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authorElena Reshetova <elena.reshetova@intel.com>2017-03-31 15:20:48 +0300
committerJames Morris <james.l.morris@oracle.com>2017-04-03 10:49:05 +1000
commitfff292914d3a2f1efd05ca71c2ba72a3c663201e (patch)
tree627f9870ad82da8f6f06cca86a73e3b7e2fc97d5 /security
parent8291798dcf059cdc5e55a59b2c4ad70ae14508c2 (diff)
downloadlinux-fff292914d3a2f1efd05ca71c2ba72a3c663201e.tar.bz2
security, keys: convert key.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>
Diffstat (limited to 'security')
-rw-r--r--security/keys/gc.c2
-rw-r--r--security/keys/key.c6
-rw-r--r--security/keys/keyring.c8
-rw-r--r--security/keys/proc.c2
-rw-r--r--security/keys/request_key_auth.c2
5 files changed, 10 insertions, 10 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c
index addf060399e0..44789256c88c 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -220,7 +220,7 @@ continue_scanning:
key = rb_entry(cursor, struct key, serial_node);
cursor = rb_next(cursor);
- if (atomic_read(&key->usage) == 0)
+ if (refcount_read(&key->usage) == 0)
goto found_unreferenced_key;
if (unlikely(gc_state & KEY_GC_REAPING_DEAD_1)) {
diff --git a/security/keys/key.c b/security/keys/key.c
index 346fbf201c22..ff9244392d35 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -285,7 +285,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
if (!key->index_key.description)
goto no_memory_3;
- atomic_set(&key->usage, 1);
+ refcount_set(&key->usage, 1);
init_rwsem(&key->sem);
lockdep_set_class(&key->sem, &type->lock_class);
key->index_key.type = type;
@@ -621,7 +621,7 @@ void key_put(struct key *key)
if (key) {
key_check(key);
- if (atomic_dec_and_test(&key->usage))
+ if (refcount_dec_and_test(&key->usage))
schedule_work(&key_gc_work);
}
}
@@ -656,7 +656,7 @@ not_found:
found:
/* pretend it doesn't exist if it is awaiting deletion */
- if (atomic_read(&key->usage) == 0)
+ if (refcount_read(&key->usage) == 0)
goto not_found;
/* this races with key_put(), but that doesn't matter since key_put()
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index c91e4e0cea08..3d95f7d02ba1 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -1033,7 +1033,7 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
/* we've got a match but we might end up racing with
* key_cleanup() if the keyring is currently 'dead'
* (ie. it has a zero usage count) */
- if (!atomic_inc_not_zero(&keyring->usage))
+ if (!refcount_inc_not_zero(&keyring->usage))
continue;
keyring->last_used_at = current_kernel_time().tv_sec;
goto out;
@@ -1250,14 +1250,14 @@ int key_link(struct key *keyring, struct key *key)
struct assoc_array_edit *edit;
int ret;
- kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage));
+ kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage));
key_check(keyring);
key_check(key);
ret = __key_link_begin(keyring, &key->index_key, &edit);
if (ret == 0) {
- kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage));
+ kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage));
ret = __key_link_check_restriction(keyring, key);
if (ret == 0)
ret = __key_link_check_live_key(keyring, key);
@@ -1266,7 +1266,7 @@ int key_link(struct key *keyring, struct key *key)
__key_link_end(keyring, &key->index_key, edit);
}
- kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage));
+ kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage));
return ret;
}
EXPORT_SYMBOL(key_link);
diff --git a/security/keys/proc.c b/security/keys/proc.c
index b9f531c9e4fa..69199f18bfb3 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -252,7 +252,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
showflag(key, 'N', KEY_FLAG_NEGATIVE),
showflag(key, 'i', KEY_FLAG_INVALIDATED),
- atomic_read(&key->usage),
+ refcount_read(&key->usage),
xbuf,
key->perm,
from_kuid_munged(seq_user_ns(m), key->uid),
diff --git a/security/keys/request_key_auth.c b/security/keys/request_key_auth.c
index 6bbe2f535f08..0f062156dfb2 100644
--- a/security/keys/request_key_auth.c
+++ b/security/keys/request_key_auth.c
@@ -213,7 +213,7 @@ struct key *request_key_auth_new(struct key *target, const void *callout_info,
if (ret < 0)
goto error_inst;
- kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
+ kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
return authkey;
auth_key_revoked: