[PATCH v6 07/18] nfsd/localio: manage netns reference in nfsd_open_local_fh

Mike Snitzer
2024-06-19T20:40:43Z

Use maybe_get_net() and put_net() in nfsd_open_local_fh().
Also refactor nfsd_open_local_fh() slightly.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
fs/nfsd/localio.c | 45 ++++++++++++++++++++++++++-------------------
1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c
index e9aa0997f898..f6df66b1d523 100644
--- a/fs/nfsd/localio.c
+++ b/fs/nfsd/localio.c
@@ -99,18 +99,11 @@ nfsd_local_fakerqst_destroy(struct svc_rqst *rqstp)

static struct svc_rqst *
nfsd_local_fakerqst_create(struct net *net, struct rpc_clnt *rpc_clnt,
- const struct cred *cred)
+ const struct cred *cred, struct svc_serv *serv)
{
struct svc_rqst *rqstp;
- struct nfsd_net *nn = net_generic(net, nfsd_net_id);
int status;

- /* FIXME: not running in nfsd context, must get reference on nfsd_serv */
- if (unlikely(!READ_ONCE(nn->nfsd_serv))) {
- dprintk("%s: localio denied. Server not running\n", __func__);
- return ERR_PTR(-ENXIO);
- }
-
rqstp = kzalloc(sizeof(*rqstp), GFP_KERNEL);
if (!rqstp)
return ERR_PTR(-ENOMEM);
@@ -120,13 +113,13 @@ nfsd_local_fakerqst_create(struct net *net, struct rpc_clnt *rpc_clnt,
status = -ENOMEM;
goto out_err;
}
-
rqstp->rq_xprt->xpt_net = net;
+
__set_bit(RQ_SECURE, &rqstp->rq_flags);
rqstp->rq_proc = 1;
rqstp->rq_vers = 3;
rqstp->rq_prot = IPPROTO_TCP;
- rqstp->rq_server = nn->nfsd_serv;
+ rqstp->rq_server = serv;

/* Note: we're connecting to ourself, so source addr == peer addr */
rqstp->rq_addrlen = rpc_peeraddr(rpc_clnt,
@@ -188,28 +181,44 @@ int nfsd_open_local_fh(struct net *net,
const fmode_t fmode,
struct file **pfilp)
{
+ struct nfsd_net *nn;
const struct cred *save_cred;
struct svc_rqst *rqstp;
struct svc_fh fh;
struct nfsd_file *nf;
int status = 0;
int mayflags = NFSD_MAY_LOCALIO;
+ struct svc_serv *serv;
__be32 beres;

+ if (nfs_fh->size > NFS4_FHSIZE)
+ return -EINVAL;
+
+ /* Not running in nfsd context, must safely get reference on nfsd_serv */
+ net = maybe_get_net(net);
+ if (!net) {
+ dprintk("%s: localio denied. Server netns not available\n", __func__);
+ return -ENXIO;
+ }
+ nn = net_generic(net, nfsd_net_id);
+
+ serv = READ_ONCE(nn->nfsd_serv);
+ if (unlikely(!serv)) {
+ dprintk("%s: localio denied. Server not running\n", __func__);
+ status = -ENXIO;
+ goto out_net;
+ }
+
/* Save creds before calling into nfsd */
save_cred = get_current_cred();

- rqstp = nfsd_local_fakerqst_create(net, rpc_clnt, cred);
+ rqstp = nfsd_local_fakerqst_create(net, rpc_clnt, cred, serv);
if (IS_ERR(rqstp)) {
status = PTR_ERR(rqstp);
goto out_revertcred;
}

/* nfs_fh -> svc_fh */
- if (nfs_fh->size > NFS4_FHSIZE) {
- status = -EINVAL;
- goto out;
- }
fh_init(&fh, NFS4_FHSIZE);
fh.fh_handle.fh_size = nfs_fh->size;
memcpy(fh.fh_handle.fh_raw, nfs_fh->data, nfs_fh->size);
@@ -225,17 +234,15 @@ int nfsd_open_local_fh(struct net *net,
dprintk("%s: fh_verify failed %d\n", __func__, status);
goto out_fh_put;
}
-
*pfilp = get_file(nf->nf_file);
-
nfsd_file_put(nf);
out_fh_put:
fh_put(&fh);
-
-out:
nfsd_local_fakerqst_destroy(rqstp);
out_revertcred:
revert_creds(save_cred);
+out_net:
+ put_net(net);
return status;
}
EXPORT_SYMBOL_GPL(nfsd_open_local_fh);
--
2.44.0