Commit 42d84c84 authored by Eugenio Pérez's avatar Eugenio Pérez Committed by David S. Miller

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: default avatarEugenio Pérez <eperezma@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0c0ddd6a
...@@ -1414,10 +1414,6 @@ static int vhost_net_release(struct inode *inode, struct file *f) ...@@ -1414,10 +1414,6 @@ static int vhost_net_release(struct inode *inode, struct file *f)
static struct socket *get_raw_socket(int fd) static struct socket *get_raw_socket(int fd)
{ {
struct {
struct sockaddr_ll sa;
char buf[MAX_ADDR_LEN];
} uaddr;
int r; int r;
struct socket *sock = sockfd_lookup(fd, &r); struct socket *sock = sockfd_lookup(fd, &r);
...@@ -1430,11 +1426,7 @@ static struct socket *get_raw_socket(int fd) ...@@ -1430,11 +1426,7 @@ static struct socket *get_raw_socket(int fd)
goto err; goto err;
} }
r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 0); if (sock->sk->sk_family != AF_PACKET) {
if (r < 0)
goto err;
if (uaddr.sa.sll_family != AF_PACKET) {
r = -EPFNOSUPPORT; r = -EPFNOSUPPORT;
goto err; goto err;
} }
......
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