1 files changed, 25 insertions, 65 deletions

diff --git a/kernel/cred.c b/kernel/cred.c
index 62af1816c235..60bc8b1e32e6 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -17,7 +17,6 @@
 #include <linux/init_task.h>
 #include <linux/security.h>
 #include <linux/cn_proc.h>
-#include "cred-internals.h"
 
 #if 0
 #define kdebug(FMT, ...) \
@@ -210,6 +209,31 @@ void exit_creds(struct task_struct *tsk)
         }
 }
 
+/**
+ * get_task_cred - Get another task's objective credentials
+ * @task: The task to query
+ *
+ * Get the objective credentials of a task, pinning them so that they can't go
+ * away.  Accessing a task's credentials directly is not permitted.
+ *
+ * The caller must also make sure task doesn't get deleted, either by holding a
+ * ref on task or by holding tasklist_lock to prevent it from being unlinked.
+ */
+const struct cred *get_task_cred(struct task_struct *task)
+{
+        const struct cred *cred;
+
+        rcu_read_lock();
+
+        do {
+                cred = __task_cred((task));
+                BUG_ON(!cred);
+        } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage));
+
+        rcu_read_unlock();
+        return cred;
+}
+
 /*
  * Allocate blank credentials, such that the credentials can be filled in at a
  * later date without risk of ENOMEM.
@@ -348,66 +372,6 @@ struct cred *prepare_exec_creds(void)
 }
 
 /*
- * prepare new credentials for the usermode helper dispatcher
- */
-struct cred *prepare_usermodehelper_creds(void)
-{
-#ifdef CONFIG_KEYS
-        struct thread_group_cred *tgcred = NULL;
-#endif
-        struct cred *new;
-
-#ifdef CONFIG_KEYS
-        tgcred = kzalloc(sizeof(*new->tgcred), GFP_ATOMIC);
-        if (!tgcred)
-                return NULL;
-#endif
-
-        new = kmem_cache_alloc(cred_jar, GFP_ATOMIC);
-        if (!new)
-                goto free_tgcred;
-
-        kdebug("prepare_usermodehelper_creds() alloc %p", new);
-
-        memcpy(new, &init_cred, sizeof(struct cred));
-
-        atomic_set(&new->usage, 1);
-        set_cred_subscribers(new, 0);
-        get_group_info(new->group_info);
-        get_uid(new->user);
-
-#ifdef CONFIG_KEYS
-        new->thread_keyring = NULL;
-        new->request_key_auth = NULL;
-        new->jit_keyring = KEY_REQKEY_DEFL_DEFAULT;
-
-        atomic_set(&tgcred->usage, 1);
-        spin_lock_init(&tgcred->lock);
-        new->tgcred = tgcred;
-#endif
-
-#ifdef CONFIG_SECURITY
-        new->security = NULL;
-#endif
-        if (security_prepare_creds(new, &init_cred, GFP_ATOMIC) < 0)
-                goto error;
-        validate_creds(new);
-
-        BUG_ON(atomic_read(&new->usage) != 1);
-        return new;
-
-error:
-        put_cred(new);
-        return NULL;
-
-free_tgcred:
-#ifdef CONFIG_KEYS
-        kfree(tgcred);
-#endif
-        return NULL;
-}
-
-/*
  * Copy credentials for the new process created by fork()
  *
  * We share if we can, but under some circumstances we have to generate a new
@@ -523,8 +487,6 @@ int commit_creds(struct cred *new)
 #endif
         BUG_ON(atomic_read(&new->usage) < 1);
 
-        security_commit_creds(new, old);
-
         get_cred(new); /* we will require a ref for the subj creds too */
 
         /* dumpability changes */
@@ -560,8 +522,6 @@ int commit_creds(struct cred *new)
                 atomic_dec(&old->user->processes);
         alter_cred_subscribers(old, -2);
 
-        sched_switch_user(task);
-
         /* send notifications */
         if (new->uid   != old->uid  ||
             new->euid  != old->euid ||