[PATCH] ext3: Enable atomic inode security labeling

This patch modifies ext3 to call the inode_init_security LSM hook to obtain
the security attribute for a newly created inode and to set the resulting
attribute on the new inode as part of the same transaction.  This parallels
the existing processing for setting ACLs on newly created inodes.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ext3/ialloc.c

@@ -607,6 +607,11 @@ got:
 		DQUOT_DROP(inode);
 		goto fail2;
   	}
+	err = ext3_init_security(handle,inode, dir);
+	if (err) {
+		DQUOT_FREE_INODE(inode);
+		goto fail2;
+	}
 	err = ext3_mark_inode_dirty(handle, inode);
 	if (err) {
 		ext3_std_error(sb, err);

fs/ext3/xattr.h

@@ -133,3 +133,14 @@ exit_ext3_xattr(void)
 #define ext3_xattr_handlers	NULL
 
 # endif  /* CONFIG_EXT3_FS_XATTR */
+
+#ifdef CONFIG_EXT3_FS_SECURITY
+extern int ext3_init_security(handle_t *handle, struct inode *inode,
+				struct inode *dir);
+#else
+static inline int ext3_init_security(handle_t *handle, struct inode *inode,
+				struct inode *dir)
+{
+	return 0;
+}
+#endif

fs/ext3/xattr_security.c

@@ -9,6 +9,7 @@
 #include <linux/smp_lock.h>
 #include <linux/ext3_jbd.h>
 #include <linux/ext3_fs.h>
+#include <linux/security.h>
 #include "xattr.h"
 
 static size_t
@@ -47,6 +48,27 @@ ext3_xattr_security_set(struct inode *inode, const char *name,
 			      value, size, flags);
 }
 
+int
+ext3_init_security(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	int err;
+	size_t len;
+	void *value;
+	char *name;
+
+	err = security_inode_init_security(inode, dir, &name, &value, &len);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return 0;
+		return err;
+	}
+	err = ext3_xattr_set_handle(handle, inode, EXT3_XATTR_INDEX_SECURITY,
+				    name, value, len, 0);
+	kfree(name);
+	kfree(value);
+	return err;
+}
+
 struct xattr_handler ext3_xattr_security_handler = {
 	.prefix	= XATTR_SECURITY_PREFIX,
 	.list	= ext3_xattr_security_list,