CRED: Separate task security context from task_struct

Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

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>

1 files changed, 6 insertions, 5 deletions

diff --git a/security/keys/permission.c b/security/keys/permission.c
index 3b41f9b52537..baf3d5f31e71 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -22,6 +22,7 @@ int key_task_permission(const key_ref_t key_ref,
                         struct task_struct *context,
                         key_perm_t perm)
 {
+        struct cred *cred = context->cred;
         struct key *key;
         key_perm_t kperm;
         int ret;
@@ -29,7 +30,7 @@ int key_task_permission(const key_ref_t key_ref,
         key = key_ref_to_ptr(key_ref);
 
         /* use the second 8-bits of permissions for keys the caller owns */
-        if (key->uid == context->fsuid) {
+        if (key->uid == cred->fsuid) {
                 kperm = key->perm >> 16;
                 goto use_these_perms;
         }
@@ -37,14 +38,14 @@ int key_task_permission(const key_ref_t key_ref,
         /* use the third 8-bits of permissions for keys the caller has a group
          * membership in common with */
         if (key->gid != -1 && key->perm & KEY_GRP_ALL) {
-                if (key->gid == context->fsgid) {
+                if (key->gid == cred->fsgid) {
                         kperm = key->perm >> 8;
                         goto use_these_perms;
                 }
 
-                task_lock(context);
-                ret = groups_search(context->group_info, key->gid);
-                task_unlock(context);
+                spin_lock(&cred->lock);
+                ret = groups_search(cred->group_info, key->gid);
+                spin_unlock(&cred->lock);
 
                 if (ret) {
                         kperm = key->perm >> 8;