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nfsd: check passed socket's net matches NFSd superblock's one 

commit 3064639423c48d6e0eb9ecc27c512a58e38c6c57 upstream.

There could be a case, when NFSd file system is mounted in network, different
to socket's one, like below:

"ip netns exec" creates new network and mount namespace, which duplicates NFSd
mount point, created in init_net context. And thus NFS server stop in nested
network context leads to RPCBIND client destruction in init_net.
Then, on NFSd start in nested network context, rpc.nfsd process creates socket
in nested net and passes it into "write_ports", which leads to RPCBIND sockets
creation in init_net context because of the same reason (NFSd monut point was
created in init_net context). An attempt to register passed socket in nested
net leads to panic, because no RPCBIND client present in nexted network
namespace.

This patch add check that passed socket's net matches NFSd superblock's one.
And returns -EINVAL error to user psace otherwise.

v2: Put socket on exit.

Reported-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stanislav Kinsbursky 2014-02-26 16:50:01 +03:00 committed by Greg Kroah-Hartman
parent b57d9c3fe3
commit 344f3a6bce
3 changed files with 22 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
fs/nfsd/nfsctl.c
View File

@ -699,6 +699,11 @@ static ssize_t __write_ports_addfd(char *buf, struct net *net)
if (err != 0 || fd < 0)
return -EINVAL;
if (svc_alien_sock(net, fd)) {
printk(KERN_ERR "%s: socket net is different to NFSd's one\n", __func__);
return -EINVAL;
}
err = nfsd_create_serv(net);
if (err != 0)
return err;

1
include/linux/sunrpc/svcsock.h
View File

@ -56,6 +56,7 @@ int svc_recv(struct svc_rqst *, long);
int svc_send(struct svc_rqst *);
void svc_drop(struct svc_rqst *);
void svc_sock_update_bufs(struct svc_serv *serv);
bool svc_alien_sock(struct net *net, int fd);
int svc_addsock(struct svc_serv *serv, const int fd,
char *name_return, const size_t len);
void svc_init_xprt_sock(void);

16
net/sunrpc/svcsock.c
View File

@ -1393,6 +1393,22 @@ static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
return svsk;
}
bool svc_alien_sock(struct net *net, int fd)
{
int err;
struct socket *sock = sockfd_lookup(fd, &err);
bool ret = false;
if (!sock)
goto out;
if (sock_net(sock->sk) != net)
ret = true;
sockfd_put(sock);
out:
return ret;
}
EXPORT_SYMBOL_GPL(svc_alien_sock);
/**
* svc_addsock - add a listener socket to an RPC service
* @serv: pointer to RPC service to which to add a new listener