Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...

[cascardo/linux.git] / kernel / cred.c

diff --git a/kernel/cred.c b/kernel/cred.c
index 48cea3d..8888afb 100644 (file)
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -29,17 +29,6 @@
 
 static struct kmem_cache *cred_jar;
 
-/*
- * The common credentials for the initial task's thread group
- */
-#ifdef CONFIG_KEYS
-static struct thread_group_cred init_tgcred = {
-       .usage  = ATOMIC_INIT(2),
-       .tgid   = 0,
-       .lock   = __SPIN_LOCK_UNLOCKED(init_cred.tgcred.lock),
-};
-#endif
-
 /*
  * The initial credentials for the initial task
  */
@@ -65,9 +54,6 @@ struct cred init_cred = {
        .user                   = INIT_USER,
        .user_ns                = &init_user_ns,
        .group_info             = &init_groups,
-#ifdef CONFIG_KEYS
-       .tgcred                 = &init_tgcred,
-#endif
 };
 
 static inline void set_cred_subscribers(struct cred *cred, int n)
@@ -95,36 +81,6 @@ static inline void alter_cred_subscribers(const struct cred *_cred, int n)
 #endif
 }
 
-/*
- * Dispose of the shared task group credentials
- */
-#ifdef CONFIG_KEYS
-static void release_tgcred_rcu(struct rcu_head *rcu)
-{
-       struct thread_group_cred *tgcred =
-               container_of(rcu, struct thread_group_cred, rcu);
-
-       BUG_ON(atomic_read(&tgcred->usage) != 0);
-
-       key_put(tgcred->session_keyring);
-       key_put(tgcred->process_keyring);
-       kfree(tgcred);
-}
-#endif
-
-/*
- * Release a set of thread group credentials.
- */
-static void release_tgcred(struct cred *cred)
-{
-#ifdef CONFIG_KEYS
-       struct thread_group_cred *tgcred = cred->tgcred;
-
-       if (atomic_dec_and_test(&tgcred->usage))
-               call_rcu(&tgcred->rcu, release_tgcred_rcu);
-#endif
-}
-
 /*
  * The RCU callback to actually dispose of a set of credentials
  */
@@ -150,9 +106,10 @@ static void put_cred_rcu(struct rcu_head *rcu)
 #endif
 
        security_cred_free(cred);
+       key_put(cred->session_keyring);
+       key_put(cred->process_keyring);
        key_put(cred->thread_keyring);
        key_put(cred->request_key_auth);
-       release_tgcred(cred);
        if (cred->group_info)
                put_group_info(cred->group_info);
        free_uid(cred->user);
@@ -246,15 +203,6 @@ struct cred *cred_alloc_blank(void)
        if (!new)
                return NULL;
 
-#ifdef CONFIG_KEYS
-       new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL);
-       if (!new->tgcred) {
-               kmem_cache_free(cred_jar, new);
-               return NULL;
-       }
-       atomic_set(&new->tgcred->usage, 1);
-#endif
-
        atomic_set(&new->usage, 1);
 #ifdef CONFIG_DEBUG_CREDENTIALS
        new->magic = CRED_MAGIC;
@@ -308,9 +256,10 @@ struct cred *prepare_creds(void)
        get_user_ns(new->user_ns);
 
 #ifdef CONFIG_KEYS
+       key_get(new->session_keyring);
+       key_get(new->process_keyring);
        key_get(new->thread_keyring);
        key_get(new->request_key_auth);
-       atomic_inc(&new->tgcred->usage);
 #endif
 
 #ifdef CONFIG_SECURITY
@@ -334,39 +283,20 @@ EXPORT_SYMBOL(prepare_creds);
  */
 struct cred *prepare_exec_creds(void)
 {
-       struct thread_group_cred *tgcred = NULL;
        struct cred *new;
 
-#ifdef CONFIG_KEYS
-       tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
-       if (!tgcred)
-               return NULL;
-#endif
-
        new = prepare_creds();
-       if (!new) {
-               kfree(tgcred);
+       if (!new)
                return new;
-       }
 
 #ifdef CONFIG_KEYS
        /* newly exec'd tasks don't get a thread keyring */
        key_put(new->thread_keyring);
        new->thread_keyring = NULL;
 
-       /* create a new per-thread-group creds for all this set of threads to
-        * share */
-       memcpy(tgcred, new->tgcred, sizeof(struct thread_group_cred));
-
-       atomic_set(&tgcred->usage, 1);
-       spin_lock_init(&tgcred->lock);
-
        /* inherit the session keyring; new process keyring */
-       key_get(tgcred->session_keyring);
-       tgcred->process_keyring = NULL;
-
-       release_tgcred(new);
-       new->tgcred = tgcred;
+       key_put(new->process_keyring);
+       new->process_keyring = NULL;
 #endif
 
        return new;
@@ -383,9 +313,6 @@ struct cred *prepare_exec_creds(void)
  */
 int copy_creds(struct task_struct *p, unsigned long clone_flags)
 {
-#ifdef CONFIG_KEYS
-       struct thread_group_cred *tgcred;
-#endif
        struct cred *new;
        int ret;
 
@@ -425,22 +352,12 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
                        install_thread_keyring_to_cred(new);
        }
 
-       /* we share the process and session keyrings between all the threads in
-        * a process - this is slightly icky as we violate COW credentials a
-        * bit */
+       /* The process keyring is only shared between the threads in a process;
+        * anything outside of those threads doesn't inherit.
+        */
        if (!(clone_flags & CLONE_THREAD)) {
-               tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
-               if (!tgcred) {
-                       ret = -ENOMEM;
-                       goto error_put;
-               }
-               atomic_set(&tgcred->usage, 1);
-               spin_lock_init(&tgcred->lock);
-               tgcred->process_keyring = NULL;
-               tgcred->session_keyring = key_get(new->tgcred->session_keyring);
-
-               release_tgcred(new);
-               new->tgcred = tgcred;
+               key_put(new->process_keyring);
+               new->process_keyring = NULL;
        }
 #endif
 
@@ -643,9 +560,6 @@ void __init cred_init(void)
  */
 struct cred *prepare_kernel_cred(struct task_struct *daemon)
 {
-#ifdef CONFIG_KEYS
-       struct thread_group_cred *tgcred;
-#endif
        const struct cred *old;
        struct cred *new;
 
@@ -653,14 +567,6 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon)
        if (!new)
                return NULL;
 
-#ifdef CONFIG_KEYS
-       tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
-       if (!tgcred) {
-               kmem_cache_free(cred_jar, new);
-               return NULL;
-       }
-#endif
-
        kdebug("prepare_kernel_cred() alloc %p", new);
 
        if (daemon)
@@ -678,13 +584,10 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon)
        get_group_info(new->group_info);
 
 #ifdef CONFIG_KEYS
-       atomic_set(&tgcred->usage, 1);
-       spin_lock_init(&tgcred->lock);
-       tgcred->process_keyring = NULL;
-       tgcred->session_keyring = NULL;
-       new->tgcred = tgcred;
-       new->request_key_auth = NULL;
+       new->session_keyring = NULL;
+       new->process_keyring = NULL;
        new->thread_keyring = NULL;
+       new->request_key_auth = NULL;
        new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
 #endif