From: Eugenio Pérez eperezma@redhat.com
commit 42d84c8490f9f0931786f1623191fcab397c3d64 upstream.
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 eperezma@redhat.com Acked-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [jwang: backport to 4.14] Signed-off-by: Jack Wang jinpu.wang@cloud.ionos.com --- drivers/vhost/net.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 4d11152e60c1..8fe07622ae59 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -1025,11 +1025,7 @@ 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 uaddr_len = sizeof uaddr, r; + int r; struct socket *sock = sockfd_lookup(fd, &r);
if (!sock) @@ -1041,12 +1037,7 @@ static struct socket *get_raw_socket(int fd) goto err; }
- r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, - &uaddr_len, 0); - if (r) - goto err; - - if (uaddr.sa.sll_family != AF_PACKET) { + if (sock->sk->sk_family != AF_PACKET) { r = -EPFNOSUPPORT; goto err; }