5 files changed, 19 insertions, 24 deletions

diff --git a/security/keys/compat.c b/security/keys/compat.c
index c92d42b..1c26176 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -24,7 +24,7 @@
  *
  * If successful, 0 will be returned.
  */
-long compat_keyctl_instantiate_key_iov(
+static long compat_keyctl_instantiate_key_iov(
 	key_serial_t id,
 	const struct compat_iovec __user *_payload_iov,
 	unsigned ioc,
@@ -33,7 +33,7 @@ long compat_keyctl_instantiate_key_iov(
 	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
 	long ret;
 
-	if (_payload_iov == 0 || ioc == 0)
+	if (!_payload_iov || !ioc)
 		goto no_payload;
 
 	ret = compat_rw_copy_check_uvector(WRITE, _payload_iov, ioc,
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 3dcbf86..22ff052 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -149,7 +149,7 @@ extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
 #define KEY_LOOKUP_FOR_UNLINK	0x04
 
 extern long join_session_keyring(const char *name);
-extern void key_change_session_keyring(struct task_work *twork);
+extern void key_change_session_keyring(struct callback_head *twork);
 
 extern struct work_struct key_gc_work;
 extern unsigned key_gc_delay;
@@ -242,7 +242,7 @@ extern long keyctl_instantiate_key_iov(key_serial_t,
 extern long keyctl_invalidate_key(key_serial_t);
 
 extern long keyctl_instantiate_key_common(key_serial_t,
-					  const struct iovec __user *,
+					  const struct iovec *,
 					  unsigned, size_t, key_serial_t);
 
 /*
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 0f5b3f0..3364fbf 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1106,7 +1106,7 @@ long keyctl_instantiate_key_iov(key_serial_t id,
 	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
 	long ret;
 
-	if (_payload_iov == 0 || ioc == 0)
+	if (!_payload_iov || !ioc)
 		goto no_payload;
 
 	ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
@@ -1456,7 +1456,7 @@ long keyctl_session_to_parent(void)
 {
 	struct task_struct *me, *parent;
 	const struct cred *mycred, *pcred;
-	struct task_work *newwork, *oldwork;
+	struct callback_head *newwork, *oldwork;
 	key_ref_t keyring_r;
 	struct cred *cred;
 	int ret;
@@ -1466,19 +1466,17 @@ long keyctl_session_to_parent(void)
 		return PTR_ERR(keyring_r);
 
 	ret = -ENOMEM;
-	newwork = kmalloc(sizeof(struct task_work), GFP_KERNEL);
-	if (!newwork)
-		goto error_keyring;
 
 	/* our parent is going to need a new cred struct, a new tgcred struct
 	 * and new security data, so we allocate them here to prevent ENOMEM in
 	 * our parent */
 	cred = cred_alloc_blank();
 	if (!cred)
-		goto error_newwork;
+		goto error_keyring;
+	newwork = &cred->rcu;
 
 	cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
-	init_task_work(newwork, key_change_session_keyring, cred);
+	init_task_work(newwork, key_change_session_keyring);
 
 	me = current;
 	rcu_read_lock();
@@ -1488,6 +1486,7 @@ long keyctl_session_to_parent(void)
 	oldwork = NULL;
 	parent = me->real_parent;
 
+	task_lock(parent);
 	/* the parent mustn't be init and mustn't be a kernel thread */
 	if (parent->pid <= 1 || !parent->mm)
 		goto unlock;
@@ -1531,20 +1530,15 @@ long keyctl_session_to_parent(void)
 	if (!ret)
 		newwork = NULL;
 unlock:
+	task_unlock(parent);
 	write_unlock_irq(&tasklist_lock);
 	rcu_read_unlock();
-	if (oldwork) {
-		put_cred(oldwork->data);
-		kfree(oldwork);
-	}
-	if (newwork) {
-		put_cred(newwork->data);
-		kfree(newwork);
-	}
+	if (oldwork)
+		put_cred(container_of(oldwork, struct cred, rcu));
+	if (newwork)
+		put_cred(cred);
 	return ret;
 
-error_newwork:
-	kfree(newwork);
 error_keyring:
 	key_ref_put(keyring_r);
 	return ret;
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 7445875..81e7852 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -751,6 +751,7 @@ static void keyring_unlink_rcu_disposal(struct rcu_head *rcu)
 int __key_link_begin(struct key *keyring, const struct key_type *type,
 		     const char *description, unsigned long *_prealloc)
 	__acquires(&keyring->sem)
+	__acquires(&keyring_serialise_link_sem)
 {
 	struct keyring_list *klist, *nklist;
 	unsigned long prealloc;
@@ -960,6 +961,7 @@ void __key_link(struct key *keyring, struct key *key,
 void __key_link_end(struct key *keyring, struct key_type *type,
 		    unsigned long prealloc)
 	__releases(&keyring->sem)
+	__releases(&keyring_serialise_link_sem)
 {
 	BUG_ON(type == NULL);
 	BUG_ON(type->name == NULL);
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 4ad54ee..54339cf 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -834,12 +834,11 @@ error:
  * Replace a process's session keyring on behalf of one of its children when
  * the target  process is about to resume userspace execution.
  */
-void key_change_session_keyring(struct task_work *twork)
+void key_change_session_keyring(struct callback_head *twork)
 {
 	const struct cred *old = current_cred();
-	struct cred *new = twork->data;
+	struct cred *new = container_of(twork, struct cred, rcu);
 
-	kfree(twork);
 	if (unlikely(current->flags & PF_EXITING)) {
 		put_cred(new);
 		return;