security, keys: convert key_user.usage from atomic_t to refcount_t

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 <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
This commit is contained in:
Elena Reshetova
2017-03-31 15:20:49 +03:00
committed by James Morris
parent fff292914d
commit ddb99e118e
4 changed files with 7 additions and 6 deletions

View File

@@ -340,7 +340,7 @@ static int proc_key_users_show(struct seq_file *m, void *v)
seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
from_kuid_munged(seq_user_ns(m), user->uid),
atomic_read(&user->usage),
refcount_read(&user->usage),
atomic_read(&user->nkeys),
atomic_read(&user->nikeys),
user->qnkeys,