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>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/cred.h b/include/linux/cred.h
index 166ce4ddba64..62b9e532422d 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -72,6 +72,21 @@ extern int in_group_p(gid_t);
 extern int in_egroup_p(gid_t);
 
 /*
+ * The common credentials for a thread group
+ * - shared by CLONE_THREAD
+ */
+#ifdef CONFIG_KEYS
+struct thread_group_cred {
+        atomic_t        usage;
+        pid_t           tgid;                   /* thread group process ID */
+        spinlock_t      lock;
+        struct key      *session_keyring;       /* keyring inherited over fork */
+        struct key      *process_keyring;       /* keyring private to this process */
+        struct rcu_head rcu;                    /* RCU deletion hook */
+};
+#endif
+
+/*
  * The security context of a task
  *
  * The parts of the context break down into two categories:
@@ -114,6 +129,7 @@ struct cred {
                                          * keys to */
         struct key      *thread_keyring; /* keyring private to this thread */
         struct key      *request_key_auth; /* assumed request_key authority */
+        struct thread_group_cred *tgcred; /* thread-group shared credentials */
 #endif
 #ifdef CONFIG_SECURITY
         void            *security;      /* subjective LSM security */