f2fs: support xattr security labels

This patch adds the support of security labels for f2fs, which will be used
by Linus Security Models (LSMs).

Quote from http://en.wikipedia.org/wiki/Linux_Security_Modules:
"Linux Security Modules (LSM) is a framework that allows the Linux kernel to
support a variety of computer security models while avoiding favoritism toward
any single security implementation. The framework is licensed under the terms of
the GNU General Public License and is standard part of the Linux kernel since
Linux 2.6. AppArmor, SELinux, Smack and TOMOYO Linux are the currently accepted
modules in the official kernel.".

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 57 insertions, 7 deletions

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index ae61f359554..3ab07ecd86c 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -20,6 +20,7 @@
  */
 #include <linux/rwsem.h>
 #include <linux/f2fs_fs.h>
+#include <linux/security.h>
 #include "f2fs.h"
 #include "xattr.h"
 
@@ -43,6 +44,10 @@ static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
 		prefix = XATTR_TRUSTED_PREFIX;
 		prefix_len = XATTR_TRUSTED_PREFIX_LEN;
 		break;
+	case F2FS_XATTR_INDEX_SECURITY:
+		prefix = XATTR_SECURITY_PREFIX;
+		prefix_len = XATTR_SECURITY_PREFIX_LEN;
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -50,7 +55,7 @@ static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
 	total_len = prefix_len + name_len + 1;
 	if (list && total_len <= list_size) {
 		memcpy(list, prefix, prefix_len);
-		memcpy(list+prefix_len, name, name_len);
+		memcpy(list + prefix_len, name, name_len);
 		list[prefix_len + name_len] = '\0';
 	}
 	return total_len;
@@ -70,13 +75,14 @@ static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		break;
+	case F2FS_XATTR_INDEX_SECURITY:
+		break;
 	default:
 		return -EINVAL;
 	}
 	if (strcmp(name, "") == 0)
 		return -EINVAL;
-	return f2fs_getxattr(dentry->d_inode, type, name,
-			buffer, size);
+	return f2fs_getxattr(dentry->d_inode, type, name, buffer, size);
 }
 
 static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
@@ -93,13 +99,15 @@ static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 		break;
+	case F2FS_XATTR_INDEX_SECURITY:
+		break;
 	default:
 		return -EINVAL;
 	}
 	if (strcmp(name, "") == 0)
 		return -EINVAL;
 
-	return f2fs_setxattr(dentry->d_inode, type, name, value, size);
+	return f2fs_setxattr(dentry->d_inode, type, name, value, size, NULL);
 }
 
 static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
@@ -145,6 +153,31 @@ static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
 	return 0;
 }
 
+#ifdef CONFIG_F2FS_FS_SECURITY
+static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		void *page)
+{
+	const struct xattr *xattr;
+	int err = 0;
+
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
+				xattr->name, xattr->value,
+				xattr->value_len, (struct page *)page);
+		if (err < 0)
+			break;
+	}
+	return err;
+}
+
+int f2fs_init_security(struct inode *inode, struct inode *dir,
+				const struct qstr *qstr, struct page *ipage)
+{
+	return security_inode_init_security(inode, dir, qstr,
+				&f2fs_initxattrs, ipage);
+}
+#endif
+
 const struct xattr_handler f2fs_xattr_user_handler = {
 	.prefix	= XATTR_USER_PREFIX,
 	.flags	= F2FS_XATTR_INDEX_USER,
@@ -169,6 +202,14 @@ const struct xattr_handler f2fs_xattr_advise_handler = {
 	.set    = f2fs_xattr_advise_set,
 };
 
+const struct xattr_handler f2fs_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.flags	= F2FS_XATTR_INDEX_SECURITY,
+	.list	= f2fs_xattr_generic_list,
+	.get	= f2fs_xattr_generic_get,
+	.set	= f2fs_xattr_generic_set,
+};
+
 static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
 #ifdef CONFIG_F2FS_FS_POSIX_ACL
@@ -176,6 +217,9 @@ static const struct xattr_handler *f2fs_xattr_handler_map[] = {
 	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &f2fs_xattr_acl_default_handler,
 #endif
 	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
+#ifdef CONFIG_F2FS_FS_SECURITY
+	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
+#endif
 	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
 };
 
@@ -186,6 +230,9 @@ const struct xattr_handler *f2fs_xattr_handlers[] = {
 	&f2fs_xattr_acl_default_handler,
 #endif
 	&f2fs_xattr_trusted_handler,
+#ifdef CONFIG_F2FS_FS_SECURITY
+	&f2fs_xattr_security_handler,
+#endif
 	&f2fs_xattr_advise_handler,
 	NULL,
 };
@@ -300,7 +347,7 @@ cleanup:
 }
 
 int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
-					const void *value, size_t value_len)
+			const void *value, size_t value_len, struct page *ipage)
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 	struct f2fs_inode_info *fi = F2FS_I(inode);
@@ -339,7 +386,7 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
 		set_new_dnode(&dn, inode, NULL, NULL, fi->i_xattr_nid);
 		mark_inode_dirty(inode);
 
-		page = new_node_page(&dn, XATTR_NODE_OFFSET);
+		page = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
 		if (IS_ERR(page)) {
 			alloc_nid_failed(sbi, fi->i_xattr_nid);
 			fi->i_xattr_nid = 0;
@@ -439,7 +486,10 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
 		inode->i_ctime = CURRENT_TIME;
 		clear_inode_flag(fi, FI_ACL_MODE);
 	}
-	update_inode_page(inode);
+	if (ipage)
+		update_inode(inode, ipage);
+	else
+		update_inode_page(inode);
 	mutex_unlock_op(sbi, ilock);
 
 	return 0;