From: Eugenio Pérez <epere...@redhat.com>

[ Upstream commit 42d84c8490f9f0931786f1623191fcab397c3d64 ]

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+f2a62d07a5198c819...@syzkaller.appspotmail.com
Signed-off-by: Eugenio Pérez <epere...@redhat.com>
Acked-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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 e158159671fa2..18e205eeb9af7 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;
        }
-- 
2.20.1

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