UBIFS: Add security.* XATTR support for the UBIFS

Artem: rename static functions so that they do not use the "ubifs_" prefix - we
       only use this prefix for non-static functions.
Artem: remove few junk white-space changes in file.c

Signed-off-by: Subodh Nijsure <snijsure@grid-net.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Ben Shelton <ben.shelton@ni.com>
Acked-by: Brad Mouring <brad.mouring@ni.com>
Acked-by: Terry Wilcox <terry.wilcox@ni.com>
Acked-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

4 files changed, 99 insertions, 0 deletions

diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index ea41649e4ca5..f7e8f765b36f 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -272,6 +272,10 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
                 goto out_budg;
         }
 
+        err = ubifs_init_security(dir, inode, &dentry->d_name);
+        if (err)
+                goto out_cancel;
+
         mutex_lock(&dir_ui->ui_mutex);
         dir->i_size += sz_change;
         dir_ui->ui_size = dir->i_size;
@@ -728,6 +732,10 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
                 goto out_budg;
         }
 
+        err = ubifs_init_security(dir, inode, &dentry->d_name);
+        if (err)
+                goto out_cancel;
+
         mutex_lock(&dir_ui->ui_mutex);
         insert_inode_hash(inode);
         inc_nlink(inode);
@@ -808,6 +816,10 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry,
         ui->data = dev;
         ui->data_len = devlen;
 
+        err = ubifs_init_security(dir, inode, &dentry->d_name);
+        if (err)
+                goto out_cancel;
+
         mutex_lock(&dir_ui->ui_mutex);
         dir->i_size += sz_change;
         dir_ui->ui_size = dir->i_size;
@@ -884,6 +896,10 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
         ui->data_len = len;
         inode->i_size = ubifs_inode(inode)->ui_size = len;
 
+        err = ubifs_init_security(dir, inode, &dentry->d_name);
+        if (err)
+                goto out_cancel;
+
         mutex_lock(&dir_ui->ui_mutex);
         dir->i_size += sz_change;
         dir_ui->ui_size = dir->i_size;
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 106bf20629ce..e6420677cebc 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2039,6 +2039,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
         if (c->max_inode_sz > MAX_LFS_FILESIZE)
                 sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
         sb->s_op = &ubifs_super_operations;
+        sb->s_xattr = ubifs_xattr_handlers;
 
         mutex_lock(&c->umount_mutex);
         err = mount_ubifs(c);
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index c4fe900c67ab..bc04b9c69891 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -36,6 +36,7 @@
 #include <linux/mtd/ubi.h>
 #include <linux/pagemap.h>
 #include <linux/backing-dev.h>
+#include <linux/security.h>
 #include "ubifs-media.h"
 
 /* Version of this UBIFS implementation */
@@ -1465,6 +1466,7 @@ extern spinlock_t ubifs_infos_lock;
 extern atomic_long_t ubifs_clean_zn_cnt;
 extern struct kmem_cache *ubifs_inode_slab;
 extern const struct super_operations ubifs_super_operations;
+extern const struct xattr_handler *ubifs_xattr_handlers[];
 extern const struct address_space_operations ubifs_file_address_operations;
 extern const struct file_operations ubifs_file_operations;
 extern const struct inode_operations ubifs_file_inode_operations;
@@ -1754,6 +1756,8 @@ ssize_t ubifs_getxattr(struct dentry *dentry, const char *name, void *buf,
                        size_t size);
 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 int ubifs_removexattr(struct dentry *dentry, const char *name);
+int ubifs_init_security(struct inode *dentry, struct inode *inode,
+                        const struct qstr *qstr);
 
 /* super.c */
 struct inode *ubifs_iget(struct super_block *sb, unsigned long inum);
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index c3254a681a78..2bdab8b11f3f 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -575,3 +575,81 @@ out_free:
         kfree(xent);
         return err;
 }
+
+static size_t security_listxattr(struct dentry *d, char *list, size_t list_size,
+                                 const char *name, size_t name_len, int flags)
+{
+        const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
+        const size_t total_len = prefix_len + name_len + 1;
+
+        if (list && total_len <= list_size) {
+                memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+                memcpy(list + prefix_len, name, name_len);
+                list[prefix_len + name_len] = '\0';
+        }
+
+        return total_len;
+}
+
+static int security_getxattr(struct dentry *d, const char *name, void *buffer,
+                      size_t size, int flags)
+{
+        return ubifs_getxattr(d, name, buffer, size);
+}
+
+static int security_setxattr(struct dentry *d, const char *name,
+                             const void *value, size_t size, int flags,
+                             int handler_flags)
+{
+        return ubifs_setxattr(d, name, value, size, flags);
+}
+
+static const struct xattr_handler ubifs_xattr_security_handler = {
+        .prefix = XATTR_SECURITY_PREFIX,
+        .list   = security_listxattr,
+        .get    = security_getxattr,
+        .set    = security_setxattr,
+};
+
+const struct xattr_handler *ubifs_xattr_handlers[] = {
+        &ubifs_xattr_security_handler,
+        NULL,
+};
+
+static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
+                      void *fs_info)
+{
+        const struct xattr *xattr;
+        char *name;
+        int err = 0;
+
+        for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+                name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
+                               strlen(xattr->name) + 1, GFP_NOFS);
+                if (!name) {
+                        err = -ENOMEM;
+                        break;
+                }
+                strcpy(name, XATTR_SECURITY_PREFIX);
+                strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
+                err = setxattr(inode, name, xattr->value, xattr->value_len, 0);
+                kfree(name);
+                if (err < 0)
+                        break;
+        }
+
+        return err;
+}
+
+int ubifs_init_security(struct inode *dentry, struct inode *inode,
+                        const struct qstr *qstr)
+{
+        int err;
+
+        mutex_lock(&inode->i_mutex);
+        err = security_inode_init_security(inode, dentry, qstr,
+                                           &init_xattrs, 0);
+        mutex_unlock(&inode->i_mutex);
+
+        return err;
+}