refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations.
Signed-off-by: Elena Reshetova <[email protected]> Signed-off-by: Hans Liljestrand <[email protected]> Signed-off-by: Kees Cook <[email protected]> Signed-off-by: David Windsor <[email protected]> --- fs/nfsd/nfs4state.c | 6 +++--- fs/nfsd/state.h | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 253fc93..a19f56c 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -359,7 +359,7 @@ put_nfs4_file(struct nfs4_file *fi) { might_lock(&state_lock); - if (atomic_dec_and_lock(&fi->fi_ref, &state_lock)) { + if (refcount_dec_and_lock(&fi->fi_ref, &state_lock)) { hlist_del_rcu(&fi->fi_hash); spin_unlock(&state_lock); WARN_ON_ONCE(!list_empty(&fi->fi_clnt_odstate)); @@ -3352,7 +3352,7 @@ static void nfsd4_init_file(struct knfsd_fh *fh, unsigned int hashval, { lockdep_assert_held(&state_lock); - atomic_set(&fp->fi_ref, 1); + refcount_set(&fp->fi_ref, 1); spin_lock_init(&fp->fi_lock); INIT_LIST_HEAD(&fp->fi_stateids); INIT_LIST_HEAD(&fp->fi_delegations); @@ -3648,7 +3648,7 @@ find_file_locked(struct knfsd_fh *fh, unsigned int hashval) hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash) { if (fh_match(&fp->fi_fhandle, fh)) { - if (atomic_inc_not_zero(&fp->fi_ref)) + if (refcount_inc_not_zero(&fp->fi_ref)) return fp; } } diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index 58eb5f4..4797429 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -482,7 +482,7 @@ struct nfs4_clnt_odstate { * the global state_lock spinlock. */ struct nfs4_file { - atomic_t fi_ref; + refcount_t fi_ref; spinlock_t fi_lock; struct hlist_node fi_hash; /* hash on fi_fhandle */ struct list_head fi_stateids; @@ -635,7 +635,7 @@ struct nfs4_file *find_file(struct knfsd_fh *fh); void put_nfs4_file(struct nfs4_file *fi); static inline void get_nfs4_file(struct nfs4_file *fi) { - atomic_inc(&fi->fi_ref); + refcount_inc(&fi->fi_ref); } struct file *find_any_file(struct nfs4_file *f); -- 2.7.4
