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, 9 insertions, 8 deletions

diff --git a/fs/open.c b/fs/open.c
index 500cc0c..b1238e1 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -425,6 +425,7 @@ out:
  */
 asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
 {
+	struct cred *cred = current->cred;
 	struct path path;
 	struct inode *inode;
 	int old_fsuid, old_fsgid;
@@ -434,18 +435,18 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
 	if (mode & ~S_IRWXO)	/* where's F_OK, X_OK, W_OK, R_OK? */
 		return -EINVAL;
 
-	old_fsuid = current->fsuid;
-	old_fsgid = current->fsgid;
+	old_fsuid = cred->fsuid;
+	old_fsgid = cred->fsgid;
 
-	current->fsuid = current->uid;
-	current->fsgid = current->gid;
+	cred->fsuid = cred->uid;
+	cred->fsgid = cred->gid;
 
 	if (!issecure(SECURE_NO_SETUID_FIXUP)) {
 		/* Clear the capabilities if we switch to a non-root user */
-		if (current->uid)
+		if (current->cred->uid)
 			old_cap = cap_set_effective(__cap_empty_set);
 		else
-			old_cap = cap_set_effective(current->cap_permitted);
+			old_cap = cap_set_effective(cred->cap_permitted);
 	}
 
 	res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
@@ -484,8 +485,8 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
 out_path_release:
 	path_put(&path);
 out:
-	current->fsuid = old_fsuid;
-	current->fsgid = old_fsgid;
+	cred->fsuid = old_fsuid;
+	cred->fsgid = old_fsgid;
 
 	if (!issecure(SECURE_NO_SETUID_FIXUP))
 		cap_set_effective(old_cap);