Commit 930b64ca authored by Jeff Layton's avatar Jeff Layton Committed by Chuck Lever
Browse files

nfsd: don't ignore the return code of svc_proc_register() 



Currently, nfsd_proc_stat_init() ignores the return value of
svc_proc_register(). If the procfile creation fails, then the kernel
will WARN when it tries to remove the entry later.

Fix nfsd_proc_stat_init() to return the same type of pointer as
svc_proc_register(), and fix up nfsd_net_init() to check that and fail
the nfsd_net construction if it occurs.

svc_proc_register() can fail if the dentry can't be allocated, or if an
identical dentry already exists. The second case is pretty unlikely in
the nfsd_net construction codepath, so if this happens, return -ENOMEM.

Reported-by: default avatar <syzbot+e34ad04f27991521104c@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/linux-nfs/67a47501.050a0220.19061f.05f9.GAE@google.com/


Cc: stable@vger.kernel.org # v6.9
Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 2ed4f6fe

fs/nfsd/nfsctl.c

+8 −1
Original line number Diff line number Diff line
@@ -2202,8 +2202,14 @@ static __net_init int nfsd_net_init(struct net *net) 
					  NFSD_STATS_COUNTERS_NUM);

	if (retval)

		goto out_repcache_error;



	memset(&nn->nfsd_svcstats, 0, sizeof(nn->nfsd_svcstats));

	nn->nfsd_svcstats.program = &nfsd_programs[0];

	if (!nfsd_proc_stat_init(net)) {

		retval = -ENOMEM;

		goto out_proc_error;

	}



	for (i = 0; i < sizeof(nn->nfsd_versions); i++)

		nn->nfsd_versions[i] = nfsd_support_version(i);

	for (i = 0; i < sizeof(nn->nfsd4_minorversions); i++)
@@ -2213,13 +2219,14 @@ static __net_init int nfsd_net_init(struct net *net) 
	nfsd4_init_leases_net(nn);

	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));

	seqlock_init(&nn->writeverf_lock);

	nfsd_proc_stat_init(net);

#if IS_ENABLED(CONFIG_NFS_LOCALIO)

	spin_lock_init(&nn->local_clients_lock);

	INIT_LIST_HEAD(&nn->local_clients);

#endif

	return 0;



out_proc_error:

	percpu_counter_destroy_many(nn->counter, NFSD_STATS_COUNTERS_NUM);

out_repcache_error:

	nfsd_idmap_shutdown(net);

out_idmap_error:

fs/nfsd/stats.c

+2 −2
Original line number Diff line number Diff line
@@ -73,11 +73,11 @@ static int nfsd_show(struct seq_file *seq, void *v) 


DEFINE_PROC_SHOW_ATTRIBUTE(nfsd);



void nfsd_proc_stat_init(struct net *net)

struct proc_dir_entry *nfsd_proc_stat_init(struct net *net)

{

	struct nfsd_net *nn = net_generic(net, nfsd_net_id);



	svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);

	return svc_proc_register(net, &nn->nfsd_svcstats, &nfsd_proc_ops);

}



void nfsd_proc_stat_shutdown(struct net *net)

fs/nfsd/stats.h

+1 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ 
#include <uapi/linux/nfsd/stats.h>

#include <linux/percpu_counter.h>



void nfsd_proc_stat_init(struct net *net);

struct proc_dir_entry *nfsd_proc_stat_init(struct net *net);

void nfsd_proc_stat_shutdown(struct net *net);



static inline void nfsd_stats_rc_hits_inc(struct nfsd_net *nn)