07:06 -0500 X-MC-Unique: B40GITilO5aQ4FQuPBp4bA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1C4681882CCC; Fri, 21 Feb 2020 11:07:04 +0000 (UTC) Received: from eperezma.remote.csb (ovpn-117-58.ams2.redhat.com [10.36.117.58]) by smtp.corp.redhat.com (Postfix) with ESMTP id C7B1319C6A; Fri, 21 Feb 2020 11:06:59 +0000 (UTC) From: =?utf-8?q?Eugenio_P=C3=A9rez?= To: mst@redhat.com, jasowang@redhat.com, kvm@vger.kernel.org, netdev@vger.kernel.org Cc: stable@vger.kernel.org, jreuter@yaina.de, ralf@linux-mips.org, eperezma@redhat.com Subject: [PATCH] vhost: Check docket sk_family instead of call getname Date: Fri, 21 Feb 2020 12:06:56 +0100 Message-Id: <20200221110656.11811-1-eperezma@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Doing so, we save one call to get data we already have in the struct. Also, since there is no guarantee that getname use sockaddr_ll parameter beyond its size, we add a little bit of security here. It should do not do beyond MAX_ADDR_LEN, but syzbot found that ax25_getname writes more (72 bytes, the size of full_sockaddr_ax25, versus 20 + 32 bytes of sockaddr_ll + MAX_ADDR_LEN in syzbot repro). Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server") Reported-by: syzbot+f2a62d07a5198c819c7b@syzkaller.appspotmail.com Signed-off-by: Eugenio Pérez Acked-by: Michael S. Tsirkin --- drivers/vhost/net.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index e158159671fa..18e205eeb9af 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1414,10 +1414,6 @@ static int vhost_net_release(struct inode *inode, struct file *f) static struct socket *get_raw_socket(int fd) { - struct { - struct sockaddr_ll sa; - char buf[MAX_ADDR_LEN]; - } uaddr; int r; struct socket *sock = sockfd_lookup(fd, &r); @@ -1430,11 +1426,7 @@ static struct socket *get_raw_socket(int fd) goto err; } - r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 0); - if (r < 0) - goto err; - - if (uaddr.sa.sll_family != AF_PACKET) { + if (sock->sk->sk_family != AF_PACKET) { r = -EPFNOSUPPORT; goto err; }