Sasha Levin
2020-Mar-05 17:13 UTC
[PATCH AUTOSEL 5.4 26/58] vhost: Check docket sk_family instead of call getname
From: Eugenio P?rez <eperezma at 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+f2a62d07a5198c819c7b at syzkaller.appspotmail.com Signed-off-by: Eugenio P?rez <eperezma at redhat.com> Acked-by: Michael S. Tsirkin <mst at redhat.com> Signed-off-by: David S. Miller <davem at davemloft.net> Signed-off-by: Sasha Levin <sashal at 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 1a2dd53caadea..b53b6528d6ce2 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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