Commit 9affa435 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: fix NULL dereference in nfsd/clients display code 



We hold the cl_lock here, and that's enough to keep stateid's from going
away, but it's not enough to prevent the files they point to from going
away.  Take fi_lock and a reference and check for NULL, as we do in
other code.

Reported-by: default avatarNeilBrown <neilb@suse.de>
Fixes: 78599c42 ("nfsd4: add file to display list of client's opens")
Reviewed-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent becd2014

fs/nfsd/nfs4state.c

+19 −1
Original line number Diff line number Diff line
@@ -507,6 +507,17 @@ find_any_file(struct nfs4_file *f) 
	return ret;

}



static struct nfsd_file *find_deleg_file(struct nfs4_file *f)

{

	struct nfsd_file *ret = NULL;



	spin_lock(&f->fi_lock);

	if (f->fi_deleg_file)

		ret = nfsd_file_get(f->fi_deleg_file);

	spin_unlock(&f->fi_lock);

	return ret;

}



static atomic_long_t num_delegations;

unsigned long max_delegations;
@@ -2444,6 +2455,8 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st) 
	oo = ols->st_stateowner;

	nf = st->sc_file;

	file = find_any_file(nf);

	if (!file)

		return 0;



	seq_printf(s, "- ");

	nfs4_show_stateid(s, &st->sc_stateid);
@@ -2481,6 +2494,8 @@ static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st) 
	oo = ols->st_stateowner;

	nf = st->sc_file;

	file = find_any_file(nf);

	if (!file)

		return 0;



	seq_printf(s, "- ");

	nfs4_show_stateid(s, &st->sc_stateid);
@@ -2513,7 +2528,9 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st) 


	ds = delegstateid(st);

	nf = st->sc_file;

	file = nf->fi_deleg_file;

	file = find_deleg_file(nf);

	if (!file)

		return 0;



	seq_printf(s, "- ");

	nfs4_show_stateid(s, &st->sc_stateid);
@@ -2529,6 +2546,7 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st) 
	seq_printf(s, ", ");

	nfs4_show_fname(s, file);

	seq_printf(s, " }\n");

	nfsd_file_put(file);



	return 0;

}

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