CRED: Detach the credentials from task_struct

Detach the credentials from task_struct, duplicating them in copy_process()
and releasing them in __put_task_struct().

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

4 files changed, 33 insertions, 35 deletions

diff --git a/security/capability.c b/security/capability.c
index 245874819036..6c4b5137ca7b 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -340,12 +340,12 @@ static int cap_task_create(unsigned long clone_flags)
         return 0;
 }
 
-static int cap_task_alloc_security(struct task_struct *p)
+static int cap_cred_alloc_security(struct cred *cred)
 {
         return 0;
 }
 
-static void cap_task_free_security(struct task_struct *p)
+static void cap_cred_free(struct cred *cred)
 {
 }
 
@@ -890,8 +890,8 @@ void security_fixup_ops(struct security_operations *ops)
         set_to_cap_if_null(ops, file_receive);
         set_to_cap_if_null(ops, dentry_open);
         set_to_cap_if_null(ops, task_create);
-        set_to_cap_if_null(ops, task_alloc_security);
-        set_to_cap_if_null(ops, task_free_security);
+        set_to_cap_if_null(ops, cred_alloc_security);
+        set_to_cap_if_null(ops, cred_free);
         set_to_cap_if_null(ops, task_setuid);
         set_to_cap_if_null(ops, task_post_setuid);
         set_to_cap_if_null(ops, task_setgid);
diff --git a/security/security.c b/security/security.c
index 81c956a12300..d058f7d5b10a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -616,14 +616,14 @@ int security_task_create(unsigned long clone_flags)
         return security_ops->task_create(clone_flags);
 }
 
-int security_task_alloc(struct task_struct *p)
+int security_cred_alloc(struct cred *cred)
 {
-        return security_ops->task_alloc_security(p);
+        return security_ops->cred_alloc_security(cred);
 }
 
-void security_task_free(struct task_struct *p)
+void security_cred_free(struct cred *cred)
 {
-        security_ops->task_free_security(p);
+        security_ops->cred_free(cred);
 }
 
 int security_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 328308f2882a..658435dce37c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -158,7 +158,7 @@ static int selinux_secmark_enabled(void)
 
 /* Allocate and free functions for each kind of security blob. */
 
-static int task_alloc_security(struct task_struct *task)
+static int cred_alloc_security(struct cred *cred)
 {
         struct task_security_struct *tsec;
 
@@ -167,18 +167,11 @@ static int task_alloc_security(struct task_struct *task)
                 return -ENOMEM;
 
         tsec->osid = tsec->sid = SECINITSID_UNLABELED;
-        task->cred->security = tsec;
+        cred->security = tsec;
 
         return 0;
 }
 
-static void task_free_security(struct task_struct *task)
-{
-        struct task_security_struct *tsec = task->cred->security;
-        task->cred->security = NULL;
-        kfree(tsec);
-}
-
 static int inode_alloc_security(struct inode *inode)
 {
         struct task_security_struct *tsec = current->cred->security;
@@ -3184,17 +3177,17 @@ static int selinux_task_create(unsigned long clone_flags)
         return task_has_perm(current, current, PROCESS__FORK);
 }
 
-static int selinux_task_alloc_security(struct task_struct *tsk)
+static int selinux_cred_alloc_security(struct cred *cred)
 {
         struct task_security_struct *tsec1, *tsec2;
         int rc;
 
         tsec1 = current->cred->security;
 
-        rc = task_alloc_security(tsk);
+        rc = cred_alloc_security(cred);
         if (rc)
                 return rc;
-        tsec2 = tsk->cred->security;
+        tsec2 = cred->security;
 
         tsec2->osid = tsec1->osid;
         tsec2->sid = tsec1->sid;
@@ -3208,9 +3201,14 @@ static int selinux_task_alloc_security(struct task_struct *tsk)
         return 0;
 }
 
-static void selinux_task_free_security(struct task_struct *tsk)
+/*
+ * detach and free the LSM part of a set of credentials
+ */
+static void selinux_cred_free(struct cred *cred)
 {
-        task_free_security(tsk);
+        struct task_security_struct *tsec = cred->security;
+        cred->security = NULL;
+        kfree(tsec);
 }
 
 static int selinux_task_setuid(uid_t id0, uid_t id1, uid_t id2, int flags)
@@ -5552,8 +5550,8 @@ static struct security_operations selinux_ops = {
         .dentry_open =                  selinux_dentry_open,
 
         .task_create =                  selinux_task_create,
-        .task_alloc_security =          selinux_task_alloc_security,
-        .task_free_security =           selinux_task_free_security,
+        .cred_alloc_security =          selinux_cred_alloc_security,
+        .cred_free =                    selinux_cred_free,
         .task_setuid =                  selinux_task_setuid,
         .task_post_setuid =             selinux_task_post_setuid,
         .task_setgid =                  selinux_task_setgid,
@@ -5683,7 +5681,7 @@ static __init int selinux_init(void)
         printk(KERN_INFO "SELinux:  Initializing.\n");
 
         /* Set the security state for the initial task. */
-        if (task_alloc_security(current))
+        if (cred_alloc_security(current->cred))
                 panic("SELinux:  Failed to initialize initial task.\n");
         tsec = current->cred->security;
         tsec->osid = tsec->sid = SECINITSID_KERNEL;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 791da238d049..cc837314fb0e 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -975,8 +975,8 @@ static int smack_file_receive(struct file *file)
  */
 
 /**
- * smack_task_alloc_security - "allocate" a task blob
- * @tsk: the task in need of a blob
+ * smack_cred_alloc_security - "allocate" a task cred blob
+ * @cred: the task creds in need of a blob
  *
  * Smack isn't using copies of blobs. Everyone
  * points to an immutable list. No alloc required.
@@ -984,24 +984,24 @@ static int smack_file_receive(struct file *file)
  *
  * Always returns 0
  */
-static int smack_task_alloc_security(struct task_struct *tsk)
+static int smack_cred_alloc_security(struct cred *cred)
 {
-        tsk->cred->security = current->cred->security;
+        cred->security = current->cred->security;
 
         return 0;
 }
 
 /**
- * smack_task_free_security - "free" a task blob
- * @task: the task with the blob
+ * smack_cred_free - "free" task-level security credentials
+ * @cred: the credentials in question
  *
  * Smack isn't using copies of blobs. Everyone
  * points to an immutable list. The blobs never go away.
  * There is no leak here.
  */
-static void smack_task_free_security(struct task_struct *task)
+static void smack_cred_free(struct cred *cred)
 {
-        task->cred->security = NULL;
+        cred->security = NULL;
 }
 
 /**
@@ -2630,8 +2630,8 @@ struct security_operations smack_ops = {
         .file_send_sigiotask =          smack_file_send_sigiotask,
         .file_receive =                 smack_file_receive,
 
-        .task_alloc_security =          smack_task_alloc_security,
-        .task_free_security =           smack_task_free_security,
+        .cred_alloc_security =          smack_cred_alloc_security,
+        .cred_free =                    smack_cred_free,
         .task_post_setuid =             cap_task_post_setuid,
         .task_setpgid =                 smack_task_setpgid,
         .task_getpgid =                 smack_task_getpgid,