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[109.67.14.209]) by smtp.gmail.com with ESMTPSA id m23sm1336239qtp.6.2020.02.21.03.11.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Feb 2020 03:11:32 -0800 (PST) Date: Fri, 21 Feb 2020 06:11:27 -0500 From: "Michael S. Tsirkin" To: Eugenio =?iso-8859-1?Q?P=E9rez?= Cc: jasowang@redhat.com, kvm@vger.kernel.org, netdev@vger.kernel.org, stable@vger.kernel.org, jreuter@yaina.de, ralf@linux-mips.org Subject: Re: [PATCH] vhost: Check docket sk_family instead of call getname Message-ID: <20200221060916-mutt-send-email-mst@kernel.org> References: <20200221110656.11811-1-eperezma@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200221110656.11811-1-eperezma@redhat.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Feb 21, 2020 at 12:06:56PM +0100, Eugenio Pérez wrote: > 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 Thanks for debugging this! 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; > } > -- > 2.18.1