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-rw-r--r--kernel/cred.c46
1 files changed, 45 insertions, 1 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index cb6b5eda978..e6fcdd67b2e 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -68,7 +68,7 @@ static void release_tgcred_rcu(struct rcu_head *rcu)
/*
* Release a set of thread group credentials.
*/
-void release_tgcred(struct cred *cred)
+static void release_tgcred(struct cred *cred)
{
#ifdef CONFIG_KEYS
struct thread_group_cred *tgcred = cred->tgcred;
@@ -164,6 +164,50 @@ error:
EXPORT_SYMBOL(prepare_creds);
/*
+ * Prepare credentials for current to perform an execve()
+ * - The caller must hold current->cred_exec_mutex
+ */
+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);
+ 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;
+#endif
+
+ return new;
+}
+
+/*
* prepare new credentials for the usermode helper dispatcher
*/
struct cred *prepare_usermodehelper_creds(void)