CRED: Separate per-task-group keyrings from signal_struct
Separate per-task-group keyrings from signal_struct and dangle their anchor
from the cred struct rather than the signal_struct.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 212601e..70ee934 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -189,7 +189,7 @@
might_sleep();
- if (!tsk->signal->process_keyring) {
+ if (!tsk->cred->tgcred->process_keyring) {
sprintf(buf, "_pid.%u", tsk->tgid);
keyring = keyring_alloc(buf, tsk->cred->uid, tsk->cred->gid, tsk,
@@ -200,12 +200,12 @@
}
/* attach keyring */
- spin_lock_irq(&tsk->sighand->siglock);
- if (!tsk->signal->process_keyring) {
- tsk->signal->process_keyring = keyring;
+ spin_lock_irq(&tsk->cred->tgcred->lock);
+ if (!tsk->cred->tgcred->process_keyring) {
+ tsk->cred->tgcred->process_keyring = keyring;
keyring = NULL;
}
- spin_unlock_irq(&tsk->sighand->siglock);
+ spin_unlock_irq(&tsk->cred->tgcred->lock);
key_put(keyring);
}
@@ -235,11 +235,11 @@
sprintf(buf, "_ses.%u", tsk->tgid);
flags = KEY_ALLOC_QUOTA_OVERRUN;
- if (tsk->signal->session_keyring)
+ if (tsk->cred->tgcred->session_keyring)
flags = KEY_ALLOC_IN_QUOTA;
- keyring = keyring_alloc(buf, tsk->cred->uid, tsk->cred->gid, tsk,
- flags, NULL);
+ keyring = keyring_alloc(buf, tsk->cred->uid, tsk->cred->gid,
+ tsk, flags, NULL);
if (IS_ERR(keyring))
return PTR_ERR(keyring);
}
@@ -248,10 +248,10 @@
}
/* install the keyring */
- spin_lock_irq(&tsk->sighand->siglock);
- old = tsk->signal->session_keyring;
- rcu_assign_pointer(tsk->signal->session_keyring, keyring);
- spin_unlock_irq(&tsk->sighand->siglock);
+ spin_lock_irq(&tsk->cred->tgcred->lock);
+ old = tsk->cred->tgcred->session_keyring;
+ rcu_assign_pointer(tsk->cred->tgcred->session_keyring, keyring);
+ spin_unlock_irq(&tsk->cred->tgcred->lock);
/* we're using RCU on the pointer, but there's no point synchronising
* on it if it didn't previously point to anything */
@@ -266,28 +266,6 @@
/*****************************************************************************/
/*
- * copy the keys in a thread group for fork without CLONE_THREAD
- */
-int copy_thread_group_keys(struct task_struct *tsk)
-{
- key_check(current->thread_group->session_keyring);
- key_check(current->thread_group->process_keyring);
-
- /* no process keyring yet */
- tsk->signal->process_keyring = NULL;
-
- /* same session keyring */
- rcu_read_lock();
- tsk->signal->session_keyring =
- key_get(rcu_dereference(current->signal->session_keyring));
- rcu_read_unlock();
-
- return 0;
-
-} /* end copy_thread_group_keys() */
-
-/*****************************************************************************/
-/*
* copy the keys for fork
*/
int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
@@ -307,17 +285,6 @@
/*****************************************************************************/
/*
- * dispose of thread group keys upon thread group destruction
- */
-void exit_thread_group_keys(struct signal_struct *tg)
-{
- key_put(tg->session_keyring);
- key_put(tg->process_keyring);
-
-} /* end exit_thread_group_keys() */
-
-/*****************************************************************************/
-/*
* dispose of per-thread keys upon thread exit
*/
void exit_keys(struct task_struct *tsk)
@@ -344,10 +311,10 @@
key_put(old);
/* discard the process keyring from a newly exec'd task */
- spin_lock_irq(&tsk->sighand->siglock);
- old = tsk->signal->process_keyring;
- tsk->signal->process_keyring = NULL;
- spin_unlock_irq(&tsk->sighand->siglock);
+ spin_lock_irq(&tsk->cred->tgcred->lock);
+ old = tsk->cred->tgcred->process_keyring;
+ tsk->cred->tgcred->process_keyring = NULL;
+ spin_unlock_irq(&tsk->cred->tgcred->lock);
key_put(old);
@@ -452,9 +419,9 @@
}
/* search the process keyring second */
- if (context->signal->process_keyring) {
+ if (cred->tgcred->process_keyring) {
key_ref = keyring_search_aux(
- make_key_ref(context->signal->process_keyring, 1),
+ make_key_ref(cred->tgcred->process_keyring, 1),
context, type, description, match);
if (!IS_ERR(key_ref))
goto found;
@@ -473,11 +440,11 @@
}
/* search the session keyring */
- if (context->signal->session_keyring) {
+ if (cred->tgcred->session_keyring) {
rcu_read_lock();
key_ref = keyring_search_aux(
make_key_ref(rcu_dereference(
- context->signal->session_keyring),
+ cred->tgcred->session_keyring),
1),
context, type, description, match);
rcu_read_unlock();
@@ -586,11 +553,13 @@
{
struct request_key_auth *rka;
struct task_struct *t = current;
- struct cred *cred = current_cred();
+ struct cred *cred;
struct key *key;
key_ref_t key_ref, skey_ref;
int ret;
+try_again:
+ cred = get_current_cred();
key_ref = ERR_PTR(-ENOKEY);
switch (id) {
@@ -604,6 +573,7 @@
key = ERR_PTR(ret);
goto error;
}
+ goto reget_creds;
}
key = cred->thread_keyring;
@@ -612,7 +582,7 @@
break;
case KEY_SPEC_PROCESS_KEYRING:
- if (!t->signal->process_keyring) {
+ if (!cred->tgcred->process_keyring) {
if (!create)
goto error;
@@ -621,15 +591,16 @@
key = ERR_PTR(ret);
goto error;
}
+ goto reget_creds;
}
- key = t->signal->process_keyring;
+ key = cred->tgcred->process_keyring;
atomic_inc(&key->usage);
key_ref = make_key_ref(key, 1);
break;
case KEY_SPEC_SESSION_KEYRING:
- if (!t->signal->session_keyring) {
+ if (!cred->tgcred->session_keyring) {
/* always install a session keyring upon access if one
* doesn't exist yet */
ret = install_user_keyrings();
@@ -639,10 +610,11 @@
cred->user->session_keyring);
if (ret < 0)
goto error;
+ goto reget_creds;
}
rcu_read_lock();
- key = rcu_dereference(t->signal->session_keyring);
+ key = rcu_dereference(cred->tgcred->session_keyring);
atomic_inc(&key->usage);
rcu_read_unlock();
key_ref = make_key_ref(key, 1);
@@ -758,6 +730,7 @@
goto invalid_key;
error:
+ put_cred(cred);
return key_ref;
invalid_key:
@@ -765,6 +738,12 @@
key_ref = ERR_PTR(ret);
goto error;
+ /* if we attempted to install a keyring, then it may have caused new
+ * creds to be installed */
+reget_creds:
+ put_cred(cred);
+ goto try_again;
+
} /* end lookup_user_key() */
/*****************************************************************************/
@@ -777,6 +756,7 @@
long join_session_keyring(const char *name)
{
struct task_struct *tsk = current;
+ struct cred *cred = current->cred;
struct key *keyring;
long ret;
@@ -787,7 +767,7 @@
goto error;
rcu_read_lock();
- ret = rcu_dereference(tsk->signal->session_keyring)->serial;
+ ret = rcu_dereference(cred->tgcred->session_keyring)->serial;
rcu_read_unlock();
goto error;
}
@@ -799,7 +779,7 @@
keyring = find_keyring_by_name(name, false);
if (PTR_ERR(keyring) == -ENOKEY) {
/* not found - try and create a new one */
- keyring = keyring_alloc(name, tsk->cred->uid, tsk->cred->gid, tsk,
+ keyring = keyring_alloc(name, cred->uid, cred->gid, tsk,
KEY_ALLOC_IN_QUOTA, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);