| Message ID | 20200221110656.11811-1-eperezma@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost: Check docket sk_family instead of call getname | expand |
On Fri, Feb 21, 2020 at 12:06:56PM +0100, Eugenio Pérez wrote: > 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> Thanks for debugging this! Acked-by: Michael S. Tsirkin <mst@redhat.com> > --- > 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 e158159671fa..18e205eeb9af 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; > } > -- > 2.18.1
From: Eugenio Pérez <eperezma@redhat.com> Date: Fri, 21 Feb 2020 12:06:56 +0100 > 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> Applied and queued up for -stable, thanks.
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index e158159671fa..18e205eeb9af 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; }
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> --- drivers/vhost/net.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-)