Commit 42d84c84 authored Feb 21, 2020 by Eugenio Pérez Committed by David S. Miller Feb 22, 2020

vhost: Check docket sk_family instead of call getname



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: 3a4d5c94 ("vhost_net: a kernel-level virtio server")
Reported-by:  <syzbot+f2a62d07a5198c819c7b@syzkaller.appspotmail.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 0c0ddd6a

drivers/vhost/net.c

+1 −9

Original line number	Diff line number	Diff line
		@@ -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;
		}

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